
^{6}Li (2002TI10)(See Energy Level Diagrams for ^{6}Li) GENERAL: References to articles on general properties of ^{6}He published since the previous review (1988AJ01) are grouped into categories and isted, along with brief descriptions of each item, in the General Tables for ^{6}Li located on our website at (nucldata.tunl.duke.edu/NuclData/General_Tables/6li.shtml). See also 3 [Electromagnetic Transitions in A = 57] (in PDF or PS) and 6.4 [Table of Energy Levels] (in PDF or PS). Ground State Properties:
Q = 0.818(17) mb (1998CE04). The interaction nuclear radius of ^{6}Li is 2.09 ± 0.02 fm (1985TA18). These authors have also derived nuclear matter, charge and neutron r.m.s. radii. Quadrupole moment: The tiny quadrupole moment of ^{6}Li poses a difficult task for theoretical calculations. Except for a phenomenological (1985ME02), a microscopic cluster (1986ME13), and a GreensFunction MonteCarlo (1997PU03) calculation, the models fail even to predict the sign. See the discussion of threebody models in (1993SC30). In (1991UN02), this failure of the threebody models is blamed on the missing antisymmetrization of the valence nucleons with the nucleons in the alphacore. Another microscopic cluster calculation (1992CS04) considers the findings of (1986ME13) to be due to a fortuitous choice of the model space. Asymptotic D/S ratio^{1}: The ratio of the D and Sstate asymptotic normalization constants, referred to in the literature as η, has been used widely to quantify the properties of the Dstate wave function. There is general agreement in the A = 2  4 systems between theoretical calculations and empirical determinations of the normalization constants. See (1988WE20, 1990EI01, 1990LE24). The Sstate α + d normalization constant for ^{6}Li appears to be well determined (1993BL09, 1999GE02), but both the magnitude and sign of η are uncertain.
^{1} We are very grateful to K.D. Veal and C.R. Brune for providing these comments on the asymptotic D/S ratio for ^{6}Li. In a twobody α + d model it was found (1984NI01) that in order to reproduce the experimental quadrupole moment Q, the wave functions must have η < 0. However, threebody (α + n + p) models consistently result in predictions of η > 0 (1990LE24, 1995KU08). Recent microscopic sixbody calculations using realistic NN potentials predict η = 0.07 (1996FO04). The asymptotic D/S ratio has been probed empirically by studying scattering processes, transfer reactions, and ^{6}Li breakup. These determinations usually rely on an underlying assumption as to the scattering or reaction mechanism. The S and Dstate asymptotic normalization constants were determined in a study of dα scattering (1978BO43) from which η was found to be +0.005 ± 0.014. Several pol. ^{6}Li + ^{58}Ni elastic scattering studies (1984NI01, 1995DE06, 1995RU14) have described polarization observables with η ≈ 0.01, while an investigation of the breakup of pol. ^{6}Li on ^{1}H suggests η > 0 (1992PU03). A study of the ^{6}Li(d, α)^{4}He reaction (1990SA47) found that η should lie in the range 0.010 to 0.015. Recently, a phaseshift analysis of pol. ^{6}Li + ^{4}He scattering determined η = 0.025 ± 0.006 ± 0.010 (1999GE02) while an analysis of (pol. ^{6}Li, d) transfer reactions resulted in a near zero value of η = +0.0003 ± 0.0009 (1998VE03). Based on these theoretical and empirical results, we conclude that both the magnitude and sign of η for the ^{6}Li → α + d wave function are not well determined. See also (1998VE03, 1999GE02). Isotopic abundance: (7.5 ± 0.2)% (1984DE53). See also (1987LA1J, 1988LA1C). For estimates of the parityviolating αdecay width of ^{6}Li*(3.56) [0^{+}; T = 1] see (1983RO12, 1984BU01, 1986BU07).
Differential cross sections were measured at E = 0.7 GeV/A by (2000DOZY, 2001EG02). Matter distribution radii and halo features of ^{6}Li*(3.56) were deduced.
Measurements of cross sections at E_{α} = 418, 420 MeV are reported by (2000AN15, 2000AN31). Halo features of ^{6}Li* were deduced.
In the previous review (1988AJ01), information on radiative capture of ^{3}H on ^{3}He was summarized as follows: "Capture γrays (reaction (a)) to the first three states of ^{6}Li [γ_{0}, γ_{1}, γ_{2}] have been observed for E(^{3}He) = 0.5 to 25.8 MeV, while the yields of γ_{3} and γ_{4} have been measured for E(^{3}He) = 12.6 to 25.8 MeV. The γ_{2} excitation function does not show resonance structure. However, the γ_{0}, γ_{1}, γ_{3} and γ_{4} yields do show broad maxima at E(^{3}He) = 5.0 ± 0.4 [γ_{0}, γ_{1}], 20.6 ± 0.4 [γ_{1}], ≈ 21 [γ_{3}] and 21.8 ± 0.8 [γ_{4}] MeV. The magnitude of the groundstatecapture cross section is well accounted for by a directcapture model; that for the γ_{1} capture indicates a nondirect contribution above E(^{3}He) = 10 MeV, interpreted as a resonance due to a state with E_{x} = 25 ± 1 MeV, Γ_{cm} = 4 MeV, T = 1 (because the transition is E1, to a T = 0 final state) [the E1 radiative width M^{2} ≥ 5.2/(2J + 1) W.u.], J^{π} = (2, 3, 4)^{}, α + p + n parentage. The γ_{4} resonance is interpreted as being due to a broad state at E_{x} = 26.6 MeV with T = 0. J^{π} = 3^{} is consistent with the measured angular distribution. The ground and first excited state reduced widths for ^{3}He + t parentage, θ_{0}^{2} = 0.8 ± 0.2 and θ_{1}^{2} = 0.6 ± 0.3: see (1974AJ01). See also (1985MOZZ, 1986MOZQ, 1987MO1I)." Since the previous review (1988AJ01), a new resonance analysis (1988MO1I, 1990HE20, 1990MO10, 1992HE1E) has been applied to the ^{3}He + ^{3}H elastic scattering in odd parity states and to the ^{3}He(^{3}H, γ) data. This analysis explains the shape of the capture cross sections and angular distributions in terms of very wide overlapping resonances. See 6.5 (in PDF or PS). These correspond to ^{6}Li states at E_{x} = 17.985 ± 0.025 MeV, Γ_{cm} = 3.012 ± 0.007 MeV, J^{π} = 2^{}; E_{x} = 24.779 ± 0.054 MeV, Γ_{cm} = 6.754 ± 0.110 MeV, J^{π} = 3^{}; E_{x} = 24.890 ± 0.055 MeV, Γ_{cm} = 5.316 ± 0.112 MeV, J^{π} = 4^{}; E_{x} = 26.590 ± 0.065 MeV, Γ_{cm} = 8.684 ± 0.125 MeV, J^{π} = 2^{} (all with S = 1, T = 1). The analysis is compatible with an almost pure ^{3}He  ^{3}H cluster structure of the negative parity unbound ^{6}Li states with S = 1, T = 1. These results are supported by calculations described in (1995OH03) which utilize a complexscaled ^{3}He + t resonating group method to calculate the energies and widths of the ^{6}Li ^{3}He + t states. Note, however, that the calculated scattering phase shifts rise only gradually with energy and stay well below 90°. Consequently the stated precision on the extracted level parameters is a point of controversy between the authors of (1990MO10, 1990HE20) and one of the authors [H.M.H.] of this review. The radiative capture reaction as a source of ^{6}Li production in Big Bang nucleosynthesis is discussed in (1990FU1H, 1990MA1O, 1997NO04). See also (1995DU12). The angular distribution and polarization of the neutrons in reaction (b) have been measured at E(^{3}He) = 2.70 and 3.55 MeV. The excitation function for E(^{3}He) = 0.7 to 3.8 MeV decreases monotonically with energy. The excitation function for n_{0} has been measured for E(^{3}He) = 2 to 6 MeV and for E(^{3}He) = 14 to 26 MeV; evidence for a broad structure at E(^{3}He) = 20.5 ± 0.8 MeV is reported [^{6}Li*(26.1)]: see (1979AJ01). Angular distributions of deuterons (reaction (c)) have been measured for E_{t} = 1.04 to 3.27 MeV and at E(^{3}He) = 0.29 to 32 MeV. Polarization measurements are reported for E_{t} = 9.02 to 17.27 MeV [see (1979AJ01)], as well as at E(pol. ^{3}He) = 18.0 and 33.0 MeV (1986RA1C). See also (1986KO1K) and (1985CA41). A microscopic calculation for reaction (c) and its inverse with special emphasis on isospin breaking in the analyzing power is described in (1990BR09). See also the calculations of (1990BLZW, 1993DU02, 1993FI06). Elastic scattering (reaction (d)) angular distributions were measured at E(^{3}He) = 5.00 to 32.3 MeV and excitation functions were reported for E(^{3}He) = 4.3 to 33.4 MeV see (1979AJ01). At the lower energies the elastic yield is structureless and decreases monotonically with energy. Polarization measurements were reported for E_{t} = 9.02 to 33.3 MeV. A strong change occurs in the analyzing power angular distributions at E_{t} = 15 MeV. See (1988AJ01) for a description of earlier analyses of these data. More recently a new resonance analysis (1990HE20, 1990MO10) of these same data along with ^{3}He(^{3}H, γ) data led to the ^{6}Li S = 1, T = 1 states discussed above under reaction 3(a). See 6.5 (in PDF or PS). A coupledchannels variational model calculation of the ^{3}He(total) cross section for E_{t} = 9 MeV has been reported by (2001TH12). For other channels see (1984AJ01). See also (1984KR1B). For thermonuclear reaction rates see (1988CA26).
^{6}Li*(0, 2.19) have been populated with reaction (a): see (1974AJ01). See also ^{7}Li (1983CO1E) and (1983FU11). Cross sections for E_{α} < 20 MeV were calculated with a resonating group method by (1991FU02). A kinematically complete experiment on reaction (b) at E_{α} = 67.2 MeV is described in (2000GO35). ^{6}Li excited states at E_{x} = 14.5 and 16.0 MeV with widths ≈ 1 MeV are reported. In a similar experiment (1999GO36) at E_{α} = 67.2 MeV on reaction (c) a ^{6}Li level at E_{x} ≈ 20  21 MeV was reported based on the energy of the final state between ^{3}H and ^{3}He.
Differential cross sections were measured for the transitions to ^{6}Li*(0, 2.19) for E(^{3}He) = 350, 420, 500 and 600 MeV (1983LE26). See also (1984AJ01), (1983BR31, 1983JA13) and (1984GE05). Analyses of data for E(^{3}He) = 295  810 MeV and microscopic reaction model calculations are reported by (1991HA22). See also the calculations of (1999VO01).
The previous review (1988AJ01) summarized the information on this reaction as follows: "No resonance has been observed corresponding to formation of ^{6}Li*(3.56) [0^{+}; T = 1]: the parityforbidden Γ_{α} ≤ 6 × 10^{7} eV (1984RO04)". See also (1984BU01, 1986BU07). "The cross section for the capture cross section has been measured for E_{α} = 3 to 25 MeV by detecting the recoiling ^{6}Li ions: the direct capture is overwhelmingly E2 with a small E1 contribution. The spectroscopic overlap between the ^{6}Li_{g.s.} and α + d is 0.85 ± 0.04: see (1984AJ01). See also (1982KI11), (1985CA41, 1986LA22, 1986LA27) and theoretical work presented in (1984AK01, 1985AK1B, 1986AK1C, 1986BA1R)." Since the previous review (1988AJ01), measurements of the cross section at energies E_{α} ≈ 2 MeV corresponding to the 3^{+} resonance at E_{x} = 2.186 MeV in ^{6}Li have been reported (1994MO17). Values extracted for the total width Γ and the radiative width Γ_{γ} confirm the adopted value (1988AJ01). An experimental search for the reaction at E_{cm} ≈ 53 keV (1996CE02) gave an upper limit for the S factor of 2 × 20^{7} MeV · b at the 90% confidence level. Implications for Big Bang nucleosynthesis of ^{6}Li are discussed. Thermonuclear reaction rates for this reaction calculated from evaluated data are presented in the compilation (1999AN35). A considerable amount of theoretical work has been devoted to this reaction  much of it related to its importance in astrophysics. A list of references with brief descriptions is provided in 6.6 (in PDF or PS).
Reaction (a) has been studied to E_{α} = 165 MeV and to E_{d} = 21.0 MeV: see (1979AJ01, 1984AJ01). Measurements are also reported at E_{d} = 5.4, 6.0 and 6.8 MeV (1985LU08), 6 to 11 MeV (1985OS02), 10.05 MeV (1983BR23) and 12.0 and 21.0 MeV (1983IS10) and at E_{α} = 11.3 MeV (1987BR07). See also (1986DO1K). More recently, measurements of the cross section and transverse tensor analyzing power at E_{d} = 7 MeV were made (1988GA14) with kinematic conditions chosen to correspond to production of the singlet deuteron. Coulomb and nuclear field effects in these reactions are discussed in (1987KO1X, 1988KA38). Cross sections and polarization observables from data at E_{d} < 12, 17 MeV are compared with threebody model predictions in (1988SU12). For reaction (b), measurements of vector and tensor analyzing power at E_{d} = 35, 45 MeV have been reported (1986BR1N, 1986VA23, 1986VUZZ, 1987VU1A). Cross sections and polarization observables were measured at E_{d} = 32.1, 35.15, 39.6, 49.7 MeV to investigate ^{3}H and ^{3}He asymptotic normalization constants (1987VU1B) and charge symmetry breaking (1988VU01). Cross sections and polarization observables measured at E_{cm} = 14  33 MeV (1989BR23) were compared with microscopicmodel predictions in a study of isospin violation. See also (1990BR09). The role of tensor force was explored in (1988BR18). For earlier work and other breakup channels, see (1988AJ01).
Elastic differential crosssection and polarization measurements have been carried out up to E_{α} = 166 MeV and E_{d} = 45 MeV: see (1974AJ01, 1979AJ01, 1984AJ01). Measurements were also reported at E_{d} = 0.87 to 1.43 MeV (1984BA19, 1985BAYZ), at E_{d} = 11.9 MeV (1988EL01), 21 MeV (1986MI1E), 24.0 and 38.2 MeV (1986GR1D), 31.8 to 39.0 MeV (1986KO1M), 40 MeV (1989DE1A), 56 MeV (1985NI01) and at E_{α} = 7.0 GeV/c (1984SA39). A compilation of data for energies E_{d} = 1  56 MeV is presented in (1987GR08). For a study of the inclusive inelastic scattering at E_{α} = 7.0 GeV/c see (1987BA13). Phaseshift analyses, particularly that by (1983JE03) which uses all available differential cross section, vector and tensor analyzing power measurements and L ≤ 5, in the range E_{d} = 3 to 43 MeV lead to the results displayed in 6.7 (in PDF or PS). It is found that the dwave shifts are split and exhibit resonances at E_{x} = 2.19 (^{3}D_{3}), 4.7 (^{3}D_{2}) and 5.65 MeV (^{3}D_{1}). (1983JE03) suggest very broad G_{3} and G_{4} resonances at E_{d} = (19.3) and 33 MeV, a D_{3} resonance at 22 MeV and F_{3} and F_{2} resonances at ≈ 34 and ≈ 39 MeV, corresponding to states which are primarily of (d + α) parentage. (1985JE04) have investigated the points where A_{y}y = 1 and report four such points at E_{d} = 4.30 [θ_{cm} = 120.7°], 4.57 (58.0°), 11.88 (55.1°) and 36.0 ± 1.0 MeV (150.1 ± 0.3°). [For the latter see also (1986KO1M)]. The correspondence of these polarization maxima to ^{6}Li states is discussed by (1985JE04). For a discussion of the Mmatrix see (1988EL01). For work on (α + d) correlations involving ^{6}Li*(0, 2.19, 4.31 + 5.65) see (1987CH08, 1987CH33, 1987PO03) and (1987FO08). For additional references to early work see references cited in (1988AJ01). A considerable body of theoretical work on the ^{4}He + d channel has been done since the previous review (1988AJ01). A list of references with brief descriptions is provided in 6.8 (in PDF or PS).
Angular distributions have been measured at E(^{3}He) = 8 to 18 MeV and E_{α} = 42, 71.7 and 81.4 MeV: see (1974AJ01). More recently, proton polarization was measured as a function of angle at E_{cm} = 12.6 MeV (1989GR02). At E_{α} = 28, 63.7, 71.7 and 81.4 MeV the αspectra show that the sequential decay (reaction (b)) involves ^{6}Li*(2.19) and possibly ^{5}Li: see (1979AJ01). See also the recent theoretical work of (1993GO16) and the multiconfiguration RGM calculations of (1995FU16).
Reactions (a) and (b) have been studied to E_{α} = 158.2 MeV [see (1979AJ01, 1984AJ01)] and at 198.4 MeV (1985WO11). The dependence of the cross section on energy shows that the α + α process does not contribute significantly to ^{6}Li (and ^{7}Li) synthesis above E_{α} = 250 MeV (1985WO11) [and see for additional comments on astrophysical problems]. A more recent measurement of the cross section for reaction (b) (2001AU06, 2001ME13) at E_{α} = 159.3, 279.6 and 619.8 MeV found cross sections which differ significantly from tabulated values commonly used in cosmicray production calculations and lead to lower predicted production of ^{6}Li. For reaction (c) [and excited states of ^{4}He] see (1984AJ01): ^{6}Li*(2.19) is involved in the process.
See ^{6}He, reaction 1.
The (p, n) reaction has been studied in inverse kinematics by ^{1}H(^{6}He, ^{6}Li)n experiments with secondary ^{6}He beams. An experiment utilizing a secondary ^{6}He beam with E(^{6}He) = 42 MeV/A was reported by (1995CO05, 1998CO1M, 1998CO19, 1998CO28). The ^{6}Li ground state and E_{x} = 3.56 MeV state were observed. Angular distributions were reported and the ratio of the cross section for the GamowTeller transition to the ground state and the Fermi transition to the isobaric analog state was measured. The reaction was also studied at E/A = 93 MeV (1996BR30). The 0° ground state cross section was measured to be dσ/dΩ = 43 ± 16 mb/sr. The ratio of GamowTeller to Fermi strength was found to be (87 ± 6)% of that expected from p, n systematics and beta decay. Differential cross sections at E/A = 41.6  68 MeV were measured by (1997CO04) to study the effects of halo structure. Measurements on reactions (a) and (b) utilizing a secondary ^{6}He beam at 36 MeV/A are reported by (2001DE19). The status of theoretical and experimental research on nuclei featuring a twoparticle halo was reviewed in (1996DA31).
A theoretical study in a microscopic threecluster model of the parityviolating α + d decay of the lowest 0^{+} state in ^{6}Li (E_{x} = 3.5629 MeV) is described in (1996CS03). A phase shift analysis of ^{4}He + d was used in a determination of the vertex constant for the ^{6}Li(1^{+}; 0)_{g.s.} → α + d virtual decay by (1992BLZX, 1993BL09, 1997KU14). See also (1990RY07, 1991KR02, 1993BO38).
The previous review (1988AJ01) summarizes the information on these reactions as follows: "The (γ, n) and (γ, Xn) cross sections increase from threshold to a maximum at E_{γ} ≈ 12 MeV then decrease to E_{γ} = 32 MeV: see (1984AJ01) and (1988DI02). (1984DY01) also report a broad peak at 16 MeV. The cross section for photoproton production (reaction (b)) is generally flat up to 90 MeV. [The previously reported hump at E_{γ} ≈ 16 MeV is almost certainly due to oxygen contamination: see (1984AJ01).] See also (1988CA11) and ^{5}He. The cross section for reaction (c) is ≤ q5 μb in the range E_{γ} = 2.6 to 17 MeV consistent with the expected inhibition of dipole absorption by isospin selection rules: see (1966LA04). The onset of quasideuteron photodisintegration between 25 and 65 MeV is suggested by the study of (1984WA18; E_{γ}(bremsstrahlung) = 67 MeV). The 90° differential cross section for reaction (e) decreases monotonically for E_{γ} = 18 to 70 MeV: reaction (e) contributes ≈ 1/3 of the total cross section for ^{6}Li + γ, consistent with a ^{3}H + ^{3}He cluster description of ^{6}Li_{g.s.} with θ^{2} ≈ 0.68. The agreement with the inverse reaction, ^{3}H(^{3}He, γ) [see reaction 3] is good: see (1984AJ01). See also (1986LI1F)." "The absorption cross section has been studied in the range E_{γ} ≈ 100 to 340 MeV; it shows a broad bump centered at ≈ 125 MeV and a fairly smooth increase to a maximum at ≈ 320 MeV: see (1984AJ01). For spallation studies see (1974AJ01, 1984AJ01). For pion production see (1986GL07, 1987GL01) and (1984AJ01)." Since the previous review (1988AJ01) tagged photons were used to study ^{6}Li(γ, p) at θ_{p} = 0° for E_{γ} ≈ 59 and 75 MeV. Strong evidence for the photodeuteron mechanism was found. Measurements made for angles between 30° and 150° (1995DI01) showed most of the strength occurring in threebody breakup channels. Studies at these same energies of the (γ, d) and (γ, t) reaction were reported in (1997DI01). See also (1994RY01). Measurements of ^{6}Li(γ, d) at E_{γ} ≈ 60 MeV indicated strict nonviolation of the isospin selection rule for E1 absorption. The (γ, pn) reaction was also studied at E_{γ} = 55  100 MeV with bremsstrahlung photons and with linearly polarized tagged photons for E_{γ} = 0.3  0.9 GeV. See also (1990RIZX). Linearly polarized photons were used to measure the cross section asymmetry in ^{6}Li(γ, t)^{3}He up to E_{γ} ≈ 70 MeV (1989BU10) and differential cross sections up to E_{γ} ≈ 90 MeV (1993DE07, 1995BU08). Results of a measurement of the absolute total photoabsorption cross section for E_{γ} = 300  1200 MeV are presented in (1994BI06). A list of theoretical references relating to ^{6}Li photonuclear reactions with brief descriptions is provided in 6.9 (in PDF or PS).
The width, Γ_{γ}, of ^{6}Li*(3.56) = 8.1 ± 0.5 eV: see (1974AJ01) and 6.4 (in PDF or PS) in (79AJ01); E_{x} = 3562.88 ± 0.10 keV: see (1984AJ01). See also (1987PI06). The results of an absolute measurement of the total photoabsorption cross section are described in (1994BI06). Photon absorption and photon scattering for light elements is discussed in terms of a collective resonance phenomenon in (1990ZI03).
Measurements of neutralpion photoproduction yield (reaction (a)) for E < 10 MeV above threshold were reported in (1989NA23). The total cross section was measured in the energy region from the reaction threshold to E_{γ} ≈ 146.5 MeV (1989GL07) and analyzed in the impulse approximation. The cross section increases monotonically to σ = 6.50 ± 0.96 μb at E_{γ} = 146.5 MeV. See also (1986GL07, 1987GL01) and (1984AJ01). An analysis (1991TR1C) of early measurements suggests that anomalously large measured values of the cross section are due to target impurities. The differential cross section at small angles at energies E ≈ 300  450 MeV has been measured by (1991BE16). Total and differential cross sections were measured within 23 MeV of threshold with tagged photons by (1999BE14). Differential cross sections for reaction (b) leading to the ^{6}He ground state have been measured at E_{γ} = 200 MeV (1991SH02) and analyzed by DWBA. See also the measurements of (1991GA26). The energy distributions of electroproduced π^{+} at E_{e} ≈ 200 MeV were measured and (γ, π^{+}) cross sections were deduced (1994SH38). For reaction (c) see (1988KA41, 1991GA26). Theoretical studies of pion photoproduction include: an impulseapproximation calculation for (γ, π^{0}) at E_{γ} = 300 MeV (1989TR09); an impulse approximation and shell model study of inelastic photoproduction of pions (1991TR02); a DWIA Feynmandiagram productionoperatorbased calculation of (γ, π^{+}) at E_{γ} = 200 MeV (1990BE49); and multicluster dynamicmodel calculation of π^{+} photoproduction off ^{6}Li (1995ER1B); and an exclusive (γ, π^{+}) production calculation for E_{γ} = 200 MeV (1995DO24).
The previous review (1988AJ01) summarized the information then available on electron scattering as follows: "The elastic scattering has been studied for E_{e} = 85 to 600 MeV: see (1974AJ01, 1979AJ01, 1984AJ01). The results appear to require that the ground state be viewed as an αd cluster in which the deuteron cluster is deformed and aligned. The groundstate M1 current density has also been calculated (1982BE11). A modelindependent analysis of the elastic scattering yields r_{r.m.s.} = 2.51 ± 0.10 fm. See also the discussion in (1984DO20)." 6.10 (in PDF or PS) summarizes the results obtained in the inelastic scattering of electrons. Form factors have been measured for ^{6}Li*(2.19, 3.56, 5.37) as well as for the t + ^{3}He continuum up to 4 MeV above threshold [no narrow structures corresponding to ^{6}Li states are observed]: see (1984AJ01)". In more recent work, nucleon spin structure functions were extracted from measurements of deep inelastic scattering on polarized targets by (1999RO13). For reaction (b) see ^{5}He and (1987VA08) and (1987VA1N). Angular distributions for the d_{0} group in the (e, d_{0}) reaction have been measured for E_{x} = 10 to 28 MeV. The deduced E1 and E2 components of the (γ, d_{0}) cross section show no structure. The E1 strength implies nonnegligible isospin mixing in this energy region (1986TA06). Triple differential cross sections were measured for E_{x} = 27  49 MeV in a search for GDR evidence (1999HO02). At E_{e} = 480 MeV (reaction (c)) the αd momentum distribution in the ground state of ^{6}Li has been studied. The results are well accounted for by an αNN model. The αd probability in the ground state of ^{6}Li is 0.73 [estimated ± 0.1]. The data are consistent with the expected 2S character of the αd relative wave function (1986EN05). See also (1986EV1A). π^{0} production involving ^{6}Li*(2.19, 3.56, 5.37) is reported at E_{e} = 500 MeV (1987NA1I). For the earlier work see (1979AJ01, 1984AJ01) and the references cited in (1988AJ01). Since the previous review (1988AJ01), experimental results on quasielastic response have been reviewed (1988LO1E). Measurements of the quasielastic scattering cross section for electrons on ^{6}Li are reported at momentum transfer 0.85  2.3 fm^{1} (1988BU25). See also the measurements at E_{e} = 80  680 MeV by (1989LI09). Cross sections for ^{6}Li(e, ep) were measured in the missing energy region 0 ≤ E_{m} ≤ 30 MeV and in the range 100 ≤ p_{m} ≤ 200 MeV/c of missing momentum (1989LA22). The ^{6}Li → p + (nα) spectral function was measured (1989LA13). The ratio of transverse and longitudinal response function was investigated in (1990LA06). See also the review (1990DE16) of proton spectral functions and momentum distributions in (e, e'p) experiments and see the report (1990GH1E) on nuclear density dependence of electron proton coupling in ^{6}Li(e, e'p). Reaction (c) was used (1990JO1D) in a study of correlation functions in ^{6}Li. A measurement in parallel kinematics to study the mechanism of the ^{6}Li(e, e'α)^{2}H reaction is reported in (1991MI19, 1994EN04). Cross sections for ^{6}Li(e, e't)^{3}He (reaction (d)) at E_{e} = 523 MeV and the momentumtransfer dependence of the ^{3}H and ^{3}He knockout reaction was measured by (1998CO06). A list of references to theoretical work related to electron scattering on ^{6}Li is provided, along with brief descriptions, in 6.11 (in PDF or PS).
Elastic angular distributions have been measured at E_{π+} ≈ 50 MeV [see (1984AJ01)] and at E_{π±} = 100, 180 and 240 MeV (1986AN04; also to ^{6}Li*(2.19)). Differential cross sections are also reported for E_{π+} = 100 to 260 MeV to ^{6}Li*(0, 2.19, 3.56, 4.25). The excitation function for the unnaturalparity transition to ^{6}Li*(3.56) has an anomalous energy dependence (1984KI16). A number of experimental studies with polarized targets have been reported for elastic and inelastic (E_{x}(^{6}Li) = 2.19 MeV, J^{π} = 3^{+}) scattering. Measurements of polarization observables are reported at E_{π+} = 134, 164 MeV (1989TA21, 1990TA1L, 1991BO1R), E_{π+} = 160  219 MeV (1991RI01, 1994RI06). Comparison of these data with a coupled channels model is discussed in (1995BO1H). See also the Δhole model analysis of (1992JU1B) and the multicluster dynamic model analysis by (1995RY1C). Calculations of cross sections and polarization observables at E_{π+} = 80  260 MeV are presented in (1988ER06, 1988NA06). A theoretical study in terms of a strong absorption model is described in (1998AH06). Quantum MonteCarlo calculations of cross sections for E_{π} = 100  240 MeV are reported in (2001LE01). Transition densities and B(E2) transition strengths were also calculated. Measurements of pion doublecharge exchange cross section (reactions (b) and (c)) at incident pion energies E_{π} = 180, 240 MeV are reported in (1989GR06, 1995FO1J). In (1991SE06) it is shown that continuum missing mass spectra from reaction (c) can be explained in terms of the presence of dineutrons in the products of the breakup. Cross section measurements for reaction (d) at E_{π+} = 130, 150 MeV are reported in (1987HU02). For a study of reaction (i) at E_{π+} = 130 MeV, see (1987HU13). Pion absorption followed by nucleon emission (reactions (e), (f), (g), (h), (j), (k), (l)) has been studied in a number of experiments. For reaction (k) see (1983BA26, 1983LO10, 1985MC05, 1986MC11). Measurements have been reported for cross sections for reaction (g) at E_{π+} = 30, 50, 80, 115 MeV (1989ROZY); reactions (g) and (h) angular distributions at E_{π} = 70, 130, 165 MeV (1989YO05); reactions (g) and (h) angular correlations at E_{π} = 165 MeV (1989YO07); cross sections for reaction (g) at E_{π+} = 115, 140, 165, 190, 220 MeV (1989ZHZZ); angular distributions for reaction (h) at E_{π} = 70, 130, 165 MeV (1989YO03); twoparticle coincidences for reactions (g) and (h) at low energies (1991YO1C); cross sections at E_{π} = 50, 100, 150, 200 MeV (1990RA05, 1990RA20, 1992RA01, 1992RA11); differential and total cross sections for reaction (g) at E_{π+} = 100, 165 MeV (1995PA22, 1996LO04); inclusive spectra of ^{3}He produced in reaction (l) (1992AM1H, 1993AM09); total reaction cross sections for (π^{+}, X), (π^{}, X) at E_{π} = 42  65 MeV (1996SA08). See also the earlier work on reaction (g) at E_{π+} = 59.4 MeV (1986RI01), and see the compilation and review of (1992BA57, 1993IN01). Analysis of particle emission following π^{+} absorption on ^{6}Li (1990RA20) has produced evidence for a threenucleon absorption model. Distortedwave impulse approximation calculations of cross sections and analyzing powers have been made (1992KH04) for twonucleon pion absorption on polarized ^{6}Li targets. A model based solely on isospin was used (1993MA14) in a calculation of ratios of pion absorption on three nucleons and agreement with experiment suggest a onestep process.
Angular distributions involving the groups to ^{6}Li*(0, 2.19) have been reported at E_{n} = 1.0 to 14.6 MeV [see (1984AJ01)], 4.2, 5.4 and 14.2 MeV (1985CH37; n_{0}, n_{1}), 7.5 to 14 MeV (1983DA22; n_{0}), 8.9 MeV (1984FE1A; n_{0}), 8.0 and 24 MeV (1986HAZR; n_{0}, n_{1}), E_{n} = 5 to 17 MeV (1986PF1A; n_{0}), 11.5, 14.1 and 18 MeV (1998CH33; n_{0}, n_{1}), and at 11.5 and 18.0 MeV (1998IB02; n_{0}, n_{1}). An analysis (1988HA25) of (n, n) and (n, n') data at E_{n} = 24 MeV indicated that neutron and proton transition densities were approximately equal (ρ_{n} ≈ ρ_{p}) in ^{6}Li. Cross sections and analyzing powers for E_{n} = 8  40 MeV were analyzed (1989HAZV) with microscopic optical model potentials. Secondary neutron spectra induced by 14.2 MeV neutrons on ^{6}Li were measured by (1993XI04). An analysis of (n, n') data at E_{n} = 7.45  14 MeV is discussed in (1990BE54). See also the calculation for elastic coherent and incoherent scattering of thermal neutrons on ^{6}Li (1990GO26) and the multicluster dynamic model calculation for ^{6}Li(n, n) at E_{n} = 12 MeV (1992KA06). Theoretical studies of ^{6}Li(n, n) include multiconfiguration resonating group calculations (1988FU09, 1991FU02), folding model descriptions for E_{n} = 25  50 MeV (1993PE13), study of antisymmetry in NN potentials (1995CO18), study of optical model potentials for intermediate energies (1996CH33). For reaction (b) see (1984AJ01, 1985CH37, 1993XI04, 1994EL08). A number of experiments on the (n, p) charge exchange (reaction (c)) have been reported. They include: measurements of σ(E_{p}) and σ(θ) at E_{n} ≈ 198 MeV (1987HE22); σ(θ, E_{p}) at E_{n} ≈ 118 MeV (1987PO18, 1988HA12, 1998HA24); σ(θ) at E_{n} = 198 MeV (1988JA01); σ(θ) to explore the GamowTeller sum rule (1988WA24); σ(θ), σ(E_{p}) at E_{n} = 280 MeV for an isospin symmetry test (1990MI10); σ(θ, E) at E_{n} = 60  260 MeV (1992SO02); and polarization observables at E_{n} = 0.88 GeV (1996BB23). For reaction (e), measurements were reported at thermal neutron energies (1994IT04) and at E_{n} < 10 MeV (1994DR11). For reaction (f), measurements of parity violation with cold polarized neutrons are described in (1990VE16, 1993VE1A, 1996VE02). A discussion of nuclear reaction rates and primordial ^{6}Li is presented in (1997NO04). See also the applicationrelated calculation of (1993FA01). Theoretical work related to reactions (b), (c), (d), (e), (f) includes: dynamical clustermodel calculation (1991DA08); microscopic calculation in a 3particle α + 2N model (1993SH1G); supermultipletsymmetryapproximation calculation at E_{n} = 6.77 MeV (1993DU09); multiconfiguration RGM calculation (1995FU16); and threebody cluster model calculations of ^{6}Li(n, p) at E_{n} = 50 MeV (1997DA01, 1997ER05).
Proton angular distributions have been measured for E_{p} = 0.5 to 800 MeV [p_{0}, p_{1}, p_{2}, p_{3}] [see (1966LA04, 1974AJ01, 1984AJ01)] and at E_{p} = 5 to 17 MeV (1986PF1A; p_{0}). Doubledifferential cross sections for the continuum yield [E_{x} = 1.5  3.5 MeV] are reported at E_{p} = 65 MeV (1987TO06). See also (1983GLZZ, 1983PO1B, 1983POZX). More recently differential cross sections and/or polarization observables have been measured at E_{p} = 6  10 MeV (1989HA17) [optical model analysis]; E_{p} = 1.6  10 MeV (1989HA18) [phase shift analysis]; E_{p} = 65, 80 MeV (1989TO04) [DWIA analysis]; E_{p} = 200 MeV (1990GL04); E_{p} = 65 MeV (1992NA02) [microscopic DWBA analysis]; E_{p} = 72 MeV (1994HE11) [depolarization parameters]; E_{p} < 2.2 MeV (1995SK01) [deduced resonance parameters]; E_{p} = 0.88 GeV (1996BB23) [polarized target]; E_{p} = 250  460 keV (1997BR37), E_{p} = 280 MeV (1990MI10) [deduced isospin symmetry test]; E_{p} = 14 MeV [optical model, coupled channels]; E(^{6}Li) = 62, 72, 75 MeV/A, ^{1}H(^{6}Li, p) [neutron halo states] (1996KUZU); E_{p} = 1.6  2.4 GeV (1999BB21, 1999DE47). For a summary of the results on excited states see 6.12 (in PDF or PS). Reaction (b) was studied at 70 MeV (1983GO06), at 50  100 MeV (1984PA1B, 1985PA1B) and 1 GeV (1985BE30, 1988BE2B, 2000MI17): see ^{5}He and (1984AJ01) for the earlier work. Reaction (c) has been studied at E_{p} = 9 MeV to 1 GeV [see (1974AJ01, 1979AJ01, 1984AJ01)] and at 20 and 42 MeV (1983CA13) [report involvement of ^{6}Li*(4.31, 5.65)], at 70 MeV (1983GO06, 1985PAZL, 1985PA04) and at 119.6 and 200.2 MeV (1984WA09, 1985WA25). In the latter experiments the spectroscopic factors for ^{6}Li_{g.s.} are deduced to be 0.76 [at 119.6 MeV] and 0.84 [at 200.2 MeV] using DWIA and a boundstate WoodsSaxon 2S wave function (1984WA09, 1985WA25). Work on reaction (d) has suggested that the ^{3}He + t parentage of ^{6}Li is comparable with the α + d parentage: see (1984AJ01). See also (1985PAZL). Reaction (e) was studied at E_{p} = 70 MeV (1988PA27). See also ^{5}Li, ^{6}Be and (1985BE30, 1993ST06). The (p, 3p) reaction has been studied by (1984NA17). The spectral function for pn pairs in ^{6}Li was obtained in a study of the ^{6}Li(p, pα)pn reaction at E_{p} = 200 MeV (1990WA17). A measurement of tensor analyzing powers in ^{1}H(^{6}Li, d or α or t)X with 4.5 GeV polarized ^{6}Li deuterons provided information on the ^{6}Li D state (1992PU03). Systematic studies of electron screening effects on low energy reactions including ^{6}Li + p are reported in (1992EN01, 1992EN04, 1995RO37). For antiproton studies see (1987AS06). See also (1984AJ01, 1988AJ01) for the earlier work. Theoretical work on these reactions reported since the previous review (1988AJ01) is listed in 6.13 (in PDF or PS) along with brief descriptions.
Angular distributions of deuterons have been measured at E_{d} = 4.5 to 19.6 MeV [see (1979AJ01)] and at 50 MeV (1988KO1C, 1996RU10). The 0^{+}, T = 1 state, ^{6}Li*(3.56) is not appreciably populated. For a summary of the results on excited states see 6.12 (in PDF or PS). Gaussian potentials were derived for the description of ^{6}Li + d elastic scattering by (1992DU07). At E_{d} = 21 MeV reaction (b) shows spectral peaking (characteristic of ^{1}S_{0} for the pn system [T = 1]) when ^{6}Li*(3.56) is formed, in contrast with the much broader shape (characteristic of ^{3}S_{1}) seen when ^{6}Li*(0, 2.19) are populated. A study of reaction (c) at E_{d} = 52 MeV shows that the αclustering probability, N_{eff} = 0.12^{+0.12}_{0.06} if a Hankel function is used. The αparticle and the deuteron clusters in ^{6}Li have essentially a relative orbital momentum of l = 0. The Dstate probability of the ground state of ^{6}Li is ≈ 5% of the Sstate. Quasifree scattering is an important process even for E_{d} = 6 to 11 MeV. Interference effects are evident in reaction (c) proceeding through ^{6}Li*(2.19, 4.31): this is due to the experiment being unable to determine whether the detected particle was emitted first or second in the sequential decay. Reactions (c) and (d) studied at E_{d} = 7.5 to 10.5 MeV indicate that the threebody breakup of ^{6}Li at these low energies is dominated by sequential decay processes (1979AJ01, 1990YA11). Differential cross sections for cluster pickup by 20 MeV/A deuterons on ^{6}Li were measured by (1995MA57). Calculation of Maxwellian rate parameters for reaction (d) and (e) are described in (2000VO08). See also ^{8}Be and references cited in (1988AJ01).
At E_{t} = 17 MeV angular distributions have been measured for the tritons to ^{6}Li*(0, 3.56): see (1979AJ01).
Angular distributions have been measured at E(^{3}He) = 8 to 217 MeV [see (1979AJ01, 1984AJ01)] and at 34, 50, 60 and 72 MeV (1986BR31; elastic). More recently, differential cross sections were measured for elastic scattering at E(^{3}He) = 93 MeV (1994DO32), and at E(^{3}He) = 60 MeV (1995MA57), and for inelastic scattering to ^{6}Li*(E_{x} = 2.185 MeV, J^{π} = 3^{+}) at E(^{3}He) = 50, 60, 72 MeV (1995BU20). A microscopicpotential analysis of data at E(^{3}He) = 34, 50, 60, 72 MeV is described in (1993SI06). Differential cross section and energy spectra were compiled and analyzed by (1995MI16). For reaction (b), cross sections have been measured at E(^{3}He) = 11, 13, 14 MeV (1989ARZR, 1989AR08); E(^{3}He) = 2.5 MeV (1989AR20); E(^{3}He) = 1.6 MeV (1991AR25); E(^{3}He) = 1.6  9 MeV (1992AR20); E(^{3}He) = 8  14 MeV (1995KO51); E(^{3}He) = 2.0, 22 MeV (1992DA1K); E(^{3}He) = 7, 9 MeV (1993AR12). A calculation of nearthreshold twofragment resonance amplitudes and widths for this reaction at E(^{3}He) = 8  14 MeV was reported in (1995KO51). See also ^{5}Li, (1984AR17, 1987ZA07), and ^{9}B in (1988AJ01).
Angular distributions (reaction (a)) have been measured at E_{α} = 1.39 to 166 MeV [see (1974AJ01, 1979AJ01, 1984AJ01)] and at E_{α} = 36.6 and 50.5 MeV (1986BR31). See also (1986ROZK, 1987BU27). See also ^{10}B in (1988AJ01). More recent measurements at E_{α} = 50.5 MeV of elastic and inelastic ^{6}Li*(E_{x} = 2.185 MeV, J^{π} = 3^{+}) were reported by (1994BUZY, 1996BU06). Tensor polarization for inelastic scattering to ^{6}Li*(2.185, 3^{+}) has been measured at E_{α} = 80 MeV (1992KO19, 1993KO33). Angular distributions for (α, α') in the continuum region were studied at E_{α} = 50 MeV (1992SA01) and at E_{α} = 40 MeV (1994SA32), at E_{α} = 10 MeV/A (1996SI13) and at E_{α} = 119 MeV (1993OK1A). Cross sections and analyzing powers for elastic scattering of polarized ^{6}Li by ^{4}He are reported for E(^{6}Li) = 50 MeV (1995KE10) and E_{cm} = 11.1 MeV (1996GR08). Studies of continuum coupling effects in inelastic scattering are described in (1995KA1Y, 1995KA43, 1997RU06, 2000RU03). Foldingmodel potential analyses of elastic scattering are reported in (1993SI09, 1995SA12). Multiconfiguration resonating group methods applied to the ^{6}Li + α system are discussed in (1994FU17, 1995FU11). Other recent theoretical studies include: a potential model description (1999MA02); analysis of density distribution influence (1998GO1J); a phaseshiftanalysis determination of the asymptotic D to Sstate ratio (1999GE02); a calculation for E_{α} = 16.3 and 48 MeV with a modified Volkovpotential (2000KO52); and a calculation of the nuclear potential and polarization tensor for E_{α} = 27.2 MeV (2000KO67). See also (1988KO32, 1989LE07, 1999OG09). Reaction (b) has been studied at E_{α} = 6.6 to 700 MeV: see (1974AJ01, 1979AJ01, 1984AJ01). At the latter energy and using a width parameter of 60.6 MeV/c the effective number of α + d clusters for ^{6}Li_{g.s.}, n_{eff} = 0.98 ± 0.05. The results are very model dependent: see (1984AJ01). At E_{α} = 27.2 MeV ^{6}Li*(2.19) is very strongly populated (1985KO29). See also references cited in (1988AJ01). In more recent work, two dimensional coincidence spectra of charged particles were measured at E_{α} ≈ 100 MeV (1992GA18). Quasifree scattering processes were studied at E_{α} = 77  119 MeV (1992OK01), E_{α} = 118 MeV (1993OK1B), and E_{α} = 118.4 MeV (1997OK01). The fourbody ^{6}Li(α, 2α)pn breakup reaction was measured at E_{α} = 77  119 MeV (1992WA18, breakup cross sections); E_{α} = 118 MeV (1988WA29, 1989WA26; spectral functions of pn pair).
Angular distributions of ^{6}Li ions have been studied for E(^{6}Li) = 3.2 to 36 MeV [see (1974AJ01, 1979AJ01, 1984AJ01)] and at E(^{6}Li) = 2.0 to 5.5 MeV (1983NO08) and 156 MeV (1985SA36; ^{6}Li*(0, 2.19)), (1985MI05; elastic; ^{6}Li*(2.19, 3.56) are also populated), (1987EY01; several states in ^{12}C). Reaction (b) has been studied for E(^{6}Li) = 36 to 47 MeV: enhancements in yield, due to double spectator poles, have been observed in dd and αα but not in αd double coincidence spectra. The widths of the peaks are smaller than those predicted from the momentum distribution of α + d clusters in ^{6}Li. ^{6}Li*(2.19) was also populated. See references in (1984AJ01). Other work on reaction (b) is reported by (1984LA19: 2.4 and 4.2 MeV) and by (1985NO1A). For reaction (c), the energy dependence of quasifree effects were investigated in the range E(^{6}Li) = 2.4  6.7 MeV (1987LA25, 1988LA11). An analysis (1996CH1C) used quasifree data from reaction (c) to extract the ^{6}Li(d, α)^{4}He excitation function at astrophysical energies. See also ^{12}C in (1985AJ01) and references cited in (1988AJ01). More recently, elastic scattering angular distributions were measured for E(^{6}Li) = 5  40 MeV (1997PO03; optical model analysis). Eikonalapproximation calculations of differential cross sections and phase shifts for E(^{6}Li) = 156 MeV were reported in (1992EL1A).
Angular distributions have been measured at E(^{7}Li) = 78 MeV to ^{6}Li*(0, 2.19) (1986GLZU), and at E(^{7}Li) = 9  40 MeV (1998PO03).
The elastic scattering has been studied in inverse kinematics at E(^{6}Li) = 4.0, 6.0 and 24 MeV [see (1979AJ01)], at 32 MeV (1985CO09) and at 50 MeV (1988TRZY; also inelastic). Recently angular distributions for elastic and inelastic scattering to ^{6}Li*(2.186, 3^{+}) were measured (1995MU01) at E_{cm} = 7, 10, 12 MeV. Excitation functions for E_{cm} ≈ 4  12 were also reported. See also ^{9}Be in (1988AJ01). For the interaction cross section at E(^{6}Li) = 790 MeV/A see (1985TA18).
The elastic scattering has been studied at E(^{6}Li) = 5.8 and 30 MeV: see (1979AJ01).
The elastic and inelastic scattering (reaction (a)) has been studied at E(^{6}Li) = 4.5 to 156 MeV [see (1984AJ01)] and at E(^{6}Li) = 19.2 MeV (1983RU09), 36 and 45 MeV [and E(^{12}C) = 72 and 90 MeV] (1984VI02, 1985VI03; also to ^{6}Li*(2.19, 4.31) and to various states of ^{12}C), at E(^{12}C) = 58.4 MeV (1987PA12), 90 MeV (1987DE02; also to various states of ^{12}C), 123.5 and 168.6 MeV (1988KA09; and to various states of ^{12}C), 150 MeV (1987TA21, 1988TA08), 156 MeV (1987EY01; and to various states in ^{12}C) and at 210 MeV (1988NA02). See also (1986SHZP, 1987PA12). More recently, measurements of cross sections and/or analyzing power observables have been reported at E(^{6}Li) = 93 MeV (1989DE34); at E_{cm} = 13.3 MeV ((1989HN1A, 1995CA26) and to ^{6}Li*(3^{+}, 2.186) and ^{12}C*(2^{+}, 4.44)); at E(^{6}Li) = 210 MeV (1989NA11, to ^{12}C*(2^{+}, 4.44)); at E(^{6}Li) = 30 MeV (1989VA04, to ^{12}C*(2^{+}, 4.44)); at 50 MeV (1990TR02, to ^{12}C*(2^{+}, 4.44; 0^{+}, 7.65; 3^{}, 9.64)); at E(^{6}Li) = 30 MeV (1994RE01); at E(^{6}Li) = 30, 60 MeV (1996KE09, to ^{12}C*(2^{+}, 4.44; 0^{+}, 7.65; 3^{}, 9.64)); at E_{cm} = 20 MeV (1996GA29, to ^{6}Li*(3^{+}, 2.18) and ^{12}C*(2^{+}, 4.44)); at E(^{6}Li) = 318 MeV (1993NA01); at E(^{6}Li) = 30 MeV (1994RE15, to ^{12}C*(2^{+}, 4.44; 3^{}, 9.64)); and at E(^{6}Li) = 50 MeV (1995KE10). At E(^{6}Li) = 34 MeV the dα angular correlations involve ^{6}Li*(0, 2.19) (1985CU04). See also (1988SE07), and see ^{12}C in (1985AJ01, 1990AJ01). An experimental study of the α + d breakup in ^{6}Li + ^{12}C collision at E(^{6}Li) = 156 MeV is reported in (1989JE01). For pion production see (1984CH16). For the interaction cross section at E(^{6}Li) = 790 MeV/A see (1985TA18). For VAP measurements at E(^{6}Li) = 30 MeV see (1988VAZY). Fusion cross sections for E(^{6}Li) = 3.11  12.07 MeV are reported by (1998MU12). The elastic scattering (reaction (b)) has been studied for E(^{6}Li) = 5.8 to 40 MeV: see (1984AJ01). Measurements of differential cross sections for E_{cm} = 26 MeV and observations of a nuclear quasi rainbow were reported by (1994DE43). See also (1987CA30, 1988WO10). The elastic scattering (reaction (c)) has been measured for E(^{6}Li) = 93 MeV (1987DE02). See also ^{18}F and ^{19}F in (1987AJ02) and references cited in (1988AJ01). Several theoretical studies relating to ^{6}Li + ^{12}C have been reported. The role of the Pauli Principle in heavy ion scattering has been studied (1988GR32). The dispersive contribution to the ^{6}Li + ^{12}C real potential was estimated (1990KA14). Elastic cross sections for E(^{6}Li) = 30 MeV were analyzed (1990SA05). A semimicroscopic analysis of inelastic scattering at E(^{6}Li) = 156 MeV is described in (1992GA17). Folding model analysis of ^{6}Li + ^{12}C scattering is discussed in (1994NA03, 1994SA10, 1995KH03). Differential cross sections were analyzed with an Smatrix approach by (1998PI02). Other theoretical descriptions of ^{6}Li + ^{12}C scattering are discussed in (1994SA33; strong absorption model), (1995IS1F; multiple diffraction interaction), and (1996CA01; microscopic description).
Elastic angular distributions have been reported at E(^{6}Li) = 4.5 to 50.6 MeV [see (1984AJ01)], at E(^{6}Li) = 35.3 and E(^{16}O) = 94.2 MeV (1984VI02) and at 50 MeV (1988TRZY; also inelastic). At E(^{6}Li) = 25.7 and E(^{16}O) = 68.6 MeV (1984VI01, 1985VI03) report some σ(θ) to ^{6}Li*(2.19) [and to ^{16}O*(6.13)]. See also (1987PA12). See (1985VI03, 1986SC28) for studies of the breakup. Polarization observables have has been measured at E(^{6}Li) = 25.7 MeV, and also using ^{16}O ions (1987VAZY, 1989VA04). Measurements of E(^{6}Li) = 50 MeV for elastic scattering and inelastic scattering to ^{16}O*(2^{+}, 6.05; 3^{}, 6.13; 2^{+}, 6.92; 1^{}, 7.12) were reported (1990TR02). For fusion cross sections see (1986MA19). See also ^{16}O in (1986AJ04), (1986MO1E, 1987PA12) and references cited in (1988AJ01). Theoretical work on this scattering reaction includes: E(^{6}Li) = 29.8 MeV, optical model description (1990SA05); E(^{6}Li) = 29.8  30.6 MeV, Pauli Principle rule (1988GR32); E(^{6}Li) = 30.6, optical model analysis (1990SA05); projectile effects (1991BO48); E(^{6}Li) = 154 MeV, 3body cluster model (1991HI07); E(^{6}Li) = 22.8 MeV, nonresonant breakup states (1991HI11); and E(^{6}Li) = 30 MeV, doublefolding model, role of Pauli Principle (1991SA26).
Elastic scattering for reaction (a) was studied at E(^{6}Li) = 156 MeV (1995DE53). Reaction (c) has been studied at E(^{6}Li) = 88 MeV and 36 MeV (1984AJ01) and at 44 MeV (1989RU05; polarization observables), and E(^{6}Li) = 60 MeV (1994WA20; polarization observables). Reaction (d) was studied at E(^{6}Li) = 156 MeV by (1987NI04; particles and gammas from inelastic scattering). See also the measurements at E(^{6}Li) = 790 MeV/A (1985TA18). Theoretical studies for these reactions include: analyzed nonRutherford cross sections (1991BO48); effects of nonresonant breakup states (1991HI11); strong absorption model analysis (1994SA33); cluster folding interaction (1991HI07); coupled channels study (1992HI02); and clusterfolding analysis (1994RU11).
The elastic scattering has been studied at E(^{6}Li) = 13 to 154 MeV [see (1984AJ01)], at 27 and 34 MeV (1983VI03) and at 210 MeV (1988NAZX). For a study of the decay see (1987NI04). See also references cited in (1988AJ01). More recent measurements have been reported at E(^{6}Li) = 210 MeV (inelastic σ(θ) to ^{28}Si*(first 2^{+} state) (1989NA11); elastic σ(θ), optical parameters (1989NA02); and E(^{6}Li) = 318 MeV (σ(θ), folding model potentials (1990NAZZ, 1993NA01)). Related analyses and other theoretical studies include: Pauli Principle role (1988GR32, 1991SA26); scattering matrix approach (1990KU23); deduced model parameters (1990SA05); nonRutherford cross section thresholds (1991BO48); clusterfolding interactions (1991HI07); energy dependence, dispersion relation (1991TI04); strong absorption model (1994SA33); E(^{6}Li) = 210, 318 MeV, energy approximation (1995EM03); microscopic description (1996CA01); microscopic potentials, density matrix formalism (1996KN02); E(^{6}Li) = 35, 53 MeV/A, breakup effect (1997SA57); and E(^{6}Li) = 210, 315 MeV, Smatrix approach (1998PI02). For reaction (b) see (1987AR13).
Elastic scattering has been studied for E(^{6}Li) = 26 to 99 MeV: see (1984AJ01, 1988AJ01), and at E(^{6}Li) = 34 MeV (reaction (b)) by (1987VA31) and at 210 MeV (1988NAZX, 1989NA02; reaction (b)). ^{6}Li*(2.19) has been studied at E(^{40}Ca) = 227 MeV (1987VA31). Reaction (d) was studied at E(^{6}Li) = 150 MeV (1990KAZH). For fusion measurements (reaction (b)) see (1984BR04). For breakup measurements (reaction (b)) see (1984GR20, 1990YA09, 1992YAZW, 1993GU10, 1995AR15, 1996YA01). For theoretical studies related to these reactions see: energy and target dependence of projectile breakup (1987SA21); sequential breakup cross sections (1987VA31); role of Pauli Principle (1988GR32); exchange effects (1988KH08, 1990DA23); imaginary part of channelcoupling potentials (1990TA1I); E(^{6}Li) = 30 MeV, deduced optical model parameters (1990SA05); cluster folding interactions (1991HI07); strong absorption model (1994SA33); Smatrix approach (1995BE60, 1998PI02); and microscopic potentials (1996KN02). For earlier work see references cited in (1988AJ01).
Transitions to ^{6}Li*(0, 2.19, 3.56) have been observed in reaction (a): see (1979AJ01, 1984AJ01). Differential cross sections are reported for E_{brem} = 60 to 120 MeV for the n_{0} + n_{2} groups (1985SE17). Bremsstrahlung yield for (γ, n_{0}) was measured for E_{γ} = 7  9 MeV (1989KA30). Reaction (b) at 0.9 GeV involves ^{6}Li*(2.19) (1985RE1A). See also the measurements of E_{γ} = 350 MeV reported by (1991GA26), and see ^{7}Li, (1985ST1A, 1986BA2G, 1986GO1M). An analysis of ^{7}Li(γ, n) data in the giant resonance energy region is described in (1987VA05). Cluster effects were explored in (1992VA12). Calculation with a potential two cluster model are reported in (1997DU02).
Quasielastic pionproton backward scattering was measured at E_{π} = 0.7, 0.9, 1.25 GeV (2000AB25). Fermi momentum distributions for ^{6}Li were deduced.
Differential cross sections have been measured at E_{π+} = 75 and 175 MeV for the transitions to ^{6}Li*(0, 2.19): see (1984AJ01). Proton spectra measured at momentum exchange 660 MeV/c (1989LIZO) provided evidence for an ηmeson nuclear bound state.
Angular distributions of deuterons (reaction (a)) have been studied for E_{p} = 167 to 800 MeV [see (1979AJ01, 1984AJ01)] and at 18.6 MeV (1986GO23, 1987GO27; d_{0}, d_{1}, d_{2}; see for spectroscopic factors), 200 and 400 MeV (1985KR13; d_{0}, d_{1}; d_{2} is weakly populated at 200 MeV) and at 800 MeV (1984SM04; d_{0}, d_{1}). The ratio of the intensities of the groups to ^{6}Li*(2.19) and ^{6}Li_{g.s.} increases with energy. It is suggested that this can be understood in terms of a small admixture of 1f orbital in these states (1985KR13). A DWBA analysis of E_{p} = 185 MeV data leads to C^{2}S = 0.87, 0.67, 0.24, (0.05), 0.14, respectively for ^{6}Li*(0, 2.19, 3.56, 4.31, 5.37). No other states were seen below E_{x} ≈ 20 MeV: see (1979AJ01). The tensor analyzing power T_{20} was measured for the ^{1}H(^{7}Li, d)^{6}Li reaction at E(^{7}Li) = 70 MeV to ^{6}Li*(0, 2.186) (1991DA07). Data at E_{p} = 33.6 MeV were analyzed by (1991AB04) in a test for CohenKurath wave functions. See also the analysis of data at E_{p} = 698 MeV by (1993AL05; η production). In reaction (b) at E_{p} = 1 GeV the separation energy between ≈ 6.5 MeV broad 1p_{3/2} and 1s_{1/2} groups is reported to be 18.0 ± 0.8 MeV (1985BE30, 1985DO16). See also (1983LY04, 1988BE1I, 1988GUZW). Differential cross sections were measured at E_{p} = 70 MeV (1988PA26) and at E_{p} = 2.7  3.8 MeV (1988BO37; application). See also the measurements for nuclear microprobe utilization (1995RI14).
A study at E_{d} = 23.6 MeV of the relative cross sections of the analog reactions ^{7}Li(d, t)^{6}Li (to the first two T = 1 states at 3.56 and 5.37 MeV) and ^{7}Li(d, ^{3}He)^{6}He (to the ground and 1.80 MeV excited states) shows that ^{6}Li*(3.56, 5.37) have high isospin purity (α^{2} < 0.008): this is explained in terms of antisymmetrization effects which prevent mixing with nearby T = 0 states: see (1979AJ01). (1987BO39) [E_{d} = 30.7 MeV] deduce that the branching ratio of ^{6}Li*(4.31) [2^{+}] into a dinucleon [T = 1, S = 0] is (85 ± 10)%: see also reactions 21 in ^{6}He and 4 in ^{6}Be. See also (1987GUZZ; E_{d} = 18 MeV; angular distributions to ^{6}Li*(0, 2.19, 3.56)) and (1984BL21, 1986AV01, 1988GUZW). See also the analysis method discussed in (1995GU22; DWBA and dispersive theory).
Angular distributions have been reported at E(^{3}He) = 5.1 to 33.3 MeV [see (1974AJ01, 1984AJ01): the lower energy work has not been published] and more recently at E(^{3}He) = 60 MeV (1994BUZX). Excited states observed in this reaction are displayed in 6.12 (in PDF or PS). See also (1968CO07) which reported observation of ^{6}Li states at 0.0, 2.17 ± 0.02, 3.55 ± 0.02 and 5.34 ± 0.02 MeV. (1986AN04) have analyzed unpublished data which suggest the involvement of several broad highly excited states of ^{6}Li. See also (1987AL23). Several attempts have been made to observe the isospinforbidden decay of ^{6}Li*(5.37) [2^{+}; 1] via ^{7}Li(^{3}He, α)^{6}Li* → d + α: the branching is < 1%. Γ_{p}/Γ = 0.35 ± 0.10 and Γ_{p} + n/Γ = 0.65 ± 0.10 for ^{6}Li*(5.37): see (1979AJ01). ^{4}He + d spectra suggest the excitation of ^{6}Li*(4.3) [E_{x} = 4.3 ± 0.2 MeV, Γ = 1.6 ± 0.3 MeV] and ^{6}Li*(5.7) [E_{x} = 5.65 ± 0.2 MeV, Γ = 1.65 ± 0.3 MeV]: see (1984AJ01). See also (1985DA29, 1988BO1Y). A more recent measurement at E(^{3}He) = 4, 5, 6 MeV (1995AR14) gave values for the width of of ^{6}Li*(4.31) in agreement with the adopted value Γ = 1700 ± 200 keV and found no dependence on incident energy. Measurements of dα coincidence spectra at E(^{3}He) = 11.5 MeV (1988AR20) and 5.0 MeV (1991AR19) gave spectroscopic parameters for ^{6}Li*(5.65) in agreement with adopted values (1988AJ01). At E(^{3}He) = 120 MeV the missing mass spectra for (^{3}He, 2d) and (^{3}He, pt) reflect the population of ^{6}Li*(0, 2.19) and suggest broad structures at E_{x} = 28.5 and 32.9 MeV (1985FR01). See also ^{10}B in (1988AJ01) and (1983KU17, 1988BO1J).
At E(^{6}Li) = 93 MeV a broad group (Γ ≈ 11 MeV) centered at E_{x} = 20 MeV is reported in addition to other peaks at E_{x} = 17.1 ± 0.3, 18.9 ± 0.3 and 21.2 ± 0.3 MeV (1987GLZW). See (1984KO25) for reaction (b).
Cross section measurements were made with virtual photons using electrons at 21.0  39.0 MeV (1999SH05). A compilation and evaluation of cross section data for E_{γ} < 30 MeV has been done by (1999ZHZN).
Angular distributions of αparticles (reaction (a)) have been measured at E_{p} = 0.11 to 45 MeV. [see (1974AJ01, 1979AJ01)] and at E_{p} = 22.5, 31 and 41 MeV (1986HA27; α_{0}, α_{1}, α_{2}; see for spectroscopic factors). See also 6.12 (in PDF or PS) and (1984AJ01). Recent measurements of angular distributions and analyzing power at E_{p} = 77  321 keV are reported by (1998BR10). Measurements at E_{x} = 1 GeV are reported in (2000ANZX). Calculations of the cross section and polarization observables for E_{p} = 40 MeV are reported in (2000GA49, 2000GA59). A study of possible reasons for nonobservation of certain ^{6}Li excited states in the reaction is discussed in (1999TI07). ^{6}Li*(3.56) decays by γemission consistent with M1; Γ_{α}/Γ < 0.025 [forbidden by spin and parity conservation]: see (1984AJ01). An analysis of the ^{9}Be(p, α) cross section at E_{p} = 16  700 keV is described in (2001BA47). Astrophysical Sfactor, analyzing powers and Rmatrix parameters were deduced. At E_{p} = 9 MeV the yield of reaction (b) is dominated by FSI through ^{8}Be*(0, 2.9) and ^{6}Li*(2.19) with little or no yield from direct threebody decay: see (1979AJ01). More recent measurements of cross sections and/or polarization observables have been reported at E_{p} = 50 MeV (1989GU05), E_{p} = 25, 30 MeV (1992PE12; determined spectroscopic strengths), E_{p} = 40 MeV (1997FA17) [see also (1989FA1B)], E_{p} = 2  5 MeV (1988ABZW), E_{p} = 16  390 keV [deduced S(E)] (1997ZA06), E_{p} = 77  321 keV [deduced stellar reaction rates] (1998BR10), E_{p} = 30  300 keV (2000ISZZ). See also applicationrelated experiments (1990RE09, 1995RI14). Analyses of data for this reaction have been reported for E_{p} = 45  50 MeV [DWBA] (1996YA09, 1997YAZV) and E_{p} < 2 MeV [analyzed reaction rates, primordial ^{6}Li] (1997NO04). Reactions (b) and (c) at E_{p} = 58 MeV involve ^{6}Li*(0, 2.19) (1985DE17). See also ^{10}B in (1988AJ01) and (1985MAZG, 1986AN26, 1986KA26).
See ^{5}He.
Angular distributions of ^{6}He_{g.s.} + ^{6}Li_{g.s.} and ^{6}He_{g.s.} + ^{6}Li*(3.56) [both ions listed were detected] have been measured at E_{t} = 21.5 and 23.5 MeV. In the latter case the final state is composed of two isobaric analog states: angular distributions are symmetric about 90° cm, within the overall experimental errors. In the reaction leading to the ground states of ^{6}He and ^{6}Li differences from symmetry of as much as 40% are observed at forward angles. Angular distributions involving ^{6}He_{g.s.} + ^{6}Li*(2.19) and ^{6}Li_{g.s.} + ^{6}He*(1.8) have also been measured. This reaction appears to proceed predominantly by means of the direct pickup of a triton or ^{3}He from ^{9}Be. Differential cross sections are also reported at E_{t} = 17 MeV: see (1984AJ01) for references.
Angular distributions of ^{6}Li ions have been obtained at E(^{3}He) = 6 to 10 MeV: see (1974AJ01). A study of the continuum suggests the population of ^{6}Li states at E_{x} = 8  12, ≈ 21 and 21.5 MeV: see (1984AJ01). More recently, measurements at E(^{3}He) = 60 MeV of differential cross sections have been reported (1990MA1O, 1990MAZG, 1995MA57). Spectroscopic factors were deduced. Angular distributions at E(^{3}He) = 60 MeV for transition to the ^{6}Li ground state and to ^{6}Li*(3^{+}, 2.185; 2^{+}, 5.37; 1^{+}, 5.65) were measured (1996RU13) and analyzed by coupledchannels methods.
Differential cross sections are reported at E_{n} = 14.4 MeV involving ^{6}Li*(2.19) and ^{5}He_{g.s.} (1984TU02).
Angular distributions involving ^{6}Li*(0, 2.19) have been studied at E_{d} = 13.6 MeV (1983DO10) and at 19.5 MeV [see (1974AJ01)]. See also (1984SHZJ).
Angular distributions involving ^{6}Li*(0, 2.19) have been measured at E(^{3}He) = 30 MeV: see (1974AJ01).
At E_{α} = 72.5 MeV only ^{6}Li*(0, 2.19) are observed: the latter is excited much more strongly than is the ground state [S_{α} for the ground state is 0.4 that for ^{6}Li*(2.19)]. The angular distributions for both transitions are flat: see (1979AJ01). See also (1984AJ01). A more recent measurement of differential cross sections at E_{α} = 27.2 MeV is reported in (1995FA21). Spectroscopic factors were deduced.
See (1984AJ01).
Angular distributions are reported at E(^{3}He) = 71.8 MeV involving several states in ^{8}Be (1986JA02, 1986JA14).
Angular distributions involving ^{7}Be*(0, 0.43) have been measured at E_{p} = 40.3 MeV (1985DE05). For the earlier work at E_{p} = 30.6 to 56.8 MeV see (1974AJ01, 1979AJ01). See also references cited in (1988AJ01).
Angular distributions involving states in ^{8}Be have been studied at E_{d} = 19.5 and 51.8 MeV [see (1974AJ01)] and at 50 MeV (1985GO1G, 1989GO07, 1989GO26), 54.2 MeV (1984UM04) and 78 MeV (1986JA14), as well as at E_{d} = 18 and 22 MeV (1987TA07) and 51.7 MeV (1986YA12). See also (1984NE1A, 1987GO1S) and the DWBA calculations at E_{d} = 50 MeV (1988KA46) and E_{d} = 15 MeV (1988RA27).
Angular distributions have been obtained at E(^{3}He) = 28 to 40.7 MeV [see (1974AJ01)] and at E(^{3}He) = 33 MeV (1989SI02), E(^{3}He) = 33.4 MeV (1986CL1B; also A_{y}), E(^{3}He) = 60 MeV (1990MAZG, 1993MA48), E(^{3}He) = 30  60 MeV (1995MA57). See also (1989GL1D) and see ^{9}B in (1988AJ01).
Angular distributions (reaction (a)) at E_{α} = 42 MeV involve ^{6}Li*(0, 2.19): see (1974AJ01). Differential cross sections were measured at E_{α} = 90 MeV and cluster spectroscopic amplitudes were deduced (1991GL03). At E_{α} = 65 MeV reaction (b) goes via ^{6}Li*(2.19, 4.31): see (1984AJ01). See also ^{10}B in (1988AJ01) and (1987GA20).
An analysis involving excited states of ^{6}Li and ^{14}N was applied to cross section and analyzing power data at E(^{6}Li) = 33 MeV by (2000MA43). Measurements of triple differential cross sections for elastic breakup of 156 MeV ^{6}Li (reaction (b)) were reported in (1989HE28, 1989HE17, 1989RE1G). A diffraction dissociation model analysis was used. See also reaction 70. Partial cross sections for the ^{6}Li + ^{12}C reaction were measured for E(^{6}Li) = 3.11  12.07 MeV by (1998MU12).
See ^{16}O in (1986AJ04).
Measurements of angular distributions at E(^{11}B) = 25, 35, 40 MeV have been reported by (1996JA12). Transfer mechanisms were studied.
The fragmentation of ^{12}C into two ^{6}Li ions has been observed at E(^{12}C) = 2.1 GeV/A (1986LIZP).
Angular distributions of reaction products were measured for E(^{14}N) = 50 MeV, and multinucleon transfer mechanisms were studied (1992ARZX). See also the analysis for E(^{14}N) = 54 MeV (1987GO12), and see ^{20}Ne in (1987AJ02, 1998TI06).
See (1974AJ01).
Measurements of differential cross sections and analyzing powers were reported by (1989SI02). Spectroscopic factors were extracted.
Differential cross sections at E(^{3}He) = 60 MeV have been reported (1990MAZG, 1995MA57). Cluster pickup mechanisms were studied.
Angular distributions and polarization observables involving ^{6}Li ions and several ^{12}C states are reported at E_{d} = 22 MeV (1987TA07) and 51.7 MeV (1986YA12) and at E_{d} = 54.2 MeV (1984UM04). See also (1984NE1A), and ^{12}C in (1990AJ01) for polarization studies.
Measurements and analyses of differential cross sections at E(^{3}He) = 30  60 MeV have been reported (1995MA57).
Differential cross sections at E_{d} = 50 MeV were reported (1990GO14).
Angular distributions have been measured at E(^{3}He) = 11 to 40.7 MeV involving ^{6}Li*(0, 3.56) and various states of ^{16}O: see (1974AJ01, 1977AJ02). Differential cross sections have been reported for E(^{3}He) = 66 MeV (1991MA56).
Measurement of the tensor analyzing power made at E(^{6}Li) = 34 MeV (1978VE03) were analyzed to obtain the D and Sstate ratio for the dα^{6}Li bound state overlap.
Angular distributions measured for E(^{6}Li) = 21  32 MeV are reported by (1999MA16).
For reaction (a) differential cross sections were measured at E(^{6}Li) = 25  60 MeV and analyzed by the optical model (1994KE08, 1998KE03). For reaction (b) measurements of triple differential cross sections for elastic breakup of 156 MeV ^{6}Li were reported in (1989HE28, 1989HE17, 1989RE1G). Data were analyzed on the basis of a diffractive disintegration approach. Breakup measurements at E(^{6}Li) = 60 MeV were reported in (1988HE16). See also reaction 56, and see the theoretical study of angular correlation of breakup fragments in (1989BA25).
