
^{8}Be (1979AJ01)(See Energy Level Diagrams for ^{8}Be) GENERAL: See also (1974AJ01) and Table 8.3 [Table of Energy Levels] (in PDF or PS). Shell model: (1973AR1C, 1974KA11, 1975GO07, 1975SC1K, 1976AR07, 1976JI1A, 1976ST04). Collective, rotational and deformed models: (1974BO25, 1974LE04, 1975AR28, 1975KH1A). Cluster and αparticle models: (1970YU02, 1973AB1A, 1973AR1C, 1974CH01, 1974DR05, 1974KA11, 1975AB1E, 1975SC1K, 1976BA1N, 1976ST04, 1977AR08, 1977BE50, 1977FU1D, 1977FU1F, 1977HE10, 1977HE1C, 1977KA1K, 1977KI10, 1977SE1D, 1977SM1A, 1977ZA04, 1978AR1M, 1978ST10, 1978TO09). Special levels: (1973DO1B, 1974HA1G, 1974IR04, 1974KA11, 1974KU06, 1974MC04, 1974NE1B, 1975SH01, 1976IR1B, 1976JI1A, 1977BA62, 1977FU1F, 1977KA1K, 1978AR1M, 1978BA31, 1978BA66, 1978SE1C, 1978SH04, 1978ST10). Electromagnetic transitions: (1974HA1C, 1974KU06, 1976KU07, 1977HE1C, 1977KU20, 1978TO09). Special reactions: (1974GA1E, 1974KO16, 1975FE1A, 1975UN1A, 1976AR02, 1976VA29, 1976WO11, 1977GA1F, 1978ZO1A). Pion and kaon reactions: (1973AR1B, 1973CA1C, 1974AM01, 1974BO1F, 1974ZI1A, 1977BA51). Other topics: (1973DO1B, 1973KR1B, 1973PE05, 1974BE1L, 1974BEYR, 1974CH01, 1974DZ03, 1974IR04, 1974KU06, 1974MC04, 1975AR10, 1975AR28, 1975ER09, 1975GO07, 1975KH1A, 1975KO1C, 1975SH01, 1976AR07, 1976IR1B, 1976KH04, 1976KU07, 1976SA16, 1977AR08, 1977BE1U, 1977HE10, 1977TR07, 1978BA31, 1978JE1B, 1978KA1G, 1978MC04, 1978RO01, 1978RO17, 1978SH04). Ground state of ^{8}Be: (1973AB1A, 1973DO1B, 1973FA1C, 1973PA20, 1973PE05, 1974DR05, 1974DZ03, 1975BE31, 1976BE1G, 1976IR1B, 1976OV1B, 1978RO17).
Γ_{c.m.} for the ^{8}Be_{g.s.} = 6.8 ± 1.7 eV (1968BE02). See also (1974FE1B, 1976FE1A) and (1974LI16; theor.).
The yield of γ_{1} has been measured for E_{α} = 32 to 36 MeV: see (1975NA12, GA77F, 1977PA26). An angular correlation measurement at the resonances corresponding to ^{8}Be*(16.6 + 16.9) [2^{+}; T = 0 + 1] gives δ = 0.19 ± 0.03 (1978BO30); Γ_{γ}(M1) = 6.1 ± 0.53 eV (1978BO30), 7.4 ± 1.0 eV (1977PA26), 5.50 ± 0.60 eV (1977LO1D, 1977LO1E). On the basis of these results there is no evidence for violation of CVC or for the existence of secondclass currents: see (1978BO30). (1977PA26) find E_{x} = 3.18 ± 0.05 MeV for the energy of the first excited state (see also Table 8.4 (in PDF or PS) in (1974AJ01)). The yield of γ_{0} for E_{α} = 33 to 38 MeV is twenty times lower than that for γ_{1}, consistent with E2 decay (1977GAZZ). See also (1975NA1C) and (1977GA1E).
The cross sections for formation of ^{7}Li*(0, 0.48) [E_{α} = 39 to 49.5 MeV] and ^{7}Be*(0, 0.43) [39.4 to 47.4 MeV] both show structures at E_{α} ≈ 40.0 and ≈ 44.5 MeV: they are due predominantly to the 2^{+} states ^{8}Be*(20.1, 22.2). The cross sections for (a) and (b) are of interest in accounting for the abundance of ^{7}Li in the galaxy (1977KI12). Cross sections for p_{0+1} are also reported at E_{α} = 60.2, 92.4 and 140.0 MeV (1975KI14). See also (1977RA1B). The cross section for reaction (c) has been measured at three energies in the range E_{α} = 46.7 to 49.5 MeV (1977KI12). See also (1977KI05). (1976HI04) have measured the excitation functions for p_{0}, p_{2}, d_{0}, d_{1} for E_{α} = 54.96 to 55.54 MeV to study the decay of the first T = 2 state in ^{8}Be: see Table 8.4 (in PDF or PS). See also (1975MA1G), (1977AU1B, 1977KO1J; astrophys.) and ^{6}Li, ^{7}Li and ^{7}Be.
The αα scattering reveals the ground state as a resonance with Q_{0} = 92.12 ± 0.05 keV, Γ_{c.m.} = 6.8 ± 1.7 eV, [τ = (0.97 ± 0.24) × 10^{16} sec] (1968BE02). For E_{α} = 30 to 70 MeV the l = 0 phase shift shows resonant behavior at E_{α} = 40.7 MeV, corresponding to a 0^{+} state at E_{x} = 20.2 MeV, Γ < 1 MeV, Γ_{α}/Γ < 0.5. No evidence for other 0^{+} states is seen above E_{α} = 43 MeV (1972BA83): see also (1974AJ01). The dwave phase shift becomes appreciable for E_{α} > 2.5 MeV and passes through resonance at E_{α} = 6 MeV (E_{x} = 3.18 MeV, Γ = 1.5 MeV, J^{π} = 2^{+}) (1963TO02): see Table 8.4 (in PDF or PS) in (1974AJ01). Five 2^{+} levels are observed from l = 2 phase shifts measured from E_{α} = 30 to 70 MeV: ^{8}Be*(16.6, 16.9) with Γ_{α} = Γ [see (1978HI04) and Table 8.5 (in PDF or PS)], and states with E_{x} = 20.2, 22.2 and 25.2 MeV. The latter has a small Γ_{α} (1972BA83). The l = 4 shift rises from E_{α} ≈ 11 MeV and indicates a broad 4^{+} level at E_{x} = 11.4 ± 0.3 MeV (1959BR71), 11.7 ± 0.4 MeV [Γ = 4.0 ± 0.4 MeV] (1974CH45). A rapid rise of δ_{4} at E_{α} = 40 MeV corresponds to a 4^{+} state at 19.9 MeV with Γ_{α}/Γ ≈ 0.96; Γ < 1 MeV and therefore Γ_{α} < 1 MeV, which is < 5% of the Wigner limit. A broad 4^{+} state is also observed near E_{α} = 51.3 MeV (E_{x} = 25.5 MeV) (1972BA83, 1978LE13). Over the range E_{α} = 30 to 70 MeV a gradual increase in δ_{6} is observed (1972BA83). Some indications of a 6^{+} state at E_{x} ≈ 28 MeV and of an 8^{+} state at ≈ 57 MeV have been reported by (1965DA1A) with Γ_{c.m.} ≈ 20 and ≈ 73 MeV, respectively. A resonance is not observed at the first T = 2 state, ^{8}Be*(27.49): see Table 8.4 (in PDF or PS) (1976HI04). The elastic scattering has also been studied at E_{α} = 160 MeV (1978RO1G), at 650 and 850 MeV (1976FO03), 850 and 1370 MeV (1977TE1A) and at 4.30 and 5.05 GeV/c (1977BE1R, 1977BE1T). The total cross section has been measured at 0.87 and 2.1 GeV/A (1975JA1A). The bremsstrahlung cross section has been measured for E_{α} = 9.35 to 18.7 MeV: see (1974AJ01). See also (1975GR1C; theor.). See also (1975IG1A, 1975TO1A, 1976SL02, 1977KI05, 1978BR1E, 1978CH1G, 1978FI1E) and (1973CO1C, 1973FA1C, 1973HA1F, 1973TA1B, 1974AT1A, 1974BA1P, 1974FR1B, 1974FR06, 1974LU05, 1974RA16, 1974TH04, 1974WA02, 1974WA1D, 1975AN1F, 1975BA76, 1975BE1M, 1975BE16, 1975CL1C, 1975DU09, 1975GR05, 1975GR41, 1975GR1C, 1975HE07, 1975HO1E, 1975KU09, 1975MA27, 1975TA1D, 1976AL1E, 1976BA1E, 1976BR32, 1976CO18, 1976CU07, 1976GO12, 1976HA18, 1976HA1L, 1976HO1A, 1976JA1F, 1976LE1J, 1976LI1E, 1976ME1C, 1976MI17, 1976MO31, 1976RA1E, 1977AL1G, 1977AN1B, 1977BA17, 1977BE50, 1977BU01, 1977CA06, 1977CH1C, 1977DA20, 1977FL13, 1977FR12, 1977FR18, 1977FU1E, 1977HO1D, 1977HO1E, 1977HU1A, 1977IK1A, 1977KO1K, 1977LA1D, 1977MA1J, 1977SA1C, 1977ST1G, 1977TH09, 1977ZA04, 1977ZI01, 1978AR1M, 1978FO1G, 1978FR1F, 1978FR1H, 1978LE13, 1978MA20, 1978NO1B, 1978SA24, 1978SA2B, 1978ST10, 1978TO09, 1978VA03, 1978YA1A; theor.).
The yield of γrays to ^{8}Be*(17.64) [1^{+}; T = 1] has been measured for E_{d} = 6.85 to 7.10 MeV: a resonance is observed at E_{d} = 6962.8 ± 3.0 keV [E_{x} = 27495.8 ± 2.4 keV, Γ_{c.m.} = 5.5 ± 2.0 keV]; Γ_{γ} = 23 ± 4 eV [1.14 ± 0.20 W.u.] for this M1 transition from the first 0^{+}; T = 2 state in ^{8}Be, in good agreement with the intermediate coupling model (1976NO07). The γ_{1} transition from ^{8}Be*(27.49) to ^{8}Be*(2.9) is not observed: assuming Γ_{d0}/Γ = 0.78, Γ^{ΔT} = 2_{γ}/Γ < 2 × 10^{6}. If Γ_{c.m.} = 5.5 keV, Γ^{ΔT} = 2_{γ} < 0.01 eV [< 1.5 × 10^{3} W.u.] for this E2, ΔT = 2 transition (1977LO1F).
The yield curve has been measured for E_{d} = 0.06 to 5.5 MeV and 12 to 17 MeV: see (1974AJ01) and (1977SZ05: 0.10 to 0.18 MeV; activation cross section), (1977EL09: 0.20 to 0.90 MeV; cross sections for n_{0} and n_{1}) and (1974MCZS, 1975MC02: 0.5 to 3.0 MeV; n_{1}γ). Polarization measurements have been reported at E_{d} = 0.27 to 0.60 MeV (1966MI06: n_{1}) and E_{dbar} = 0.6, 0.8 and 1.0 MeV (1977GL05; n_{1}) and at E_{d} = 2.5 to 3.7 MeV (1970TH08; n_{0}, n_{1}). See also ^{7}Be. Comparisons of the populations of ^{7}Be*(0, 0.43) and of ^{7}Li*(0, 0.48) have been made at many energies, up to E_{d} = 7.2 MeV. The n/p ratios are closely equal for analog states, as expected from charge symmetry: see (1974AJ01) and (1977EL09). See also (1973GL1A, 1974AU1B) and (1976MO23, 1977EL11, 1977MC1C; applications).
Excitation functions have been measured for E_{d} = 30 keV to 5.4 MeV: see (1974AJ01). Recent crosssection measurements are reported at E_{d} = 0.1 to 1.0 MeV (1977EL09; p_{0}, p_{1}) and 0.5 to 3.4 MeV (1974MCZS, 1975MC02; p_{0}, p_{1}, p_{1}γ). There is no resonance at E_{d} = 0.4 MeV: see (1976MO23). An anomaly is observed in the p_{1}/p_{0} intensity ratio at E_{d} = 6.945 MeV, corresponding to the first 0^{+}; T = 2 state: E_{x} = 27.483 ± 0.010 MeV, Γ = 10 ± 3 keV, Γ_{p}_{0} << Γ_{p}_{1}, Γ_{p}_{0} < Γ_{d} (1969BL14). See also (1975GE1F). Polarization measurements for p_{0} and p_{1} have been reported at E_{dbar} = 0.6 and 0.96 MeV (1977GL05) and E_{d} = 2.1 to 10.9 MeV (1968DU09, 1968FI07, 1970FI07). The latter report pronounced differences in the angular distributions of the vector analyzing power of the two l_{n} = 1 transitions to ^{7}Li*(0, 0.48). See also ^{7}Li, (1974AU1B, 1978VA1D), (1974AJ01, 1975SE07, 1976MO23) and (1977EL11; applications).
The yield of elastically scattered deuterons has been measured for E_{d} = 2 to 7.14 MeV [see (1974AJ01)]: no resonances are observed, except, possibly, for a very weak anomaly at E_{d} = 6.96 MeV (1975GE1F; abstract). See also ^{6}Li and (1974CH58; theor.).
The cross section for tritium production rises rapidly to 190 mb at 1 MeV, then more slowly to 290 mb near 4 MeV. There is evidence of deviation from isotropy near 0.4 MeV (1955MA20). See also ^{5}Li. For reaction (b) see ^{5}He.
Cross sections and angular distributions (reaction (a)) have been measured at E_{d} = 0.03 to 12 MeV [see (1974AJ01)] and at E_{d} = 0.118 to 0.975 MeV (1977EL09: very accurate total reaction cross sections), 0.50 to 3.4 MeV (1974MCZS, 1975MC02; σ_{R}), 1.0 to 11.5 MeV (1977RI09; σ(θ): see below) and 13.6 MeV (1978FU03; ang. distrib. to ^{4}He*(20.1, 21.1, 25.5)) and E(^{6}Li) = 10 to 31 MeV (1979WA02: 30° yield of α_{0} and α* to ^{4}He*(20.08) [0^{+}]). A critical analysis of the low energy data has led to a calculation of the reaction rate parameter for thermonuclear reactions for plasma temperatures of 2 keV to 1 MeV (1978CL07). Polarization measurements are reported at E_{d} = 0.40 to 11.8 MeV and at E(^{6}Li) = 0.6 MeV [see (1974AJ01)] and at E_{dbar} = 1.5 to 11.5 MeV (1977RI09: vector and tensor analyzing powers). At E_{dbar} = 5, 6, 8 and 9 MeV, A_{yy} = 1 is observed at certain angles: see (1978SE01). Pronounced variations are observed in the cross sections and in the analyzing powers (1977RI09). Maxima are seen at E_{d} = 0.8 MeV, Γ_{lab} ≈ 0.8 MeV and E_{d} = 3.75 MeV, Γ_{lab} ≈ 1.4 MeV (1963ME09, 1964PA06). The 4 MeV peak is also observed in the tensor component coefficients with L = 0, 4 and 8 and in the vector component coefficients: two overlapping resonances are suggested. At higher energies all coefficients show a fairly smooth behavior which suggests that only broad resonances can exist (1977RI09). The results of this and other experiments are in good agreement with the results of (1972BA83) [^{4}He(α, α): reaction 4], that is with two 2^{+} states at E_{x} = 22.2 and 25.2 MeV and a 4^{+} state at 25.5 MeV (1977RI10). A strong resonance is seen in the α* channel [to ^{4}He*(20.08), J^{π} = 0^{+}] presumably due to ^{8}Be*(25.2, 25.5). In addition the ratio of the α*/α differential cross sections at 30° show a broad peak centered at E_{x} ≈ 26.5 MeV (which may be due to interference effects) and suggest a resonancelike anomaly at E_{x} ≈ 28 MeV (1979WA02). See also the discussion in (1974AJ01). At E_{d} = 6.945 MeV, the α_{0} yield shows an anomaly corresponding to ^{8}Be*(27.49), the 0^{+}; T = 2 analog of ^{8}He_{g.s.} (1969BL14) [(1975GE1F; prelim.) find E_{d} = 6962 ± 7 keV, Γ ≈ 10 keV.] For reaction (b) see (1977RO18: E_{d} = 0.465; evidence for QSI) and (1977MI13: E_{d} = 7.5, 9, 10, 10.5 MeV; see ^{5}Li, ^{7}Li). For reaction (c) see (1974AJ01). For reaction (d) see (1977MI13, 1978FU03). See also ^{6}Li. See also (1975GL08, 1975WI25, 1976UL1C, 1978VA1D), (1975SE07, 1977SE1C, 1977SE09, 1978FI1E), (1976MO23, 1977EL11, 1978MO1J; applications) and (1974LI1E; theor.).
Proton groups are observed to ^{8}Be*(0, 2.9, 16.63, 16.92, 17.64): see Tables 8.4 (in PDF or PS) and 8.5 (in PDF or PS) in (1974AJ01). The excitation of ^{8}Be*(18.15, 19.0, 19.4, 19.9) is also reported by (1971GL07). Angular distributions have been measured at E(^{3}He) = 1.4 to 17 MeV [see (1974AJ01)] and at 3, 4.5 and 6 MeV (1976GO1F; p_{0}, p_{1}) and 14 MeV (1977IR01; p_{0}, p_{1}). Reaction (b) proceeds via ^{8}Be*(16.63, 16.92): Γ = 117 ± 10 and 85 ± 10 keV, respectively. Interference effects are reported (1969VI05): see also Table 8.5 (in PDF or PS). See also (1976GO1F, 1977AR09), (1977AS04; theor.) and ^{9}B.
Deuteron groups have been observed to ^{8}Be*(0, 2.9, 11.3 ± 0.4). Angular distributions have been measured at E_{α} = 20 to 48 MeV [see (1974AJ01)] and at E_{α} = 15.8 to 25.1 MeV (1974KO24; d_{0}, d_{1}), 17.3, 23.3, 25.1 MeV (1974LE14; d_{0}, d_{1}), 20 and 24 MeV (1974GR21; d_{0}) and 29.4 MeV (1974MA9; d_{0}, d_{1}). Large differential cross sections at back angles are analyzed by (1974GR21) using both direct and exchange amplitudes. A study of reaction (b) shows that the peak due to ^{8}Be*(2.9) is best fitted by using Γ = 1.2 ± 0.3 MeV (1969BA18): see also Table 8.4 (in PDF or PS) in (1974AJ01). At E_{α} = 42 MeV the αα FSI is dominated by ^{8}Be*(0, 2.9) (1977BO22). See also (1974MA49, 1976LE1K).
This reaction proceeds via ^{8}Be*(0, 2.9, 16.6, 16.9, 22.5), and there is indication also that the direct threebody breakup (reaction (b)) is possible (1971GA21, 1972GA32: E_{max}(^{6}Li) = 13.0 MeV). The involvement of a state at E_{x} = 19.9 MeV (Γ = 1.3 MeV) is suggested by (1966MA40). Good agreement with the shapes of the peaks corresponding to ^{8}Be*(16.6, 16.9) is obtained by using a simple twolevel formula with interference, corrected for the effect of final state Coulomb interaction, assuming Γ(16.6) = 90 keV and Γ(16.9) = 70 keV: see also Table 8.5 (in PDF or PS) (1971NO04). The ratio of the intensities of the groups corresponding to ^{8}Be*(16.6, 16.9) remains constant for E(^{6}Li) = 4.3 to 5.5 MeV: I(16.6)/I(16.9) = 1.22 ± 0.08 (1966MA40, 1966KI09). Partial angular distributions for the α_{0} group have been measured at fourteen energies for E(^{6}Li) = 4 to 24 MeV (1970FR06). See also (1975NO1C; theor.) and (1974AJ01).
Cross sections and angular distributions have been reported from E_{p} = 30 keV to 18 MeV. Gamma rays are observed to the ground (γ_{0}) and to the broad, 2^{+}, excited state at 2.9 MeV (γ_{1}) and to ^{8}Be*(16.6, 16.9) (γ_{3}, γ_{4}). Resonances for both γ_{0} and γ_{1} occur at E_{p} = 0.44 and 1.03 MeV, and for γ_{1} alone at 2, 4.9, 6.0, 7.3, and possibly at 3.1 and 11.1 MeV. In addition broad resonances are reported at E_{p} ≈ 5 MeV (γ_{0}), Γ ≈ 45 MeV, and at E_{p} ≈ 7.3 MeV (γ_{1}), Γ ≈ 8 MeV: see Table 8.6 (in PDF or PS). The E_{p} ≈ 5 MeV resonance (E_{x} ≈ 22 MeV) represents the giant dipole resonance based on ^{8}Be(0) while the γ_{1} resonance, ≈ 2.2 MeV higher, is based on ^{8}Be*(2.9). The γ_{0} and γ_{1} giant resonance peaks each contain about 10% of the dipole sum strength (1976FI1C). The main trend between E_{p} = 8 and 17.5 MeV is a decreasing cross section (1976FI1C). (1977UL02) have studied the analyzing power for E_{pbar} = 0.38 to 0.96 MeV: the data indicate some possibility of a 1^{} state at 17.70 MeV. At the E_{p} = 0.44 MeV resonance (E_{x} = 17.64 MeV) the radiation is nearly isotropic consistent with pwave formation, J^{π} = 1^{+}, with channel spin ratio σ(J_{c} = 2)/σ(J_{c} = 1) = 3.2 ± 0.5 (1961ME10). Radiative widths for the γ_{0} and γ_{1} decay are displayed in Table 8.7 (in PDF or PS). A careful study of the αbreakup of ^{8}Be*(16.63, 16.92) [both J^{π} = 2^{+}] for E_{p} = 0.44 to 2.45 MeV shows that the nonresonant part of the cross section for production of ^{8}Be*(16.63) is accounted for by an extranuclear directcapture process. Resonances for production of ^{8}Be*(16.63, 16.92) are observed at E_{p} = 0.44, 1.03 and 1.89 MeV [^{8}Be*(17.64, 18.15, 18.9)]. The results are consistent with the hypothesis of nearly maximal isospin mixing for ^{8}Be*(16.63, 16.92): decay to these states is not observed from the 3^{+} states at E_{x} = 19 MeV, but rather from the 2^{} state at 18.9 MeV excitation (1969SW01). (1968PA09) find squared T = 1 components of 40% and 60% in ^{8}Be*(16.6, 16.9) and of 95% and 5% in ^{8}Be*(17.6, 18.2). See also (1974SO1D, 1978GO1F, 1978ZI1A; applied work), (1974VA1C; astrophys.) and (1977BA62, 1978BA66; theor.).
Measurements of cross sections have been reported for E_{p} = 1.9 to 52 MeV: see (1974AJ01) and the review article by (1975LI1E). Recent measurements have been carried out at E_{p} = 1.9 to 3.8 MeV (1974BU16: n_{0}; dσ/dΩ(0°)), 4.2 to 25.9 MeV (1976PO06: n_{0}, n_{1}; 3.5°), and for neutron production at 0° at 14.3, 19.4 and 29.6 MeV (1975MC18), 29.4, 39.2 and 50.6 MeV (1976RO10), and 24.7 to 44.7 MeV (1977SC37). Polarization measurements have been reported at E_{p} = 2.05 to 5.5 MeV and 30 and 50 MeV: see (1974AJ01). See also (1976DOZW, 1978LE10). For angular distributions see ^{7}Be. The yield of ground state neutrons (n_{0}) rises steeply from threshold and shows pronounced resonances at E_{p} = 2.25 and 4.9 MeV (1963BO06). The yield of n_{1} also rises steeply from threshold (1964BU08) and exhibits a broad maximum near E_{p} = 3.2 MeV (1961BE05, 1972PR03) and a broad dip at E_{p} ≈ 5.5 MeV, also observed in the p_{1} yield (1972PR03). Multichannel scattering length approximation analysis of the 2^{} partial wave near the n_{0} threshold indicates that the 2^{} state at E_{x} = 18.9 MeV is virtual relative to the threshold and that its width Γ = 50 ± 20 keV (1974AR10). The ratio of the cross section for ^{7}Li(p, γ)^{8}Be*(18.9) γ /→ ^{8}Be*(16.6 + 16.9) [obtained by (1969SW01)] to the thermal neutron capture cross section ^{7}Be(n, γ)^{8}Be*(18.9)γ /→ ^{8}Be*(16.6 + 16.9) [obtained by (1973BA1J)], provides a rough etsimate of the isospin impurity of ^{8}Be*(18.9): σ_{p},γ/σ_{n},γ ≈ 1.5 × 10^{5} and therefore the T = 1 isospin impurity is < 4% in intensity (1974AR10). See, however, (1977BA62; theor.) who estimates ≈ 10% isospin mixing. The structure at E_{p} = 2.25 MeV is ascribed to a 3^{+}, T = (1), l = 1 resonance with Γ_{n} ≈ Γ_{p} and γ^{2}_{n}/γ^{2}_{p} = 3 to 10: see (1966LA04). At higher energies the broad peak in the n_{0} yield at E_{p} = 4.9 MeV can be fitted by J^{π} = 3^{(+)} with Γ = 1.1 MeV, γ^{2}_{n} ≈ γ^{2}_{p} (1963BO06). The behavior of the n_{1} cross section can be fitted by assuming a 1^{} state at E_{x} = 19.5 MeV and a J = 0, 1, 2, positiveparity state at 19.9 MeV [presumably the 20.1  20.2 MeV states reported in reaction 4]. In addition the broad dip at E_{p} ≈ 5.5 MeV may be accounted for by the interference of two 2^{+} states (1972PR03). See Table 8.8 (in PDF or PS). The ratio of the cross sections of the (p, n_{1}) reaction to ^{7}Be*(0.43) to that for the (p, p_{1}) reaction to the analog state ^{7}Li*(0.48) has been measured for E_{p} = 2.4 to 10 MeV and 23 to 52 MeV [see (1974AJ01)] and at E_{p} = 3 to 25.9 MeV (1976PO06): at the lower energies the ratio varies very strongly with energy. [An average value for the ratio over the range 5 to 26 MeV is ≈ 0.3.] See also (1973AT01, 1974AR05, 1976CY1A), (1974LE1E, 1974LO1B, 1975SO1C, 1976RI1B, 1976SL02), (1976BR42, 1976CAZG, 1977LO10, 1977ME1C; applications) and (1974CO1B, 1976AR1F, 1977ST18, 1978BA66, 1978DE37; theor.).
Absolute differential cross sections for elastic scattering have been reported for E_{p} = 0.4 to 12 MeV and at 14.5, 20.0 and 31.5 MeV. The yields of inelastically scattered protons (to ^{7}Li*(0.48)) and of 0.48 MeV γrays have been measured for E_{p} = 0.8 to 12 MeV: see (1974AJ01). (1976SOZW; prelim.) reports total crosssection meeasurements at E_{p} = 25, 30, 35, 40, 45 and 48 MeV. Polarization measurements have been reported at E_{p} = 0.67 to 10.6 MeV and at 14.5, 49.8, 152 and 155 MeV: see (1974AJ01). The polarization has also been studied by (1974DE45; p_{0}) for E_{p} = 1.8 to 3.0 MeV. For angular distribution see ^{7}Li. Anomalies in the elastic scattering appear at E_{p} = 0.44, 1.03, 1.88, 2.1, 2.5, 4.2 and 5.6 MeV. Resonances at E_{p} = 1.03, 3 and 5.5 MeV and an anomaly at E_{p} = 1.88 MeV appear in the inelastic channel. A phaseshift analysis and a review of the existing crosssection data by (1973BR13) show that the 0.44 and 1.03 MeV resonances are due to 1^{+} states which are a mixture of ^{5}P_{1} and ^{3}P_{1} with a mixing parameter of +25°; that the 2^{} state at the neutron threshold (E_{p} = 1.88 MeV) has a width of about 50 keV [see also reaction 16]; and that the E_{p} = 2.05 MeV reosnance corresponds to a 3^{+} state. The anomalous behavior of the ^{5}P_{3} phase around E_{p} = 2.2 MeV appears to result from the coupling of the two 3^{+} states [resonances at E_{p} = 2.05 and 2.25 MeV]. The ^{3}S_{1} phase begins to turn positive after 2.2 MeV suggesting a 1^{} state at E_{p} = 2.5 MeV (1973BR13): see Table 8.9 (in PDF or PS), (1972PR03) and (1977BA62, 1978BA66; theor.). The polarization data of (1974DE45) show structures at E_{p} = 1.9 and 2.3 MeV. See also (1974AR10, 1976MA64). An attempt has been made to observe the T = 2 state [^{8}Be*(27.47)] in the p_{0}, p_{1} and p_{2} yields. None of these shows the effect of the T = 2 state. Table 8.4 (in PDF or PS) displays the upper limit for Γ_{p0}/Γ (1976HI04). See (1973GO41, 1978FR12), (1976IK01) and (1975MA1H, 1977ST18, 1978DE37; theor.).
The excitation function for d_{0} measured for E_{p} = 11.64 to 11.76 MeV does not show any effect from the T = 2 state [^{8}Be*(27.47)] (1976HI04). See also ^{6}Li.
The cross section follows the expression E^{1}e^{B/√E (square root of E)}, with B = 91.5 ± 4.5 keV^{1/2}, in the range E_{p} = 23 to 50 keV. The cross section in that interval rises from 0.013 to 2.4 μb (1967FI05). Taking into account ^{8}Be J^{π} = 2^{+} levels at 16.7, 16.9 and 20.6 MeV, (1972BA41) has made an Rmatrix fit to the revised data of (1971SP05) for E_{p} = 131 to 561 keV and has obtained a quadratic energy dependence for the Sfactor: S = 0.065[1 + 1.82E  2.51E^{2}] MeV · b, over the energy range E_{p} = 0 to 600 keV. Excitation functions and angular distributions have been measured at many energies in the range E_{p} = 23 keV to 45.2 MeV: see (1966LA04, 1974AJ01). Recent measurements include those of (1976SAZR: 1.6 to 12.0 MeV) and (1976HI04: 11.64 to 11.76 MeV). Polarization measurements have been carried out for E_{p} = 0.8 to 10.6 MeV: see (1974AJ01). In the range E_{p} = 3 to 10 MeV the asymmetry has one broad peak in the angular distribution at all energies except near 5 MeV; the peak value is 0.98 ± 0.04 at 6 MeV and is essentially 1.0 for E_{p} = 8.5 to 10 MeV (1968PL01, 1969KI04) [see Fig. 12 in (1969KI04) and Fig. 6 (1968PL01) for contour maps of the asymmetry]. Broad resonances are reported to occur at E_{p} = 3.0 MeV [Γ ≈ 1 MeV] and at ≈ 5.7 MeV [≈ 1 MeV]. Structures are also reported at E_{p} = 6.8 MeV and at E_{p} = 9.0 MeV: see (1974AJ01) and (1976SAZR). The 9.0 MeV resonance is also reflected in the behavior of the A_{2} coefficient (1968PL01). The experimental data on yields and on polarization have been analyzed by (1971KU10): the data appear to require including two 0^{+} states [at E_{x} ≈ 19.7 and 21.8 MeV] with very small αparticle widths, and four 2^{+} states [at E_{x} ≈ 15.9, 20.1, 22.2 and 25 MeV]. See however reaction 4 and (1972BA83). A 4^{+} state near 20 MeV was also introduced in the calculation but its contribution was negligible. The observed discrepancies are said to be probably due to the assumption of pure T = 0 for these states (1971KU10). At E_{p} = 11.64 to 11.76 MeV the excitation function does not show any effect due to the T = 2 state at E_{x} = 27.47 MeV (1976HI04). For a study of spallation see (1976KO03) and (1978FI1E). See also (1974VA33), (1978PR1B; applied) and (1974LO1B, 1975CI1A; theor.).
The population of ^{8}Be*(0, 2.9, 16.6, 16.9, 17.6, 18.2, 18.9, 19.1, 19.2) has been reported in reaction (a): for the parameters of ^{8}Be*(2.9) see Table 8.4 (in PDF or PS) in (1974AJ01). Angular distributions of n_{0} and n_{1} have been reported at E_{d} = 0.7 to 3.0 MeV [see (1974AJ01)] and at E_{d} = 15.25 MeV (1975AZ02; also n to ^{8}Be*(16.6 + 16.9); spectroscopic factors). The angular distributions of the neutrons to ^{8}Be*(16.6, 17.6, 18.2) are fit by l_{p} = 1: see (1974AJ01). See also (1978BA66; theor.). Reaction (b) appears to proceed primarily via ^{8}Be*(2.9, 16.6, 16.9) and ^{5}He_{g.s.}: see (1974AJ01). However, ^{8}Be*(11.4) may also be involved [E_{x} = 11.4 ± 0.05 MeV, Γ_{c.m.} = 2.8 ± 0.2 MeV (1969HO11), 3.4 ± 0.1 MeV (1976FO21)] as may state(s) at E_{x} ≈ 20 MeV (1978AR10). Attempts to observe nα rescattering ("proximity scattering") proceeding via ^{8}Be*(16.6, 16.9) have been unsuccessful: see (1974AJ01). See, however, (1975GR43). See also (1973HU12, 1974DA28, 1974GR44, 1975DA15, 1977LO10), (1976EA1A, 1976NE1B; applications) and ^{5}He and ^{9}Be.
See (1975JE04).
Deuteron groups are observed to ^{8}Be*(0, 2.9, 16.6, 16.9, 17.6). For the parameters of ^{8}Be*(2.9) see Table 8.4 (in PDF or PS) in (1974AJ01). The J^{π} = 1^{+} mixed isospin states have been studied by (1967MA12): see Table 8.5 (in PDF or PS). Angular distributions have been measured at a number of energies in the range E(^{3}He) = 0.9 to 24.3 MeV [see (1974AJ01)] and at 1.2 to 2.5 MeV (1975BO56, 1977BO29). For reaction (b) see (1976DA24). See also (1977SL1B), (1974AL07), (1975KU27, 1975TR02, 1976KU07, 1977BA62; theor.) and ^{9}Be.
Angular distributions have been measured up to E_{α} = 50 MeV [see (1966LA04, 1974AJ01)] and at 23.2 and 25.0 MeV (1974DM01; t_{0}, and t_{1} at higher energy) and 29.4 MeV (1974MA49; t_{0}, t_{1}). The ground state of ^{8}Be does decay isotropically in the cm system: J^{π} = 0^{+} (1970LA14). At E_{α} = 10 MeV an anomaly ("ghost") is observed at E_{x} ≈ 0.5 MeV: see (1971BE52) and reaction 31. Sequential decay (reaction (b)) is reported at E_{α} = 50 MeV via ^{8}Be*(0, 2.9, 11.4, 16.6, 16.9, 19.9) (1970LA14). See also (1974MA49). See also (1976LE1K) and (1977BE51; theor.).
At E(^{7}Li) = 1.4, 1.7 and 1.8 MeV, the angular distributions of ^{6}He ions leaving ^{8}Be in its ground and 2.9 MeV states are essentially isotropic (1968ST12).
At thermal energies, the (n, p) cross section is (4.8 ± 0.9) × 10^{4} b (1973MU14), the (n, α) cross section is ≤ 0.1 mb and the (n, γα) cross section is 155 mb (1963BA34). These values, and comparison of the (p, n) cross section with that of reaction (a), support the J^{π} = 3/2^{} assignment for ^{7}Be(0) (1957NE22, 1963BA34). See also (1974AJ01) and (1977BA62; theor.).
^{8}Be*(0, 2.9) is populated in this reaction at E_{d} = 0.8 to 1.7 MeV. See also Table 8.4 (in PDF or PS) in (1974AJ01).
^{8}Li decays mainly to the broad 2.9 MeV, 2^{+} level of ^{8}Be, which decays into two α particles. Both the βspectrum and the resulting αspectrum have been extensively studied. There appears to be an increasing excess of αparticles with E_{α} which may reflect transitions into the tail of the J^{π} = 2^{+} level at E_{x} = 16.63 MeV. See (1955AJ61, 1966LA04) for earlier references. See also ^{8}B(β^{+}). Studies of the distribution of recoil momenta and neutrino recoil correlation indicate that the decay is overwhelmingly GT, axial vector [see reaction 1 in ^{8}Li] and that the ground state of ^{8}Li has J^{π} = 2^{+}: see (1966LA04). Angular correlations have been measured for the decays of ^{8}Li and ^{8}B as a test of the conserved vector current theory of βdecay. The values of the coefficients are displayed in Table 8.10 (in PDF or PS) (1962NO02, 1963GR11, 1966EI02, 1975TR06). The experimental value of δ [δ ≡ B(^{8}Li)  B(^{8}B)] is (5.4 ± 0.4) W_{β}, consistent with CVC theory (1966EI02). There is no evidence for second class currents in this decay: see, e.g., (1975TR06). See also (1973AN11, 1974TR01, 1978FO1H, 1978HA1K, 1978MC1E), (1973BR1C, 1975CA1F, 1976CA1E, 1977GA1E, 1978BO30) and (1973KU1D, 1973TA30, 1974HO1D, 1974KU06, 1975KR14, 1975WI1E, 1976KU1B, 1977KU1E, 1977KU20, 1977OK1A, 1977SA23, 1977TE1B, 1977WI02, 1978KH03; theor.).
The decay proceeds mainly to ^{8}Be*(2.9) [see Table 8.4 (in PDF or PS) in (1974AJ01) for its parameters]. Detailed study of the high energy portion of the αspectrum reveals a maximum near E_{α} = 8.3 MeV, corresponding to transitions to ^{8}Be*(16.63), for which parameters E_{x} = 16.67 MeV, Γ = 150 to 190 keV or E_{x} = 16.62 MeV, Γ = 95 keV are derived. log ft = 2.9 (1964MA35), 3.33 (1969BA43). The log ft value is consisatent with the identification J^{π} = 2^{+}, T = 1 for ^{8}Be*(16.63) (1964MA35) [actually this state is of mixed T = 0 and 1 isospin]. The energy distribution of αparticles has also been measured by (1969CL10). Analysis of this data and of data from αα scattering in a three level Rmatrix formalism indicate a 2^{+} state of ^{8}Be at E_{x} = 12.0^{3.0}_{+3.5} MeV and of Γ = 14^{3}_{+4} MeV (a_{2} = 6.0 ± 0.5 fm) (1969CL10). For angular correlation measurements see reaction 28 and Table 8.10 (in PDF or PS) (1962NO02, 1966EI02, 1975TR06). See also (1974TR01). There is no evidence for secondclass currents in this decay: see, e.g., (1975TR06). See also (1973BR1C, 1975CA1F, 1976CA1E, 1977GA1E, 1978BO30) and (1974HO1D, 1974KU06, 1975KR14, 1975WI1E, 1976KU1B, 1976KU07, 1977KU1E, 1977OK1A, 1977TE1B, 1977WI02, 1978KH03; theor.).
Neutron groups to ^{8}Be*(0, 2.94) have been studied for E_{γ} = 18 to 26 MeV (1977BU02). See also (1974AJ01) and ^{9}Be. Reaction (b) appears to proceed largely via excited states of ^{9}Be with subsequent decay mainly to ^{8}Be*(2.9): see (1966LA04, 1974AJ01), ^{9}Be and ^{10}Be. Reaction (c) has been studied at E_{p} = 45 and 47 MeV: the reaction primarily populates ^{8}Be*(0, 2.9) (1977WA05). See also (1977JE01, 1978CH07), ^{9}Be and ^{9}B. For reactions (d) and (e) see (1974AJ01) and ^{9}Be. For reaction (e) see (1974GR42).
Angular distributions of deuteron groups have been reported at E_{p} = 0.11 to 185 MeV [see (1974AJ01)] and at E_{p} = 4.6 MeV (1974YA1C; d_{0}), 17.7 MeV (1977GU14; d_{0}, d_{1}) and E_{pbar} = 15 MeV (1976DA15; d_{0}, d_{1}). In the latter work S for ^{8}Be*(0, 2.9) are 0.80 and 1.05 (see also reaction 32) (1976DA15). For other work on spectroscopic factors see (1974AJ01). Besides ^{8}Be*(2.9) [see Table 8.4 (in PDF or PS) in (1974AJ01)] ^{8}Be*(11.4, 16.6, 16.9, 17.6, 18.2, 18.9, 19.2, (20.0), 21.5, 22.0, 23.0, (24.5), 26.0) are populated. See also Table 8.5 (in PDF or PS). (1969SU02) report E_{x} = 11.3 ± 0.3 MeV for the 4^{+} state. At E_{p} = 46 and 100 MeV the angular distributions to ^{8}Be*(16.9, 17.6, 18.2, 19.1) are consistent with l = 1 (1967VE01, 1968LE01, 1971SC26). An anomaly has been reported in deuteron spectra between the d_{0} and d_{1} groups. At E_{p} = 39.9 MeV it is seen at E_{x} ≈ 0.6 MeV. An Rmatrix analysis using a threelevel approximation for both the 0^{+} and the 2^{+} contributions shows that the anomaly is due to a "ghost" of the 0^{+} state which produces the ground state group (1976BA67). See (1974AJ01) for the earlier work. Reaction (b) at E_{p} = 9 MeV is dominated by strong FSI through ^{8}Be*(0, 2.9) and ^{6}Li*(2.19) with little or no yield from a direct threebody decay (1971EM01). See also (1974AD1B, 1974LO1B), (1978PR1A; applied) (1976BO15, 1978BA66; theor.) and ^{10}B.
Angular distributions have been measured for E_{d} = 0.3 to 20 MeV [see (1966LA04, 1974AJ01)] and at 0.15 to 2.5 MeV (1974CH1L; t_{0}), 0.6 to 2.2 MeV (1974FR02; t_{0}), 0.9 to 2.5 MeV (1974BO42, 1975BO1C; t_{0}), 0.9 to 3.1 MeV (1975ZW01; t_{0}), 12.35 and 14.06 MeV (1978TA04; t_{0}, t_{1}), 13.6 MeV (1973ZA06; t_{0}), 28.0 MeV (1977OO01: see below) and at E_{dbar} = 15 MeV (1976DA15; t_{0}, t_{1}; S = 0.37, 0.55: see also reaction 31). At E_{d} = 27.97 MeV angular distributions of triton groups to ^{8}Be*(16.6, 16.9, 17.6, 18.2, 19.1, 19.2, 19.8) have been analyzed using DWUCK: absolute C^{2}S are 0.074, 1.56, 0.22, 0.17, 0.41, 0.48, 0.40, respectively. See also Table 8.5 (in PDF or PS). An isospin amplitude impurity of 0.21 ± 0.03 is found for ^{8}Be*(17.6, 18.2) (1977OO01). See also ^{9}Be(d, ^{3}He) [reaction 18] in ^{8}Li and (1978BA66; theor.). A kinematically complete study of reaction (b) at E_{d} = 26.3 MeV indicates the involvement of ^{8}Be*(0, 2.9, 11.4, 16.9, 19.9 + 20.1) (1973SO08). See also (1974SO1C, 1975DO04, 1975ZA06, 1976HE1F), (1974AJ01) and ^{11}B in (1980AJ01).
Angular distributions have been measured in the range E(^{3}He) = 3.0 to 26.7 MeV [see (1974AJ01)] and at E(^{3}He) = 1.75, 2.12, 2.43 and 2.95 MeV (1974SA1K; α_{0}), 4, 5 and 7 MeV (1975BI14: to ^{8}Be*(17.6, 18.2)), 4 to 7 MeV (1978BI15; α_{0}), 9 and 10 MeV (1975RO09; α_{0}) and at E(^{3}Hebar) = 33.3 MeV (1976KA23: to ^{8}Be*(16.9, 17.6, 19.2)) [S = 1.74, 0.72, 1.17, assuming mixed isospin for ^{8}Be*(16.9)]. The parameters of observed states are displayed in Table 8.4 (in PDF or PS) of (1974AJ01) and Table 8.5 (in PDF or PS) here. In a recent experiment (1974CA32) suggest E_{x} = 2.80 ± 0.05 and 11.8 ± 0.5 MeV for the first two excited states of ^{8}Be. In addition to three relatively sharp states reported in the range 22 < E_{x} < 23 MeV [see Table 8.5 (in PDF or PS)] (1976AJ01) suggest the possibility of a broad state at E_{x} ≈ 25 MeV. See also (1978BA66; theor.). Reaction (b) has been studied at E(^{3}He) = 3.0 and 4.0 MeV (1966SU04, 1968MO05, 1972TA04, 1975KA05) and at 2.9 to 10 MeV (1975RO09). See also (1976AR11). The reaction proceeds via ^{8}Be*(0, 2.9, 11.4, 16.6, 16.9, 19.9, 22.5) (1972TA04). See, however, (1975RO09): Γ_{c.m.} for ^{8}Be*(2.9) is reported to be 0.94 ± 0.04 MeV. J^{π} = 2^{+} is indicated for ^{8}Be*(16.6, 16.9) (1966SU04, 1968MO05). See also (1976STYX), (1976RO1L) and ^{12}C in (1980AJ01).
At E(^{6}Li) = 5.5 and 6.5 MeV angular distributions involving ^{8}Be_{g.s.} and ^{7}Li*(0, 0.48) have been measured (1974VO06). For reaction (b) see (1974KE1C). For reaction (c) see (1977UH1A, 1978CH02). For reaction (d) see (1975SE03, 1975SE04). Reaction (e) has been studied at E(^{18}O) = 16 and 20 MeV (1971KN05). See also (1974AJ01) for the earlier work.
At E_{p} = 34 MeV tritons are observed to the first T = 2 state, E_{x} = 27.4922 ± 0.0026 MeV, Γ_{c.m.} = 12 ± 3 keV: the angular distributions for the transitions to this state and to ^{8}Li*(10.82), reached in the (p, ^{3}He) reaction, are very similar. They are both consistent with L = 0 using a DWBA (LZR) analysis (1975RO01). The particle decay of the T = 2 state has been studied by (1975ADZV; abstract).
See ^{10}B.
Using stopped pions, ^{8}Be states at ≈ 3 and ≈ 19 MeV are populated. The 19 MeV structure may be due to a superposition of three peaks at 17, 19 and 22 MeV (1977BA51).
Angular distributions have been measured at E_{n} = 14.4 MeV (1964VA14; t_{0}, t_{1}). See also (1974TU1A). For reaction (b) see (1967VA12). See also ^{11}B in (1980AJ01).
At E_{p} = 39.4 MeV angular distribution measurements have been carried out for the ^{3}He groups to ^{8}Be*(0, 2.9, 16.6, 16.9): the ratio dσ(16.63)/dσ(16.91) has a mean value of 0.65 ± 0.05 for θ = 15° to 30°, suggesting possibly a preferential excitation of the T = 1 components of these two states. The ratio of the differential cross sections dσ(p, t) [to ^{8}B_{g.s.}] to dσ(p, ^{3}He) [to ^{8}Be*(16.63, 16.92)] (15° to 30°) seems to also suggest this (1971SQ01).
Angular distributions have been reported at E_{d} = 0.5 to 7.5 MeV [see (1974AJ01)] and at E_{d} = 0.8 to 9.0 MeV (1978BU04), 1.83 MeV (1974LA29; α_{0}, α_{1}) and 5 MeV (1975RO09; α_{0}). At E_{d} = 7.5 MeV the total cross section for formation of ^{8}Be*(16.63), σ_{t}(16.63), is about 1.15σ_{t}(16.92), consistent with the mixed isospin character of these two states. σ_{t}(18.15) is ≈ 0.85σ_{t}(16.92), but the other nearby 1^{+} state ^{8}Be*(17.64) has σ_{t}(17.64) ≈ 0.07σ_{t}(16.92), consistent with the nearly pure T = 1 nature of ^{8}Be*(17.64) (1966BR08). These four states [^{8}Be*(16.63, 16.92, 17.64, 18.15)] have been studied for E_{d} = 4.0 to 12.0 MeV. Interference between the 2^{+} states [^{8}Be*(16.63, 16.92)] varies as a function of energy. The crosssection ratios for formation of ^{8}Be*(17.64, 18.15) vary in a way consistent with a change in the population of the T = 1 part of the wave function over the energy range: at the higher energies, there is little isospin violation. At higher E_{x} only the 3^{+} state at E_{x} = 19.2 MeV is observed, the neighboring 3^{+} state at E_{x} = 19.07 MeV is not seen (1970CA12). There is some question as to whether a twolevel fit can be made for the α groups to ^{8}Be*(16.63, 16.92). ((1970CA12) and W.D. Callender, private communication) are dubious about this, feeling that other 2^{+} states have to be brought into the calculation. Based onn a twolevel fit they find the following average values: Γ_{16.6} = 113 keV, Γ_{16.9} = 80 keV, ΔQ = 302 keV. However, (1971NO04) state that the twolevel fit is appropriate of the spectra are properly corrected for effects of final state Coulomb interactions: Γ_{16.6} = 90 ± 5 keV, Γ_{16.9} = 70 ± 5 keV, ΔQ = 290 ± 7 keV: see (1978HI04) and Table 8.5 (in PDF or PS). See also Table 8.4 (in PDF or PS) in (1974AJ01) and (1977BA62, 1978BA66; theor.). Reaction (b) [E_{d} < 5 MeV] takes place mainly by a sequential process involving ^{8}Be*(0, 2.9, 11.4, 16.6, 16.9): see (1975RO09, 1975VA04) and the earlier work in (1974AJ01). See also (1970HU1B, 1976GR22, 1977LA13, 1977NO10), (1974AD1B), and ^{12}C in (1980AJ01).
At E(^{3}He) = 2.45 and 6.00 MeV this reaction proceeds primarily by sequential decay via ^{8}Be*(0, 2.9) and via ^{5}Li, ^{9}B and ^{12}C states (1966WA16).
Angular distributions have been obtained at E_{α} = 46 MeV for the transitions to ^{8}Be*(0, 2.9) (1970ZE03). See also ^{6}Li (1974WO1C, 1976WO11).
Angular distributions have been obtained at E(^{7}Li) = 24 MeV to ^{8}Be*(0, 2.9, 11.4) (1977KO27).
See ^{11}B in (1980AJ01).
Angular distributions have been measured at E_{p} = 0.78 to 45 MeV [see (1974AJ01)] and at E_{p} = 5.08 to 38 MeV (1975BU1B, 1978BU1D; α_{0}) and 7.3 MeV (1974KA1J; α_{0}, α_{1}). Observed parameters for ^{8}Be*(2.9) are shown in Table 8.4 (in PDF or PS) of (1974AJ01). (1977FU09) find that the width of this state varies with E_{p}. ^{8}Be_{g.s.} decays isotropically, as expected from its 0^{+} character (1976KO18). Reaction (b) has been studied for E_{p} = 0.15 to 10.5 MeV. The reaction proceeds predominantly by sequential twobody decay via ^{8}Be*(0, 2.9): see (1974AJ01), ^{12}C in (1975AJ02, 1980AJ01) and (1974KA1J, 1975VA04, 1976GR22, 1977LA13, 1977OH1A). See also (1972TH1C, 1977GR10) and (1978BI1E; applied).
At E(^{3}He) = 25.6 MeV angular distributions have been obtained for the ^{6}Li ions to ^{8}Be*(0, 16.6, 16.9, 17.6). In the range E(^{3}He) = 25.2 to 26.3 MeV, the group to ^{8}Be*(18.2) [J^{π} = 1^{+}; T = 0] is not observed: its intensity is < 0.15 of the intensity to ^{8}Be*(17.6) [J^{π} = 1^{+}; T = 1] (1974DE25). For the earlier work see (1974AJ01), (1972YO02) and ^{6}Li.
Angular distributions have been reported at E_{α} = 28.4 and 29.0 MeV for ^{8}Be_{g.s.} + ^{7}Li_{g.s.}, ^{8}Be_{g.s.} + ^{7}Li*_{0.48} and ^{8}Be*_{2.9} + ^{7}Li (29 MeV only) by (1968KA24) and at 42 MeV for ^{8}Be_{g.s.} + ^{7}Li_{g.s.} and ^{8}Be_{g.s.} + ^{7}Li*_{0.48} by (1968MI05). At E_{α} = 65 MeV ^{8}Be*(16.6 + 16.9, 20.0) are apparently also excited (1973WO06). See also (1974WO1C, 1974WO1D), (1973SC1B) and ^{7}Li.
See ^{12}C in (1975AJ02, 1980AJ01).
This reaction proceeds via ^{8}Be*(0, 2.9) at E_{n} = 13 to 18 MeV and via states in ^{5}He, ^{9}Be and ^{12}C (1966MO05, 1975AN01). See also (1975AN1G, 1976AN16) and ^{12}C in (1975AJ02, 1980AJ01).
Reaction (a) has been studied for 13 < E_{p} < 160 MeV. At low energies it involves ^{8}Be_{g.s.}; at higher energies ^{8}Be*(0, 2.9): see (1974AJ01) and (1969EP01, 1977IO1A, 1977RO02). See also ^{12}C in (1975AJ02, 1980AJ01), (1978CH1G, 1978DE1J) and (1977CH02; theor.). For reaction (b) see (1977CO07; 100 MeV; ^{8}Be(0)) [S_{α} = 0.56 ± 0.12].
Angular distributions have been obtained at E_{d} = 19.5, 28 and 51.8 MeV [see (1974AJ01)] and at E_{d} = 12.7 and 13.2 MeV (1975GO36; ^{8}Be_{g.s.}), 13.6 and 14.6 MeV (1974GA30; ^{8}Be_{g.s.}), at E_{dbar} = 16 MeV (1976JA1G; ^{8}Be_{g.s.}), at E_{d} = 35 MeV (1975BE01; ^{8}Be_{g.s.}) and at 54.3 MeV (1977TA1D: to ^{8}Be*(0, 2.9, 11.4, 16.6 + 16.9)). See also (1973FO1A) and (1974DO03, 1976NA05, 1978TA1F; theor.).
Angular distributions have been measured involving ^{8}Be_{g.s.} + ^{7}Be_{g.s.} and ^{8}Be_{g.s.} + ^{7}Be*(0.43) at E(^{3}He) = 25.5, 27.0 and 29.0 MeV (1976PI10) and at 28 MeV (1970DE12). In addition at E(^{3}He) = 70 MeV the distributions involving ^{8}Be*(2.9, 11.4, 16.6) and ^{7}Be_{0+1}, ^{8}Be*(16.9) and ^{7}Be*(0.43), and ^{8}Be*(17.6) and ^{7}Be*(0, 0.43) have been studied by (1976ST11). See also (1975AU01), (1974DO03; theor.) and ^{7}Be.
This reaction has been studied up to E_{α} = 104 MeV: see (1974AJ01). Angular correlations involving ^{8}Be*(0, 2.9) have been studied at E_{α} = 90 MeV: S_{α}(PWIA) = 2.9 ± 0.4 and 2.8 ± 0.3, respectively; S_{α}(DWIA) for ^{8}Be_{g.s.} = 2.4 ± 0.4 (1976SH02). Angular distributions at E_{α} = 65 MeV (reaction (b)) lead to S_{α} = 0.55 and 0.75 (DWBA) for ^{8}Be*(0, 2.9). ^{8}Be*(11.4) was also observed (1974WO1C, 1976WO11). See also (1977KA1J). See also ^{12}C in (1975AJ02, 1980AJ01), ^{16}O in (1977AJ02), (1973RU09, 1974RU06, 1975CO1C, 1977MC07, 1977YA1A) and (1976ME20; theor.).
At E(^{12}C) ≈ 37 MeV angular distributions (reaction (b)) are reported involving ^{8}Be_{g.s.} + ^{16}O_{g.s.} (1975EB02, 1976EB01). See also ^{16}O in (1977AJ02), ^{24}Mg in (1978EN06), (1974AJ01) and (1974HO30, 1976AR02, 1977WA04). For reaction (a) see (1978FR20) and ^{15}N in (1981AJ01).
See (1974ME09) and ^{20}Ne in (1978AJ03).
Angular distributions have been measured at E_{p} = 45 MeV for the transitions to ^{8}Be*(0, 2.9) (1971BR07). See also ^{6}Li.
See ^{7}Li.
Angular distributions have been obtained at E(^{3}He) = 3.3, 5.0 and 5.8 MeV for the transition to ^{8}Be_{g.s.} + ^{8}Be_{g.s.} (1968JA07). See also ^{12}C in (1975AJ02), ^{16}O in (1977AJ02), (1974BA42) and (1973OG1A).
See (1976TU04, 1977TU1D). See also ^{7}Li.
See (1972FA07).
See (1974AJ01).
See (1974WO1C, 1974WO1D, 1976WO11).
See ^{16}O in (1977AJ02).
See (1974WO1C, 1974WO1D, 1976WO11), (1973SC1B) and ^{12}C in (1980AJ01).
See (1975MI1A).
See (1976AR02), ^{20}Ne in (1978AJ03) and ^{24}Mg in (1978EN06).
