
^{14}N (1981AJ01)(See Energy Level Diagrams for ^{14}N) GENERAL: See also (1976AJ04) and Table 14.10 [Table of Energy Levels] (in PDF or PS). Model calculations: (1976CO1R, 1978FU13). Special states: (1977GO1H, 1977RI08, 1979KI10). Electromagnetic transitions: (1977DO06, 1977KO1N, 1977YO1D, 1978FU13, 1978KI08). Giant resonances: (1979DO17, 1979KI11). Astrophysical questions: (1976AU1B, 1976BO1M, 1976DI1F, 1976DW1A, 1976EP1A, 1976FI1E, 1976GI1C, 1976ME1H, 1976NO1C, 1976OS1E, 1976QU1A, 1976RO1J, 1976SI1D, 1976VA1D, 1976VI1B, 1977AU1B, 1977AU1E, 1977AU1F, 1977AU1J, 1977BE2J, 1977CA1N, 1977CA1J, 1977CA1K, 1977CL1E, 1977CL1C, 1977CO1W, 1977DE1N, 1977HA1L, 1977JO1D, 1977KI1M, 1977LA1G, 1977MA1T, 1977PR1E, 1977ST1J, 1977ST1H, 1977TR1D, 1977WA1P, 1978BO1M, 1978BU1H, 1978BU1B, 1978CL1F, 1978DE1R, 1978DI1D, 1978DW1B, 1978EN1C, 1978GL1E, 1978IB1A, 1978KA1R, 1978LA1K, 1978LU1C, 1978ME1D, 1978OR1A, 1978PO1B, 1978SN1A, 1978ST1C, 1978TO1C, 1978TR1C, 1979GU1D, 1979KA1T, 1979LA1H, 1979NO1F, 1979PE1E, 1979RA1C, 1979SA1M, 1979SW1B, 1979WE1F, 1980CA1C, 1980FR1G, 1980ME1B, 1980PE1F, 1980SP1B). Special reactions involving ^{14}N: (1975KO1F, 1976AB04, 1976BA08, 1976BU16, 1976CH28, 1976EG02, 1976HI05, 1976NA11, 1977AR06, 1977CO14, 1977GE08, 1977GO07, 1977KU1D, 1977NA03, 1977PR05, 1977ST1J, 1977ST1G, 1977TO1G, 1978AB08, 1978BH03, 1978BI03, 1978CR1B, 1978GE1C, 1978GR1F, 1978HE1J, 1978HE1C, 1978KO01, 1979DY01, 1979GA04, 1979GE1A, 1979GO11, 1979HA1Q, 1979HE1D, 1979KO1M, 1979SA27, 1979SA26, 1979SC08, 1979ST1D, 1980MI01). Applied work: (1975SE1J, 1976CH1N, 1976CH1P, 1976EA1A, 1976EC1B, 1976LE1Q, 1976RA1J, 1976SI1G, 1976ST1H, 1976SU1E, 1977LE1J, 1977LO1J, 1977MA1F, 1978MU1E, 1978OX1A, 1978VA1H, 1979AN1L, 1979EN1D, 1979GR1E, 1979VA1D, 1979WI1C, 1979WI1L). Muon and neutrino capture and reactions: (1975BA40, 1975GE1E, 1977BA1P, 1977DO06, 1977GO13, 1977GO1H, 1977MU1A, 1978DE15, 1978GO1Q, 1979DE01, 1979DO1E, 1979GO1M, 1980LO07, 1980MU1B). Pion capture and reactions: (1975BA1W, 1975KA1G, 1975KO25, 1975MA1M, 1976AS1B, 1976BA54, 1976BO2C, 1976EN02, 1976LI26, 1976RO14, 1977DO06, 1977GI14, 1977KO25, 1977MA1M, 1977MA35, 1977MA1F, 1977RI1H, 1977ST09, 1977VI1A, 1977WA1H, 1978BE27, 1978BO25, 1978GI05, 1978KI08, 1978KI13, 1978KW1A, 1978SH12, 1978SH16, 1978WE1H, 1979AMZY, 1979BA16, 1979BA2J, 1979DO17, 1979KI1K, 1979KL07, 1979MA2H, 1979PR1D, 1979SP1C, 1979UL1A, 1980DE10, 1980ER01, 1980FI05, 1980SI07). Kaon capture and scattering: (1977JU1C, 1978AT01, 1978DA1A, 1979RA18). Reactions involving antiprotons: (1977WE1E, 1978PO02). Other topics: (1976CO1R, 1978DA1A, 1978GA1C, 1978KW1A, 1978SO1A, 1979GA1D, 1979HE1F, 1979KA13, 1979KO1V). Ground state of ^{14}N: (1977AN21, 1977GO1H, 1977MA35, 1978AN07, 1978HE1D, 1978ZA1D, 1979BU12, 1979SA27).
Q = +0.0156 b (1978LEZA).
A recent measurement of the (5.83 → 5.11) γray in reaction (b), E_{γ} = 728.34 ± 0.10 keV, leads to E_{x} = 5834.23 ± 0.21 keV (1981KO08) and E.K. Warburton, private communication. See also (1976AJ04).
See (1979CH22).
Observed resonances are displayed in Table 14.13 (in PDF or PS). See also (1976AJ04).
Excitation functions have been measured to E_{α} = 26 MeV. Observed resonances are displayed in Table 14.13 (in PDF or PS). (1975WI04) has expanded the angular distributions of the p_{0} → p_{3} groups into Legendre polynomials and fitted the coefficients at the resonances corresponding to ^{14}N*(13.16, 13.24, 13.67, 13.76) obtaining J^{π} = 1^{+}, 2^{}, 2 or 3^{+}, and 1, respectively, for these states. (1975WI04) also finds that a surprising proportion of states have a higher cross section for neutron than for proton emission: the fluctuations of σ_{n}/σ_{p} at low E_{α} suggest sizable isospin impurities in the ^{14}N states. See also (1970AJ04, 1976AJ04).
Excitation curves have been measured at E_{α} up to 27 MeV [see (1970AJ04, 1976AJ04)] and (1975VA19: E_{α} = 15 to 25 MeV; d_{0}, d_{1}). The low energy resonances are exhibited in Table 14.13 (in PDF or PS). At the higher energies the yield curves are fairly smooth although (1975VA19) show broad resonances in the d_{1} and d_{0} yields corresponding to ^{14}N*(23, 25) respectively, and at θ = 170° (1975SP04) report a sharp rise in the 15.1 MeV γ yield ≈ 1 MeV above the ^{12}C*(15.1) + p + n threshold, a channel which is not isospin forbidden. See also (1976LE1K).
The yield of αparticles [and of 0.7 MeV γrays for E_{α} = 2.1 to 3 MeV] has been measured for E_{α} to 30 MeV [see (1976AJ04)] and for E_{α} = 30 to 50.6 MeV by (1976BE1M; α_{0}). Observed resonances are displayed in Table 14.13 (in PDF or PS). In addition to two strong resonances in the α_{0} yields at E_{α} = 2.21 and 4.26 MeV (^{14}N*(13.19, 14.66)), two other states (^{14}N*(13.72, 14.25)) are required to fit the data: an Rmatrix calculation leads to J^{π} = 3^{+}, 1^{+} [see, however, (1975WI04)], 3^{+} and 2^{} for ^{14}N*(13.19, 13.72, 14.25, 14.66) (1973MO15). A strong resonance at E_{α} = 5.0 ± 0.1 MeV is reported in the reaction cross section for E_{α} = 4.0 to 9.0 MeV (1976GR1F; abstract): it is suggested that J^{π} = 6^{+}.
At E(^{6}Li) = 5 MeV ^{14}N*(0, 3.95, 4.92, 5.11, 5.69, 5.83, 6.20, 6.44, 7.03, 7.97, 8.49, 8.98, 9.12, 9.39, 9.70, 10.10, 10.43 (T = 1, weakly populated), 11.06) are populated ((1966MC05), and private communication). (1975FO01) have examined ^{14}N*(9.13) in detail and conclude that it is a closely spaced doublet of which one member is populated in ^{13}C(p, γ) and has been assigned J^{π} = 2^{}, and the other member, populated here, has J^{π} = 3^{+}. This assignment is based on a DWBA analysis of the angular distributions at E(^{6}Li) = 16.5 and 21.0 MeV which shows the contributions of several L values and, in particular, L = 0. For γ branching ratios see Table 14.12 (in PDF or PS) of (1976AJ04). See also reaction 22.
At E(^{7}Li) = 24 MeV angular distributions of the tritons to ^{14}N*(3.95, 5.83, 6.44, 8.96, 9.13, 10.06, 10.81, 12.79 + 12.83, 13.03, 15.26) have been studied by (1977KO27). ^{14}N*(4.91, 5.11, 5.69, 6.20, 7.03, 7.97, 8.49, 8.98, 9.39, 11.04, 11.05, 11.52, 12.41) are also populated (1977KO27).
The capture γrays [reaction (a)] have been studied at E(^{3}He) = 0.9 to 2.6 MeV (1970BL10; γ_{0}; θ = 0° and 90°). When the barrier penetration factor has been removed a single resonance is observed at E(^{3}He) ≈ 1.4 MeV [^{14}N*(21.8)], Γ_{c.m.} = 0.65 MeV. The higher energy work quoted in (1976AJ04) has not been published. The excitation function for reaction (b) has been measured for E(^{3}He) = 1.5 to 18 MeV [see (1976AJ04)] and 5.0 to 11.5 MeV (1977DA18; n_{0}). A broad peak at E(^{3}He) = 4.15 MeV may indicate the existence of ^{14}N*(24), Γ ≈ 1 MeV (1966DI04). Yield curves for protons [reaction (c)] have been measured for E(^{3}He) = 3.0 to 5.5 MeV (p_{0}, p_{1}, p_{1} + p_{2} + p_{3}): they are rather featureless (1959HO01). This is also true for the ground state deuterons of reaction (d) in the same energy interval (1959HO01). Yield curves for reaction (e) have been measured for E(^{3}He) = 6 to 30 MeV: see (1976AJ04). See also ^{13}C and ^{13}N, and ^{11}B, ^{11}C, ^{12}C in (1980AJ01). The excitation functions for αparticle groups [reaction (g)] have been measured for E(^{3}He) = 0.9 to 5.5 MeV: see (1976AJ04). No significant resonance behavior is seen except for the α_{2} group which, in the 15° excitation function, exhibits a resonance at E(^{3}He) = 4 MeV, Γ ≈ 1 MeV (1965FO06). See also ^{10}B in (1979AJ01). The excitation function for reaction (h) to ^{6}Li_{g.s.} + ^{8}Be_{g.s.} has been measured for E(^{3}He) = 1.4 to 5.8 MeV: no pronounced structure is observed (1967YO02). At E(^{3}He) = 25.20 to 26.25 MeV the excitation functions for the transitions to ^{8}Be*(0, 16.63, 16.91, 17.64) are smooth, indicating a predominantly direct reaction mechanism (1974DE25).
Angular distributions have been measured for E_{α} to 13.9 MeV [see (1970AJ04, 1976AJ04)] and at E_{α} = 2.05 MeV (1977NI03). See also ^{15}N and (1976EP1A, 1980DO1C; astrophys.).
See (1970AJ04).
At E(^{11}B) = 114 MeV the relatively strongly populated states are ^{14}N*(5.83, 8.96, 12.8) [J^{π} = 3^{}, 5^{+}, 4^{+}] (1974AN36).
At E_{d} = 1.5 MeV the capture cross section is < 1μb (1955AL16). [The other work quoted in (1976AJ04) has not been published.]
Resonances in the yields of neutrons and protons are displayed in Table 14.14 (in PDF or PS). Measurements of the yields of neutrons (to E_{d} = 17 MeV) and of protons (to E_{d} = 14.7 MeV) are listed in Tables 14.11 (in PDF or PS) (1970AJ04) and 14.16 (in PDF or PS) (1976AJ04). The yield of n_{0} has also been measured by (1976WA1L: E_{d} = 5.5 to 12.5 MeV). This preliminary work is characterized by a broad bump at E_{d} ≈ 7 MeV and by a somewhat sharper one at E_{d} ≈ 9 MeV (1976WA1L). For angular distributions see ^{13}C, ^{13}N. For spallation measurements see (1978AZ1E, 1978DU1B). The vector analyzing power and the 0° transverse vector polarization transfer coefficient, K^{y'}_{y}(0°) have been measured for E_{dbar} = 5.7 to 9.7 MeV [n_{0}, n_{1}]. The values of K^{y'}_{y} are large, close to the maximum value of 2/3, consistent with a model of the neutron as a simple spectator in the reaction (1976TE03). K^{y'}_{y}(0°) has also been measured for 5 < E_{dbar} < 12 MeV (1976WA1L; prelim.; n_{0}, n_{1}). Other recent measurements are those of the tensor polarization power for E_{dbar} = 9 to 11 MeV (1977DR1F; p; prelim.) and the vector analyzing power at E_{dbar} = 11 MeV (1976KR1B; n_{0}, n_{1}; prelim.). See also (1979SI07). For the earlier polarization measurements of neutrons (to E_{d} = 51.5 MeV) and of protons (to E_{d} = 51 MeV) see the listings in Table 14.12 (in PDF or PS) (1970AJ04) and 14.17 (in PDF or PS) (1976AJ04). See also (1974LO1B, 1977HA1P, 1977SE1C, 1977SE09), (1977YO1F, 1977YO1G; applications) and (1975BO58, 1976SA04, 1978HA1Q, 1979SE04; theor.).
Reported resonances are displayed in Table 14.14 (in PDF or PS). Yield measurements of d_{0} up to E_{d} = 26.5 MeV are listed in Table 14.16 (in PDF or PS) of (1976AJ04). See also (1976BO1Q: E_{d} = 1.6 to 3.0 MeV). For total crosssection measurements at E_{d} = 1.55 and 2.89 GeV/c see (1978JA16). See also (1979DE1P). Polarization measurements to E_{d} = 51 MeV are displayed in Table 14.17 (in PDF or PS) of (1976AJ04). Recent work has been carried out at E_{d} = 12.6 MeV (1976ZA1B; d_{0}; VAP), E_{dbar} = 29.5 MeV (1977PE07; d_{0}; VAP, TAP) and 52 MeV (1980MA10, 1976BE1U; to ^{12}C*(0, 4.4, 9.6)). The (d, np) processes are discussed in reaction 50 of ^{12}C in (1980AJ01), reaction 36 in ^{13}C and reaction 19 in ^{13}N. See also (1976GE20). See also (1975BO58, 1977FR12, 1978HA1Q; theor.).
At E_{dbar} = 29 MeV, polarizations to the ground states of ^{11}B and ^{11}C have been studied by (1978CO13). See also (1976AJ04).
Reported resonances are displayed in Table 14.14 (in PDF or PS). Listings of measurements of the yields of αgroups to E_{dbar} to 29.5 MeV are given in Tables 14.16 (in PDF or PS) (1976AJ04) and 14.11 (in PDF or PS) (1970AJ04). The major interest in this reaction has been the study of the yield of the α_{2} group to the J^{π} = 0^{+}, isospin "forbidden" T = 1 state. In particular, the work of (1972SM07, 1971RI15) has shown that while the α_{0}, α_{1} and α_{3} yields show only weak fluctuations, the α_{2} "forbidden" yield shows narrow resonances which implies that the source of the isospin mixing (at least in the region which they, and the subsequent work of (1974JO01) studied: E_{d} = 7.2 to 16 MeV) is due to states in the ^{14}N compound nucleus. The ratio of the σ_{t} for the α_{2} group compared to the σ_{t} for the "allowed" groups is ≈ 1%, an order of magnitude greater than predicted by direct or multistep processes (1972SM07). Partial wave analyses lead to the resonance parameters shown in Table 14.14 (in PDF or PS) (1972SM07, 1974JO01). See also (1970AJ04). Polarization measurements are reported for the α_{0} → α_{4} groups at E_{dbar} = 11 to 14 MeV (1976PE08) and 20.7 and 29 MeV (1977CO17). See also (1976KU1D), (1974LO1B) and (1977TO1E, 1978IZ02, 1979SE04; theor.).
Vector analyzing power measurements have been carried out at E_{dbar} = 16 MeV for the group to ^{8}Be_{g.s.} (1976JA1G). See also (1976JA1H) and ^{7}Be and ^{8}Be in (1979AJ01).
Angular distributions have been measured at E_{t} = 1.12 to 1.68 MeV (1971MA46: n_{0}, n_{1}, n_{2}) and at 8 MeV (1972CO01: to ^{14}N states with E_{x} < 8.7 MeV).
Observed proton groups are displayed in Table 14.15 (in PDF or PS). Angular distributions have been measured for E(^{3}He) to 25.3 MeV: see (1970AJ04, 1976AJ04). Extensive studies of p'γ and p'p correlations (the latter from ^{12}C(^{3}He, p')^{14}N*(p)^{13}C_{g.s.}) have led to the confirmation and determination of J^{π} of many of the unbound states: see Tables 14.15 (in PDF or PS) and 14.11 (in PDF or PS): see (1970AJ04, 1976AJ04) for a fuller discussion and a listing of the relevant references. Recently (1977HE04: E(^{3}He) = 11 to 20 MeV) have studied p'γ angular correlations involving ^{14}N*(3.95, 5.10, 5.69, 6.21, 7.03). (1978MO27) find g = 0.66 ± 0.04 for ^{14}N*(5.11): τ_{m} for ^{14}N*(5.11, 5.83) are displayed in Table 14.12 (in PDF or PS). See also (1978MO1N). See also ^{15}O, (1966YO1A, 1979HAYZ), (1974LO1B) and (1976EP1A; astrophys.).
Angular distributions of deuterons corresponding to T = 0 states in ^{14}N have been measured at E_{α} = 42 MeV: see Table 14.19 (in PDF or PS) in (1976AJ04), and (1970AJ04) for a listing of the references. At E_{α} = 55 MeV, d_{0} and d_{1} angular distributions have been studied by (1976VA07). The deuteron spectrum is dominated by very strong groups corresponding to the (d_{5/2})^{2}, J^{π} = 5^{+} state at 8.96 MeV, and to a state at 15.1 MeV: see (1976AJ04). See also (1976BU21).
At E(^{6}Li) = 20 MeV, α groups corresponding to most of the T = 0 states with E_{x} < 12.7 MeV are reported: see Table 14.19 (in PDF or PS) in (1976AJ04). The spectrum is dominated by the αgroup corresponding to the 5^{+} state at 9.0 MeV (1968ME10). Angular distributions have also been measured for E(^{6}Li) = 2 to 33 MeV [see (1970AJ04, 1976AJ04)] and at E(^{6}Li) = 10.5 to 13.75 and 20 MeV (1975SO1E, 1978SO01: α_{0}, α_{1}, α_{2}) and E(pol. ^{6}Li) = 20 MeV (1978MA13, 1979MA1T: analyzing power, all known T = 0 states with E_{x} < 10.9 MeV). For the yield of the isospin "forbidden" group, α_{1}, see ^{18}F in (1978AJ03, 1983AJ01). See also (1978AR01) and (1977WE08, 1978ME20; theor.).
See (1976AJ04).
At E(^{11}B) = 114 MeV the spectrum is dominated by groups to the 5^{+} state at E_{x} = 8.96 MeV and to one or more of the states at 12.8 MeV, presumably the 4^{+} one (1974AN36, 1975PO10). See also (1976AJ04).
This reaction has been studied at E(^{12}C) = 114 MeV: the spectrum is dominated by ^{14}N*(8.96)[J^{π} = 5^{+}] but there is substantial population also of ^{14}N*(5.83) [3^{}] and of a state at E_{x} = 11.2 MeV (1974AN36). Angular distributions are reported at E(^{12}C) = 58 to 64.5 MeV (1979CL06) and at 93.8 MeV (1979FU04).
See (1976AJ04).
See (1979MEZX).
Observed resonances are displayed in Table 14.16 (in PDF or PS). The decay schemes of various levels of ^{14}N, as derived from the γspectra in this and other reactions, are exhibited in Table 14.11 (in PDF or PS). For τ_{m} see Table 14.12 (in PDF or PS) and (1977BI07, 1980AN1E). The lowenergy capture cross section yields an extrapolated Sfactor at E_{p} = 25 keV (c.m.), S_{0} = 6.0 ± 0.8 keV · b (1960HE14). See also (1970AJ04). The capture cross section rises from (7.7 ± 1.8) × 10^{10} b at E_{p} = 100 keV to (9.8 ± 1.2) × 10^{9} b at E_{p} = 140 keV (1961HE02). Following is a summary of the reasons for the assignments of J^{π}; T to some of the lower resonances displayed in Table 14.16 (in PDF or PS): for a fuller discussion and complete references see (1970AJ04, 1976AJ04) and see Table 14.11 (in PDF or PS). ^{14}N*(7.97): angular distribution of the γrays is consistent with J^{π} = 2^{}. ^{14}N*(8.06): width of resonance, isotropy of γrays show l_{p} = 0: J^{π} = 1^{} from ^{13}C(p, p); E1 transition to g.s. is uninhibited, e.g., T = 1 [but 1.4% 8.06 → 2.3 transition [E_{x} = 2312.6 ± 0.3 keV] shows T = 0 admixture: α^{2} = 0.046]. The strong transition 8.06 → 5.69 [3.5%] permits either E1 or M1, ΔT = 1. Since 5.69 → 2.31 is seen ^{14}N*(5.69) cannot have J^{π} = 0^{+}, and 2^{+} is excluded by the strength of the 8.62 → 5.69 transition. It is then J^{π} = 1^{}; T = 0 [the isospin mixing α^{2} = 0.09]; E_{x} = 5690.5 ± 1.5 keV. ^{14}N*(8.49, 8.96, 9.12) correspond to anomalies in the cross section. The nature of their γdecays [see Table 14.11 (in PDF or PS)] and the angular distribution leads to J^{π}; T = 4^{}; 0, 5^{+}; 0, 3^{+}; 0, respectively [see (1978KE01) for a recent study of ^{14}N*(9.13)]. ^{14}N*(8.62) [J^{π} = 0^{+} from ^{13}C(p, p)] shows strong transitions to ^{14}N*(0, 3.95, 5.69): T = 1. The strength of the 8.62 → 3.95 decay shows it is dipole and therefore J = 1 for ^{14}N*(3.95) [E_{x} = 3947.6 ± 0.4 keV]. The strength of the transition 8.62 → 6.21 and the angular correlation 8.62 → 6.21 → g.s. is consistent with J^{π} = 1^{+}, T = 0 for ^{14}N*(6.20) [E_{x} = 6203.7 ± 0.6 keV]. ^{14}N*(8.79) [J^{π} = 0^{} from ^{13}C(p, p)] has a large Γ_{γ} consistent with E1 and T = 1. ^{14}N*(9.17): angular correlation and angular distribution measurements indicate J^{π} = 2^{+} for that state, 3^{} for ^{14}N*(6.44) [see, however, Table 14.10 (in PDF or PS)] and J = 2 for ^{14}N*(7.03). The angular distribution of the γrays from 10.23 → 2.31 is consistent with J^{π} = 1^{+} for ^{14}N*(10.23): T = 0 from M^{2}(M1) [see, however, Table 14.10 (in PDF or PS)]. The γ_{0} angular distribution is consistent with J = 2 for ^{14}N*(10.43): the similar decay characteristics of this state and of ^{14}N*(9.17) suggest that they are both J^{π} = 2^{+}, T = 1. Below E_{p} = 5.5 MeV only γ_{0} can be observed in the capture radiation. (1971RI13) have observed a number of resonances in the γ_{0} yield and in the yield of the ground state γrays from ^{13}C*(3.09, 3.68, 3.85): these are shown in Table 14.16 (in PDF or PS) in the range E_{p} = 3.7 to 6.6 MeV [see reaction 25 in (1970AJ04) for the earlier work]. Angular distributions and measurements of Γ_{γ0} lead to the J^{π} values shown. Above E_{p} = 7 MeV the γ_{0} yield shows broad structure and the giant dipole resonance at E_{x} = 22.5 and 23.0 MeV (1971RI13). Measurements by (1975PA18) of the γ_{0} and γ_{1} 90° yields for E_{x} = 23 to 33 MeV find that the T = 2 resonances reported by (1971RI13) at E_{x} = 23.7 and 24.2 MeV do not exist and that there is no evidence for the T = 2 GDR between E_{x} = 25 and 29 MeV (1975PA18). The 90° yields of γrays to T = 0 states (4.9 < E_{x} < 5.9 MeV) and to T = 1 states (8.0 < E_{x} < 9.5 MeV) have been measured from E_{x} = 23 and 26 MeV, respectively, to E_{x} = 33 MeV (1975PA18). A recent study of the 90° yield of γ_{0} and γ_{1} [and of analyzing powers] has been reported for E_{pbar} = 6.25 to 17.0 MeV by (1980TU01). The γ_{0} results are in good agreement with those of (1974BA37) in the inverse reaction [^{14}N(γ, p)^{13}C]. Broad structures are observed at E_{p} ≈ 8, 13, 14, 15 and 16.5 MeV. The γ_{1} results indicate that the T = 0 strength is spread out fairly uniformly between E_{x} = 13 and 23 MeV (1980TU01). At E_{p} = 25 MeV strong transitions are observed to two groups of states centered near E_{x} = 5.8 and 8.9 MeV (1980MA1E). See also (1966YO1A, 1976KR1A, 1979TR1G) and (1975ZI1A, 1976BR1H; astrophys.).
The elastic scattering has been studied for E_{p} = 0.14 MeV to 11 MeV: see (1970AJ04, 1976AJ04). For observed resonances see Table 14.16 (in PDF or PS); for angular distributions see ^{13}C. The yields of p_{0} at eight angles (and the analyzing power) have been measured for E_{pbar} = 9.1 to 18.4 MeV. A phase shift analysis implies the existence of resonances with J^{π} = 1^{}, 2^{} and 3^{+} in the vicinity of E_{p} ≈ 15 MeV. The 1^{} and 2^{} resonances have widths of ≈ 3  4 MeV and have a total Γ_{p}/Γ value of 0.1. The correlation between these resonances and the GDR is not clear. There is no indication of the T = 2 states previously reported in reaction 30 (1978WE13). For other polarization measurements see (1976AJ04) and (1976TR1C). See also (1978DW1A; astrophys.).
The yield of neutrons has been measured from threshold to E_{p} = 13.7 MeV: see (1970AJ04). Observed resonances are displayed in Table 14.17 (in PDF or PS). The ratio of the reaction cross section at E_{p} = 22.8 MeV to the n_{0} yield is 1.06 ± 0.07: thus there is little competition of γrays from excited states of ^{13}N with neutron emission making this a convenient fast neutron calibration source (1975LI11). The 0° polarization transfer coefficients have been measured for E_{pbar} = 7.9 to 14.6 MeV (1976LI08). For other polarization measurements see (1965WA02; n_{0}; E_{p} = 6.9 to 12.3 MeV) and (1979CLZS; 6 MeV). See also (1979BYZZ), (1974LO1B, 1976WA1B, 1979BY1B) and ^{13}N.
Analyzing power measurements for ^{12}C*(0, 12.71, 15.11, 16.11) have been measured at E_{pbar} = 65 MeV (1979HO1H) and those for ^{12}C*(0, 4.4) are reported at E_{pbar} = 200 MeV (1979CA1A). See also (1976AJ04), ^{12}C in (1980AJ01) and (1980MC1C, 1980WH1A).
At E_{p} = 49.6 MeV polarization measurements have been carried out for the tritons and ^{3}He ions to the mirror groups ^{11}B*(0, 2.12, 4.45, 5.02, 6.74, 12.91) and ^{11}C*(0, 2.00, 4.32, 4.80, 6.48, 12.50) (1974MA12). See also (1976AJ04) and ^{11}B, ^{11}C in (1980AJ01).
Excitation functions have been measured from E_{p} = 5.5 (α_{0}), 6.0 (α_{1}), 7.0 (α_{2}), 8.0 (α_{3}), 10 (α_{4}), 11 (α to ^{10}B*(5.11)) to 18 MeV. Total cross sections have also been obtained for the production of ^{6}Li, ^{9}Be and ^{10}B: the latter shows a great deal of structure. The consequences for astrophysical problems are discussed by (1975OB01). The analyzing power for the α_{0} group has been measured at E_{pbar} = 65 MeV by (1980KA03). See also ^{10}B in (1979AJ01).
Observed neutron groups are displayed in Table 14.18 (in PDF or PS). Angular distributions have been reported at many energies up to E_{d} = 12 MeV: see (1970AJ04) and Table 14.18 (in PDF or PS). Comparisons of relative spectroscopic factors obtained in this reaction and in reaction 35 are shown in Table 14.23 (in PDF or PS) of (1976AJ04): it appears that S_{rel} for ^{14}N*(2.31) [T = 1] is smaller in this reaction than in the (^{3}He, d) reaction although simple DWBA calculations would suggest that the factors would be the same in both proton pickup reactions. The τ · T terms appear to be energy dependent: see Table 14.23 (in PDF or PS) (1976AJ04). See also ^{15}N and (1976FOZW).
Angular distributions have been studied at E(^{3}He) = 13 to 17 MeV [see (1976AJ04) and Table 14.18 (in PDF or PS)]. At E(^{3}He) = 13 MeV the angular distributions of deuterons and singlet deuterons to ^{14}N*(0, 2.31, 3.95) have been investigated by (1976JA14): the relative spectroscopic factors for these three states are 1.0, 1.50, 0.43 for deuterons and 1.0, 1.57, 0.41 for singlet deuterons. Spectroscopic factors for these and other states of ^{14}N observed in this reaction and in reaction 34 are displayed in Table 14.23 (in PDF or PS) of (1976AJ04). At E(^{3}He) = 43.6 MeV ^{14}N*(8.91, 9.51) are strongly populated while ^{14}N*(8.49, 9.13, 9.39) are weakly excited. The d_{5/2} transfer to T = 0 states is concentrated in the transitions to ^{14}N*(5.11, 5.83) (1980HA1E). See also (1979MA2K; theor.).
Angular distributions have been measured at E_{α} = 27 MeV for the α groups to ^{14}N*(0, 2.31, 3.95, 4.92, 5.11). See also (1976AJ04), (1976LE1K) and (1978ZE03, 1980ZE05; theor.).
At E(^{7}Li) = 34 MeV, angular distributions have been obtained for the transitions to ^{14}N*(0, 2.31, 3.95) (1973SC26).
See (1976AJ04).
See ^{14}C.
Angular distributions have been obtained for the n_{0}, n_{1} and n_{2} groups in the range E_{p} = 6 to 14 MeV [see (1976AJ04)] and at E_{p} = 2.45 MeV (1977NI03; n_{0}) and 35 MeV (1979DO14; n_{0}, n_{2}). DWBA analysis of the latter results favors the inclusion of an isovector tensor interaction in the transition to ^{14}N_{g.s.} (1979DO14). See also ^{15}N.
At E(^{3}He) = 44.8 MeV, triton groups are observed corresponding to all known levels of ^{14}N with E_{x} < 7.1 MeV. Triton groups were also seen to unresolved states with E_{x} = 8.0 → 9.5 MeV, to ^{14}N*(10.43) and to excited states with E_{x} = 12.49 ± 0.04, 12.83 ± 0.05 and 13.70 ± 0.04 MeV. Angular distributions were obtained for nine of the triton groups and analyzed using a local twobody interaction with an arbitrary spinisospin exchange mixture. Dominant L = 0 transitions are found to ^{14}N*(2.31, 3.95, 13.7), L = 1 to ^{14}N*(5.11), L = 2 to ^{14}N*(0, 7.03, 10.43) and L = 3 to ^{14}N*(5.83) (1969BA06). See also reaction 50.
Angular distributions have been studied at E(^{6}Li) = 62 MeV for the transitions to ^{14}N*(0, 3.95, 6.20, 7.03): the L = 0 transition to ^{14}N*(3.95) carries at least 90% of the GT strength (1976GO25). For reactions (b) and (c) see (1980NA14).
The total absorption over the range E_{γ} = 9 to 31 MeV is dominated by a single peak at 22.5 MeV [estimated σ ≈ 29 mb, Γ ≈ 2  3 MeV] and appreciable strength extending beyond 30 MeV. The cross section cannot be accounted for solely by the (γ, n) and (γ, p_{0}) processes: particle unstable excited states of ^{13}C, ^{13}N are involved (1969BE92). The combined (γ, n) and (γ, pn) cross section begins to rise rapidly above 18 MeV, reaches its maximum value of 15 mb at 23.3 MeV and exhibits structure at about 19, 20.5 and 26 MeV. The main peak (Γ ≈ 3.5 MeV: see (1970AJ04)) at 23.3 MeV appears to be split into two absorption levels (1970BE54, 1975BE60, 1975BE1F, 1976BE1H: monoenergetic photons) and (1980JU02). Maxima reported in other experiments and "breaks" in the (γ, n) activation curve are listed in (1970AJ04). Most of the photon absorption in the giant resonance region forms J^{π} = 2^{} states in ^{14}N which decay by dwave neutron emission to ^{13}N_{g.s.}. Some evidence is found for the existence of J^{π} = 0^{} strength at the peak of the giant resonance. Some evidence exists for a small amount of isospin T = 0 mixing near 22.5 MeV (1980JU02). The (γ, p_{0}) and (γ, p_{2}) cross sections and angular distributions have been measured in the giant resonance region by (1972CA34, 1974BA37). The authors infer that the giant dipole states [(p_{3/2})^{1}(2s1d)] which decay by p_{0} emission to ^{13}C*(3.68) carry ≈ 90% of the E1 strength and do not contribute substantially to the (γ, p_{0}) process which is populated by (p_{1/2})^{1}(2s1d) giant dipole states. Above E_{γ} = 22 MeV dwave emission from 2^{} states appears to dominate the (γ, p_{0}) cross section (1972CA34, 1974BA37). See also reaction 30. For reaction (c) see (1977TA1B); for reaction (d) see (1979WI1A). For spallation reactions see (1970AJ04) and (1976TU05, 1978DI1A). See also (1974BU1A, 1977DA1B) and (1979ME1E, 1980ME12; theor.).
See (1976AJ04) and Table 14.19 (in PDF or PS).
The r.m.s. radius of ^{14}N is 2.54 ± 0.02 fm: see (1976AJ04). Form factors have been determined at E_{e} = 60.7 to 122.0 MeV for ^{14}N*(2.31, 3.95, 4.92, 5.11, 5.69, 5.83): the reduced transition probabilities for these states, in singleparticle units, are, respectively, 0.065 ± 0.020, 1.70 ± 0.14, (1.1 ± 0.5) × 10^{7}, 4.1 ± 1.0, (3.8 ± 2.1) × 10^{8} and 6.1 ± 1.3 (1974EN01). E.K. Warburton (private communication) calculates 8.7 ± 0.9 fsec for the τ_{m} of ^{14}N*(3.95), on the basis of (1974EN01), the branching ratios of Table 14.11 (in PDF or PS), and the δ(E2/M1) of (1967OL02). Inelastic scattering (at θ = 180°) gives evidence for the excitation of states with E_{x} = 8.91 to 16.11 MeV: see Table 14.19 (in PDF or PS). See also Table 14.11 (in PDF or PS). See also (1977FR1M, 1978VO12), (1977RI1H) and (1976BH1B, 1978FU13, 1979DO1P, 1979DO17, 1979KI1K, 1980ER01; theor.). For reaction (b) see (1978DE32).
Angular distributions of elastically and inelastically scattered neutrons are displayed in Table 14.23 (in PDF or PS) of (1970AJ04). See also (1975BE1Y, 1978BE2B). Observed γrays are shown in Table 14.25 (in PDF or PS) of (1976AJ04). See also (1979SO1B; applied).
Angular distributions of elastically and inelastically scattered protons have been studied at a number of energies up to E_{p} = 155 MeV: see Tables 14.23 (in PDF or PS) in (1970AJ04) and 14.26 (in PDF or PS) in (1976AJ04) and (1977SA1B; p_{0}; E_{p} = 5.85 MeV), (1979AO02; p_{0}, p_{1}; 21 MeV; pol.), (1980FO05; p_{0}, p_{1}, p_{2} and see Table 14.20 (in PDF or PS); 29.8, 36.6 and 40.0 MeV), (1980FA07; p_{0}; 35.2 MeV), (1980CO05; p_{0}, p_{1}, p_{2}; 122 MeV) and (1980MO01; p_{0}; 144 MeV). (1980FO05) have analyzed angular distributions to ^{14}N*(2.31) with a microscopic model DWA which included contributions from the knockon exchange amplitude and from central, tensor and spinorbit forces. The first were fairly satisfactory. The extracted strengths of the tensor force were 20  75% larger than estimates based on the onepionexchange potential (1980FO05). See also (1976AJ04). Observed inelastic groups are exhibited in Table 14.20 (in PDF or PS). At E_{p} = 800 MeV, the spectra are dominated by the groups to ^{14}N*(9.17, 10.43) [J^{π} = 2^{+}] (1979MO1E; prelim.). For reaction (b) see (1976AJ04). For reaction (c) see (1970AJ04). See also (1977BA85), (1979RA1C; astrophys.), (1976DO12, 1977GA22, 1978GO1L, 1978MA34, 1979KI10, 1979MA20; theor.) and ^{15}O.
Angular distributions of elastically and inelastically scattered deuterons have been studied for E_{d} = 52 MeV: see Table 14.23 (in PDF or PS) in (1970AJ04), (1976AJ04), (1980KR01; d_{0}; E_{dbar} = 10 MeV), and (1976AO01, 1979AO01; d_{0}, d_{1}, d_{2}; E_{d} = 10.0, 11.7, 14.8, 17.9 MeV). Inelastic groups are displayed in Table 14.20 (in PDF or PS). The deuteron group to the 0^{+}, T = 1 state ^{14}N*(2.31) is isospin forbidden: its cross section is 1  2 orders of magnitude less than that to ^{14}N*(3.95) [J^{π}; T = 1^{+}; 0]. It is summarized for E_{d} = 6 to 20 MeV by (1979AO01) who find that the observed isospin violation is well accounted for by a direct multistep reaction mechanism which assumes that there is isospin mixing in the intermediate channels. See also (1976AJ04), ^{16}O in (1977AJ02, 1982AJ01) and (1977IZ01, 1977IZ1B, 1978MA34; theor.).
See (1976AJ04).
Angular distributions of elastically and inelastically scattered ^{3}He ions have been measured at E(^{3}He) up to 44.6 MeV: see Table 14.23 (in PDF or PS) in (1970AJ04) and (1976AJ04). At E(^{3}He) = 44.6 MeV, twelve ^{3}He groups are reported corresponding to states in ^{14}N: see Table 14.20 (in PDF or PS) (1969BA06). The angular distributions were analyzed using a local twobody interaction with an arbitrary spinisospin exchange mixture. A comparison of the cross sections of the reactions ^{14}N(^{3}He, t)^{14}O_{g.s.}, ^{14}N(^{3}He, ^{3}He')^{14}N*(2.31) and ^{14}C(^{3}He, t)^{14}N(0) [which all correspond to transitions between identical initial and final states] shows that they are roughly equal, as would be expected from charge independence, once detailedbalance, isospin coupling and phasespace corrections have been applied (1969BA06).
Angular distributions of elastically and inelastically scattered αparticles have been measured for E_{α} = 7.6 to 104 MeV: see Table 14.23 (in PDF or PS) in (1970AJ04) and (1976AJ04), (1974CH1T, 1976CH24; α_{1}; E_{α} = 7.6 to 16.9 MeV), (1977EN01; α_{0}; 19.8 to 23.1 MeV) and (1976FE12; α_{0}, α_{2→4}, α_{5+6}, α_{7+8}, α_{9}, α_{10}; 23.7 MeV). Table 14.20 (in PDF or PS) displays the observed αgroups. Generally the intensity of the α_{1} group is weak: see (1976CH24) and ^{18}F in (1978AJ03, 1983AJ01). See also (1976YO02). (1976WO11) find S_{α} = 0.75 for ^{14}N_{g.s.}. See also (1977KN1E), (1976HA1Q, 1977MA2E, 1979KN1F), (1979RA1C; astrophys.) and (1977DM1A; theor.).
Elastic angular distributions have been measured at E(^{6}Li) = 19.5 MeV (1977KU06) and 32 MeV (1971GR44) and at E(^{7}Li) = 36 MeV (1976CO23).
See ^{9}Be in (1974AJ01).
Elastic angular distributions (reaction (a)) have been measured at E(^{10}B) = 100 MeV (1975NA15) and E(^{14}N) = 73.9 and 93.6 MeV (1977MO1A, 1979MO14). The elastic distributions (reaction (b)) have been studied at E(^{14}N) = 41, 77 and 113 MeV (1971LI11). For fusion cross sections see (1977HI01, 1978KO1J, 1978WU1C, 1980OR1C). See also (1978TA1B).
Elastic angular distributions have been measured in the range E(^{14}N) = 21.3 to 155 MeV: see (1976AJ04). More recently studies are reported at E(^{14}N) = 37, 47 and 58.3 MeV (1978CO20), 53 MeV (1976ZE04) and 78.8 MeV (1977MO1A, 1979MO14). At E(^{14}N) = 155 MeV the selective population of certain ^{14}N states is observed and angular distributions are reported for the transitions to ^{14}N*(0, 8.96, 12.7) (1975NA11). For fusion cross section measurements see (1976ST12, 1977SW02, 1979GO09, 1979GO11, 1979KO20, 1980WI09) and (1976AJ04). See also (1978DA1E, 1978HA1F), (1976LE1F, 1978TS04, 1979GO1R, 1979NA1G, 1980TA1B), (1978RO1D; astrophys.) and (1976AM01, 1977BA3E, 1977MA11, 1978AV1A, 1978CU1C, 1978CU1E, 1978CU06, 1978FR1N, 1978HO13, 1978KA14, 1978VA1A, 1979MO1J, 1979NA03, 1980LE11, 1980LO02, 1980VA03; theor.).
The elastic angular distribution (reaction (a)) has been measured at E(^{14}N) = 19.3 MeV (1971VO01). For a fusion study see (1980WI09). For reaction (b) see (1976AJ04).
Elastic angular distributions have been studied for E(^{14}N) = 4.99 to 20.22 MeV (1969JA15). For fusion cross section measurements see (1976ST12, 1976SW02). See also (1976AJ04), (1978RO1D; astrophys.) and (1976RU1B, 1978AV1A, 1979HU1B; theor.).
Elastic angular distributions have been measured for E(^{14}N) = 8.08 to 155 MeV: see (1976AJ04). Recent work is reported at E(^{14}N) = 76.2 MeV (1977MO1A, 1979MO14) and 155 MeV (1977TO02: see also ^{16}O in (1982AJ01)). For fusion cross section measurements see (1976ST12, 1977SW02, 1977VO08). See also (1976AJ04) and (1978AV1A, 1978VA1A; theor.).
The elastic scattering has been studied at E(^{14}N) = 19.5 MeV (1977KU06).
For reactions (a, b, c) see (1977TH1G). For reactions (b, c) see (1971KO11: E(^{14}N) = 65, 84 and 88 MeV). For reaction (c) see (1977EC04: E(^{14}N) = 27, 30 and 33 MeV). For reaction (d) see (1978PE13: E(^{14}N) = 39 MeV). See also (1977SC1G, 1980TA1B) and (1979KA27; theor.).
For reaction (a) see (1978BA26; theor.). For reaction (b) see (1978BU10), (1978HO1C) and (1979SA27; theor.). For reaction (c) see (1978HO1C).
Cross sections (integrated to 35 MeV) have been measured for the transitions to ^{14}N*(2.31, 3.95, 5.11 + 5.83, 7.03) (1976PA22). See also ^{15}N.
Angular distributions have been obtained for the deuterons corresponding to ^{14}N*(0 → 8.06, 8.62, 8.91, 8.96 + 8.98, 9.17 → 10.43, 10.81, 11.05, 11.24 + 11.29, 11.36 → 11.66, 11.75, 11.95, 12.20, 12.50, 12.61, 12.79 + 12.82, 13.17 + 13.24, 13.71 + 13.72) (1969SN04: E_{p} = 39.8 MeV). Spectroscopic factors were extracted by DWBA analysis of the l_{n} = 1 pickup angular distributions (1969SN04). See also (1976AJ04).
Observed states in ^{14}N are displayed in Table 14.28 (in PDF or PS) of (1976AJ04) together with the derived spectroscopic factors.
At E(^{15}N) = 30, 32 and 45 MeV the angular distributions involving ^{14}N*(0, 2.31) have been studied: they are symmetric about 90° for the transition to the T = 1 analog state ^{14}N*(2.31) (1975GA17, 1976GA37).
At E_{π} = 230 MeV, γrays from the decay of ^{14}N*(2.31, 3.95, 5.11, 5.83) are observed (1974LI15).
For reaction (a) see (1979WIZW) and ^{16}O in (1982AJ01). At E_{p} = 75 MeV, angular distributions to ^{14}N*(0, 3.95) have been studied by (1977GR04); ^{14}N*(2.31) is also populated. See also (1976GO1E).
Angular distributions have been measured in the range E_{p} = 27 to 54.1 MeV: see (1976AJ04) and at E_{p} = 27.0 to 30.7 MeV (1978GO04; to ^{14}N*(2.31)). A number of comparisons have been made of the ratio of (p, ^{3}He) to the T = 1 state at 2.31 MeV and of (p, t) to the analog ground state of ^{14}O: see e.g. (1978GO04). See also ^{17}F in (1982AJ01) and (1976DA1K).
Angular distributions have been measured at many energies up to E_{d} = 40 MeV: see Table 14.25 in (in PDF or PS) (1970AJ04), (1976AJ04) and (1973CA30; α_{0}; 0.98 → 1.97 MeV), (1976LU1A; α_{0}, α_{2}; 16 MeV) and (1976VA07: α to ^{14}N*(0, 3.95, 7.03, 11.04; 40 MeV). Analysis with a onestep ZRDWBA is reported by (1976VA07) And S values are derived: ^{14}N*(11.04) probably has J^{π} = 3^{+}. The yield of the isospin forbidden α_{1} group [to ^{14}N*(2.31)] has been studied for E_{d} = 2 to 15 MeV by (1969JO09, 1973JO13): the intensity of the isospin group is strongly dependent on E_{d} and on the angle of observation. The α_{1} reaction appears to proceed almost exclusively by a compound nuclear process and its study leads to the determination of a large number of ^{18}F states: the average isospin impurity in ^{18}F for 10 ≤ E_{x} ≤ 20 MeV is 3  10% (1973JO13). At E_{d} = 50 MeV, the intensity of ^{14}N*(2.31) is 0.1  0.2% that of ^{14}N_{g.s.} (1975FA06). See also ^{18}F in (1978AJ03, 1983AJ01) and (1976PE08, 1978RI05). Measurements on the absolute cross sections of this reaction [E_{d} = 3.6 to 5.3 MeV] and its inverse [ ^{14}N(α, d)^{16}O] are consistent with the principle of detailed balance. An upper limit of 0.2% is assigned to the timereversal noninvariant part of the reaction amplitudes (1971TH03). See also (1978HI1E, 1978PI15; applications).
At E_{α} = 42 MeV the transitions involving (^{14}N_{g.s.} and ^{6}Li*(0, 3.56)), (^{14}N*(2.31) + ^{6}Li_{g.s.}) and (^{14}N*(3.95) + ^{6}Li_{g.s.}) have been studied by (1972RU03).
See (1978BE1G).
See (1976AJ04).
See (1974RO04).
See (1978SE08) and ^{18}F in (1978AJ03, 1983AJ01).
See (1967DE03).
