
^{14}N (1991AJ01)(See Energy Level Diagrams for ^{14}N) GENERAL: See also (1986AJ01), 2 [Electromagnetic Transitions in A = 1315] (in PDF or PS), 14.10 [Table of Energy Levels] (in PDF or PS) and 14.11 [Radiative decays in ^{14}N] (in PDF or PS). Nuclear models:(1985KW02, 1986ZE1A, 1987KI1C, 1988WO04, 1989TA01, 1989WO1E, 1990HA07, 1990VA01) Special states:(1985AD1A, 1985BA75, 1985GO1A, 1986ADZT, 1986AN07, 1986GO29, 1987BA2J, 1987BL15, 1987KI1C, 1987SU1G, 1988KW02, 1988WRZZ, 1989AM01, 1989OR02, 1989SU1E, 1989TA01) Electromagnetic transitions and giant resonances:(1984VA06, 1985GO1A, 1985GO1B, 1986ER1A, 1987BA2J, 1987KI1C, 1988YA10, 1988WRZZ, 1989AM01) Astrophysical questions:(1982CA1A, 1982WO1A, 1985BR1E, 1985DW1A, 1985PR1D, 1986CH1H, 1986DO1L, 1986HA2D, 1986LA1C, 1986MA1E, 1986SM1A, 1986TR1C, 1986WO1A, 1987AL1B, 1987AR1J, 1987AR1C, 1987AU1A, 1987BO1B, 1987CU1A, 1987DW1A, 1987ME1B, 1987MU1B, 1987PR1A, 1987RA1D, 1987WA1L, 1988BA86, 1988CUZX, 1988DU1B, 1988DU1G, 1988EP1A, 1988KR1G, 1988WA1I, 1989AB1J, 1989BO1M, 1989CH1X, 1989CH1Z, 1989DE1J, 1989DU1B, 1989GU1Q, 1989GU28, 1989GU1J, 1989GU1L, 1989HO1F, 1989JI1A, 1989KA1K, 1989KE1D, 1989ME1C, 1989NO1A, 1989PR1D, 1989WY1A, 1990HA07, 1990HO1I, 1990RO1E, 1990SI1A, 1990WE1I) Complex reactions involving ^{14}N:(1984MA1P, 1984XI1B, 1985BE40, 1985KW03, 1985PO11, 1985RO10, 1985SH1G, 1985ST20, 1985ST1B, 1985WA22, 1986AI1A, 1986BO1B, 1986GR1A, 1986GR1B, 1986HA1B, 1986MA13, 1986MA19, 1986ME06, 1986PL02, 1986PO06, 1986SA30, 1986SH2B, 1986SH1F, 1986VA23, 1986WE1C, 1987BA38, 1987BE55, 1987BE58, 1987BO1K, 1987BU07, 1987FE1A, 1987GE1A, 1987GO17, 1987HI05, 1987JA06, 1987KO15, 1987LY04, 1987MU03, 1987NA01, 1987PA01, 1987RI03, 1987RO10, 1987SH23, 1987ST01, 1987TE1D, 1988AY03, 1988CA27, 1988GA12, 1988HA43, 1988KA1L, 1988LY1B, 1988MI28, 1988PAZS, 1988POZZ, 1988PO1F, 1988SA19, 1988SH03, 1988SI01, 1988TE03, 1988UT02, 1989BA92, 1989BR35, 1989CA15, 1989CEZZ, 1989GE11, 1989KI13, 1989MA45, 1989PO06, 1989PO07, 1989PR02, 1989SA10, 1989VO19, 1989YO02, 1989ZHZY, 1990BO04, 1990DE14, 1990GL01, 1990LE08, 1990PA01, 1990WE14, 1990YE02) Applied work:(1985GO27, 1985KO1V, 1986BO1L, 1986CO1Q, 1986HE1F, 1986NO1C, 1986PH1A, 1986ST1K, 1986ZA1A, 1987SI1D, 1987ZA1D, 1988AL1K, 1988GO1M, 1988ILZZ, 1988RO1F, 1988RO1L, 1988ZA1A, 1990KO21) Muon and neutrino capture and reactions:(1985AG1C, 1985KO39, 1986IS02, 1987SU06, 1988AL1H, 1988BU01, 1989MU1G, 1989NA01, 1990CH13, 1990GR1G) Pion capture and reactions:(1983AS01, 1984AS05, 1985BE1C, 1985KO1Y, 1985LA20, 1985RO17, 1985TU1B, 1986AR1F, 1986BE1P, 1986CE04, 1986DY02, 1986ER1A, 1986GE06, 1986KO1G, 1986LAZL, 1986PE05, 1986RA1J, 1986RO03, 1986SU18, 1987AH1A, 1987BL15, 1987BO1D, 1987BO1E, 1987DOZY, 1987GI1B, 1987GI1C, 1987GO05, 1987KA39, 1987KO1O, 1987LE1E, 1987NA04, 1987RO23, 1988GIZU, 1988KO1V, 1988MI1K, 1988OH04, 1988TI06, 1989BA63, 1989CH31, 1989DI1B, 1989DO1L, 1989GA09, 1989GE10, 1989GIZW, 1989GIZV, 1989IT04, 1989KH08, 1989NA01, 1989RI05, 1990BE24, 1990CH12, 1990CH1S, 1990DI1D, 1990ER03, 1990ER1E, 1990GH01) Kaon capture and reactions:(1985BE62, 1986BE42, 1986DA1G, 1986FE1A, 1986MA1C, 1986WU1C, 1989BEXX, 1989BEXU, 1989DO1I, 1989DO1K, 1989SI09) Antinucleon reactions:(1986BA2W, 1986KO1E, 1986RO23, 1986SP01, 1987AH1A, 1987GR20, 1987HA1J, 1987PO05, 1989RI05, 1990JO01) Hypernuclei:(1984BO1H, 1984ZH1B, 1986FE1A, 1986GA1H, 1986MA1C, 1986WU1C, 1986YA1Q, 1988MA1G, 1988MO1L, 1989BA92, 1989BA93, 1989DO1K, 1989IT04, 1989KO37, 1990IT1A) Other topics:(1985AD1A, 1985AN28, 1986ADZT, 1986AN07, 1987BA2J, 1988GU1C, 1988HE1G, 1988KW02, 1989DE1O, 1989OR02, 1989PO1K, 1990MU10, 1990PR1B) Ground state of ^{14}N:(1985AN28, 1985GO1A, 1985ZI05, 1986GL1A, 1986RO03, 1986WI04, 1987AB03, 1987KI1C, 1987VA26, 1988BI1A, 1988VA03, 1988WO04, 1988WRZZ, 1989AM01, 1989AN12, 1989GOZQ, 1989SA10, 1989WO1E, 1990BE24, 1990VA1G, 1990VA01)
Q = +0.0193 (8) b (1980WI22). See also (1986HA49) and (1989RA17), < r^{2} >^{1/2} = 2.560 (11) fm (1980SC18), Natural abundance:(99.634 ± 0.009)% (1984DE53)
The energy of the 5.83 → 5.11 γ transition is E_{γ} = 728.34 ± 0.10 keV. When corrected for the nuclear recoil and added to E_{x} = 5105.89 ± 0.10 keV, E_{x} = 5834.25 ± 0.14 keV for ^{14}N*(5.83) (1981KO08) [recalculated]. For branching ratios see 14.11 (in PDF or PS). See (1981KO08) also for a general discussion of electromagnetic transitions in ^{14}C and ^{14}N, and comparison with theory.
Observed resonances are displayed in 14.12 (in PDF or PS). For thick target yields see (1989HE04). See also (1985CA41; astrophys.).
Excitation functions have been measured to E_{α} = 26 MeV. Observed resonances are displayed in 14.12 (in PDF or PS). (1975WI04) has expanded the angular distributions of the p_{0} → p_{3} groups into Legendre polynominals and fitted the coefficients at 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. However, an Rmatrix analysis by (1983CS03) suggests J^{π} = 2^{}, 3^{+}, 1^{+} for ^{14}N*(13.69, 13.74, 13.77). (1975WI04) 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.
Excitation curves have been measured at E_{α} up to 27 MeV [see (1970AJ04, 1976AJ04, 1981AJ01)]. The low energy resonances are exhibited in 14.12 (in PDF or PS). At the higher energies the yield curves are fairly smooth although broad resonances in the d_{1} and d_{0} yields corresponding to ^{14}N*(23.25), respectively have been reported as has 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 (1981AJ01). For cross sections at E_{α} = 29.5 MeV (reaction (a)) and 25.0 and 30.1 MeV (reaction (b)) see (1983VA28). See also ^{12}C in (1990AJ01) and (1989VA07).
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 50.6 MeV: see (1981AJ01). Observed resonances are displayed in 14.12 (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): see (1981AJ01).
States with E_{x} > 10 MeV studied in this reaction at E(^{6}Li) = 34 MeV are displayed in 14.13 (in PDF or PS) (1984CL08). In addition most of the lowerlying T = 0 states have been populated: see (1970AJ04, 1981AJ01).
At E(^{7}Li) = 24 MeV angular distributions of the tritons to ^{14}N*(3.95, 5.83, 6.45, 8.96, 9.13, 10.06, 10.81, 12.79 + 12.81, 13.03, 15.26) have been studied. ^{14}N*(4.91, 5.11, 5.69, 6.20, 7.03, 7.97, 8.49, 8.98, 9.39, 11.05, 11.51, 12.42) are also populated: see (1981AJ01).
For cross sections see (1986CU02).
The capture γrays [reaction (a)] have been studied at E(^{3}He) = 0.9 to 2.6 MeV (θ = 0°, 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 excitation function for reaction (b) has been measured for E(^{3}He) = 1.5 to 18 MeV [see (1981AJ01)]. A broad peak at E(^{3}He) = 4.15 MeV may indicate the existence of ^{14}N*(24), Γ ≈ 1 MeV. 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. This is also true for the groundstate deuterons of reaction (d) in the same energy interval. Yield curves for reaction (e) have been measured for E(^{3}He) = 6 to 30 MeV: see (1976AJ04). A_{y} measurements for t_{0} and t_{1} are reported at E(pol. ^{3}He) = 33 MeV: see (1986AJ01). See also ^{13}C and ^{13}N, and ^{11}B, ^{11}C, ^{12}C in (1990AJ01). 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. See also ^{10}B in (1988AJ01). 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. 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: see (1976AJ04).
For angular distributions to E_{α} = 13.9 MeV see (1981AJ01). At E_{α} = 47.4 MeV, θ = 0°, unresolved groups are reported to E_{x} = 5.2, 8.6, 14.71, 16.84, 19.10, 20.52, 21.72, 22.38, 23.57 and 24.25 MeV (1988LU02). [See for comments about dominant J^{π}: highspin states are expected to be preferentially populated.] Uncertainties in E_{x} are ± 0.35 MeV for 15 MeV neutrons to 1.5 MeV for 30 MeV neutrons. Widths could not be determined. A state at ≈ 25 MeV was also populated [J.D. Brown, private communication]. See also ^{15}N, (1986AJ01) and (1988CA26; astrophys.).
States with E_{x} > 10 MeV studied in this reaction at E(^{6}Li) = 34 MeV are displayed in 14.13 (in PDF or PS) (1984CL08).
At E_{d} = 1.5 MeV the capture cross section is < 1 μb: see (1970AJ04). See also (1984NA1F). See also (1990HA46).
Resonances in the yields of neutrons and protons are displayed in 14.14 (in PDF or PS). The 0° yield of neutrons shows broad structures at E_{d} ≈ 7.2 and 11.5 MeV [ n_{0}] and 8 and (10.8) MeV [n_{1}] as well as a sharper structure at E_{d} ≈ 9.5 MeV: see (1986AJ01). Polarization measurements for both reactions (a) and (b) have been made at many energies. For the earlier work see (1970AJ04, 1976AJ04, 1981AJ01, 1986AJ01). Recent studies have been reported for reaction (b) at E_{d} = 0.25 → 1.10 MeV (1986KO08; p_{0}) and at E_{pol. d} = 12 MeV (1988LA03; ^{13}C states with E_{x} < 7.7 MeV; VAP, TAP), 56 MeV (1986SA2G; p_{0}, p_{1}; K^{y}_{y'} and K^{y'}_{yy}; prelim.), 2.1 GeV (1987PE19, 1989PU01; TAP; deuteron breakup), and 9.1 GeV/c (1988AB13; TAP). For the breakup at high energies see also (1984KO42, 1989AV02, 1989BE2K). For reaction (c) to ^{12}B*(0, 4.4[u]) at E_{pol. d} = 70 MeV see (1986MO27, 1988MO11; VAP, TAP) [see (1986MO27) for comment re lower energy measurement at 0°]. For a study of the Δregion at E_{pol. d} = 2 GeV see (1989EL05). For a study of the (pol. d, pol. pX) reaction at E_{pol. d} = 65 MeV see (1989IE01). For a report on highenergy γray production see (1989NI1D). For pion production see (1986AJ01) and (1987AG1A). For total cross sections see (1986AJ01) and (1987KI1J; prelim.; 2.0 to 4.0 GeV/c). See also (1984NA1F, 1989NA1R) and (1986AI04; applied).
Reported resonances are displayed in 14.14 (in PDF or PS). For a listing of excitation function measurements see (1976AJ04). A recent study is reported by (1986HO26; E_{d} = 0.60 to 1.10 MeV; d_{0}). For the earlier polarization measurements see (1976AJ04, 1981AJ01, 1986AJ01). A_{y} = 0.412 ± 0.011 at E_{pol. d} = 56 MeV (θ = 47.5°), and VAP and TAP have been studied for E_{pol. d} = 35 to 70 MeV (1985KA1A, 1986KA1Z). Studies of VAP and TAP have also been carried out at E_{pol. d} = 56 MeV (1986MA32; d_{0}) and 191 and 395 MeV (1986GA18; inclusive scattering; on C). At E_{pol. d} = 400 MeV, VAP and TAP measurements are reported for the groups to ^{12}C*(4.4, 9.7, 12.7, 18.3) (1987AR1H; prelim.). For the (d, pn) reaction at E_{pol. d} = 56 MeV see (1989OK02). See also (1987CA14), (1986CL1C, 1990BO11; applied), (1986YA1R) and (1989GOZN; theor.).
At E_{pol. d} = 89.1 MeV A_{y} measurements are reported for ^{11}C*(0, 2.3) (1989SA13). For the earlier work see (1986AJ01).
Reported resonances are displayed in 14.14 (in PDF or PS). 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 (1971RI15, 1972SM07) 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 α_{t} for the "allowed" groups is ≈ 1%, an order of magnitude greater than predicted by direct or multistep processes (1972SM07). An Smatrix analysis leads to the resonance parameters shown in 14.14 (in PDF or PS) (1981JO02). For polarization measurements see (1986AJ01).
Polarization measurements have been reported at E_{pol. d} = 18 and 22 MeV (1987TA07; VAP, TAP; g.s.) and 51.7 MeV (1986YA12; VAP; ^{8}Be*(0, 2.9, 11.4)). See also (1981AJ01).
Angular distributions have been measured to states below 8.7 MeV at E_{t} = 1.12 to 1.68 MeV and at 8 MeV: see (1976AJ04).
Observed proton groups are displayed in 14.15 (in PDF or PS). Angular distributions have been measured for E(^{3}He) to 25.3 MeV [see (1970AJ04, 1976AJ04)] and at E(pol. ^{3}He) = 33 MeV: see (1986AJ01). For a discussion of ^{14}N*(9.13) see (1986WA13). For work at very high energies see (1987AB1J). See also (1986SC35, 1990TO10; applied).
Angular distributions of deuterons have been studied corresponding to the T = 0 states ^{14}N*(0, 3.95, 4.92, 5.11, 5.69, 5.83, 7.97, 8.49, 8.96, 9.13, 9.39, 10.81) [E_{α} = 34.5, 42, 55 MeV; not all states at all energies]. At the higher energies 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 ± 0.1 MeV: see 14.19 (in PDF or PS) in (1976AJ04), and (1981AJ01, 1986AJ01). At E_{α} = 50 MeV the angular distributions of the singlet deuterons exciting the T = 1 states ^{14}N*(2.31, 8.91[u]) have been studied by (1986SA06): a state at 12.6 ± 0.3 MeV is also populated. See also (1989GA1H, 1989SH1G).
At E(^{6}Li) = 20 MeV [see 14.19 (in PDF or PS) in (1976AJ04)] and 32 MeV [see 14.13 (in PDF or PS) here] many of the αgroups corresponding to T = 0 states with E_{x} < 17.2 MeV are observed. The 5^{+} state, ^{14}N*(9.0), is strongly populated: see (1970AJ04). Angular distributions have been measured at E(^{6}Li) = 2 to 33 MeV: see (1981AJ01, 1986AJ01). Inclusive αparticle spectra have been studied at E(^{6}Li) = 156 MeV (1989JE01). See also ^{18}F in (1987AJ02), (1987PA12) and (1986HA1E; theor.).
See (1988GO1H).
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. Angular distributions are reported at E(^{12}C) = 49.0 to 93.8 MeV: see (1981AJ01, 1986AJ01).
At E(^{13}C) = 390 MeV angular distributions have been studied to ^{14}N*(0, 2.31, 5.8[u]) and to unresolved structures and continua. The spectra are dominated by the group to ^{14}N*(5.8) (1987AD07, 1988VO08). See also (1989VO1D).
Observed resonances are displayed in 14.16 (in PDF or PS). The radiative decay is exhibited in 14.11 (in PDF or PS). The lowenergy capture cross section yields an extrapolated Sfactor at E_{p} = 25 keV (c.m.), S_{0} = 6.0 ± 0.8 keV · b. 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: see (1970AJ04). Following is a summary of the reasons for the assignments of J^{π}; T to some of the lower resonances displayed in 14.16 (in PDF or PS): for a fuller discussion and complete references see (1970AJ04, 1976AJ04, 1981AJ01). ^{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; therefore, T = 1 [but 1.4% 8.06 → 2.31 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} = 5691.55 ± 0.13 keV (1981BI17). ^{14}N*(8.49, 8.96, 9.13) correspond to anamolies in the cross section. The nature of their γdecays [see 14.11 (in PDF or PS)] and the angular distribution leads to J^{π} = 4^{}, 5^{+}, 3^{+} [all T = 0], respectively. ^{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 → 6.20 and the angular correlation 8.62 → 6.20 → g.s. is consistent with J^{π} = 1^{+}, T = 0 for ^{14}N*(6.20) [E_{x} = 6203.7 ± 0.6 keV]. ^{14}N*(8.78) [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*(6.45) [see however 14.10 (in PDF or PS)] and J = 2 for ^{14}N*(7.03). For recent studies of ^{14}N*(9.17) see (1981BI17, 1986WA13): E_{x} = 9172.5 ± 0.3 keV from E_{γ}, Γ_{γ0}/Γ_{γ} = (79 ± 4)%, Γ [from (p, p)] = 135 ± 8 eV [135 ± 11 eV in (γ, γ)]. Other E_{x} determined by (1981BI17) are 2312.90 ± 0.03, 3948.2 ± 0.2, 5105.9 ± 0.3, and 6446.3 ± 0.2 keV. See also 14.11 (in PDF or PS) and 14.15 (in PDF or PS). 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, 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. A number of resonances in the γ_{0} yield and in the yield of the groundstate γrays from ^{13}C*(3.09, 3.68, 3.85) have been observed: these are shown in 14.16 (in PDF or PS) in the range E_{p} = 3.7 to 6.6 MeV. 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. Measurements of the γ_{0} and γ_{1} 90° yields for E_{x} = 23 to 33 MeV find that the T = 2 resonances reported earlier 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. 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. A study of the 90° yield of γ_{0} and γ_{1} [and of analyzing powers] has been reported for E_{pol. p} = 6.25 to 17.0 MeV. The γ_{0} results are in good agreement with those 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. At E_{p} = 25 MeV strong transitions are observed to two groups of states centered near E_{x} = 5.8 and 8.9 MeV. For searches for shortlived neutral particles in the decay of ^{14}N*(9.17) see (1986SA2E, 1988SA2A). See also (1985AB15), (1986RO18, 1988KI1C; applied), (1985CA41, 1987WE1C, 1988CA26, 1989BA2P, 1990MA1P; astrophysics) and (1986WE1D, 1987MC1C) and (1980HA30; theor.).
The elastic scattering has been studied for E_{p} = 0.14 MeV to 1 GeV: see (1981AJ01) and ^{13}C here. For observed resonances see 14.16 (in PDF or PS). A_{y} measurements have been reported at E_{pol. p} = 200 and 547 MeV [see (1986AJ01)], at 35 MeV (1986OH03; p_{0→3}), at 71.8 MeV (1989VO05, 1990VO02; p_{0}; and measurements of depolarization parameter, D), at 119 MeV (1988CO05; p_{0} → p_{4} and p to ^{13}C*(7.55, 8.86, 9.5, 9.9)) and at 500 MeV (1990HO06; p_{0}; A_{y} and rotation parameters). See (1990HO1L; prelim.) for measurements at E_{p} = 497.5 MeV on pol. ^{13}C. The 0^{+}  0^{} doublet at E_{x} ≈ 8.7 MeV has been studied by (1984AD04, 1986AD01, 1986SW1A, 1987ZEZZ, 1988ZE1B). For pion production see (1988HU06). See also (1985BL22, 1986ADZT) and (1986RA05, 1987BE1M, 1987BE1P, 1988RA08, 1989AM05, 1989BEXT, 1989GO14, 1989KU07, 1989KU14, 1989KU32, 1989RA1O, 1990DU01; theor.).
Observed resonances are displayed in 14.17 (in PDF or PS). Polarization measurements are reported at E_{pol. p} = 35 MeV (1986OH03; A_{y}; n_{0}, n_{1}, n_{2+3}) and 160 MeV (1984TA07, 1987RA15; A_{y}; D_{NN}(0°); n_{0}, n_{2+3}, and n to ^{13}N*(15.1)[u]). Forwardangle cross sections have been measured at E_{p} = 318 and 800 MeV (1986KI12) and at 492 and 590 MeV (1989RA09). Cross sections for ^{13}N production have been studied for E_{p} = 5.2 to 30.6 MeV by (1989WA16. For the earlier work see (1986AJ01). See also ^{13}N, (1987ALZW, 1990TA1J), (1986AI04, 1989AR1Q; applied), (1985CA41; astrophysics), (1986AL18, 1986CA1N, 1986TA1E, 1987TA22) and (1987BE1D, 1989AM02, 1989RA15; theor.).
A_{y} measurements have been reported at E_{pol. p} = 13.6 to 530 MeV [see (1986AJ01)] and at 119 MeV (1987LE24; to ^{12}C*(0, 4.4, 7.7, 9.6, 12.7, 14.1, 15.1, 16.1, 16.6, 17.8, 18.1, 18.8, 19.9, 20.3, 20.6)). For a measurement of the tensor polarization of ^{12}C*(15.1) at E_{p} = 41.3 MeV see (1987CA20). For other work see (1976AJ04, 1981AJ01) and ^{12}C in (1990AJ01). See also (1986KO1K; theor.).
See ^{11}B, ^{11}C in (1990AJ01), and (1986AJ01).
See (1981AJ01).
Observed neutron groups are displayed in 14.18 (in PDF or PS). See (1970AJ04, 1976AJ04) for comments.
Angular distributions have been reported at E(pol. ^{3}He) = 33 MeV to ^{14}N*(0, 2.31, 3.95, 5.11, 5.83, 8.91, 9.51) (1986DR03; also A_{y}). See 14.18 (in PDF or PS) here, and (1981AJ01), for the earlier work.
See (1981AJ01).
At E(^{7}Li) = 34 MeV angular distributions have been studied to ^{14}N*(0, 2.31, 3.95, 5.0[u], 5.7[u]). ^{14}N*(7.0, 8.9, 9.5) are also populated. ^{14}N_{g.s.} is dominant (1987CO16). See also (1986AJ01), (1988AL1G) and reaction 18 in ^{14}C.
See ^{14}C. See also (1989AM01; theor.).
Forwardangle differential cross sections for the isobaricanalog state (IAS) [^{14}N*(2.31)] have been measured at E_{π+} = 20 MeV (1987IR01), 35 to 80 MeV (1986UL01), 100 to 295 MeV (1983IR04) and 300 to 550 MeV (1988RO03). Angular distributions to the IAS are reported by (1986UL01, 1987IR01), See also (1985IR02, 1989LE1L) and (1989ST1H theor.).
Angular distributions, generally for the n_{0}, n_{1} and n_{2} groups, have been measured in the range E_{p} = 2.45 to 45 MeV [see (1981AJ01, 1986AJ01)] and at E_{pol. p} = 35 MeV (1990IE01) and 160 MeV (1987RA15). (1984TA07) have been measured the transverse spintransfer coefficients [D_{NN}(0°)] at 160 MeV for the groups to ^{14}N*(0, 2.31 [D_{NN} = 1], 3.95, 13.72). The main GT strength lies in the three 1^{+} states and their D_{NN} values, which are consistent with 1/3, are those expected for pure L = 0 transitions (1984TA07). At E_{p} = 60 to 200 MeV the spectra are dominated by the neutrons to ^{14}N*(3.95) (1987TA13). 0° differential cross sections have recently been obtained at E_{p} = 60 to 200 MeV (1987TA13; n_{0}, n_{1}, n_{2}), 200, 300, and 450 MeV (1989AL04; n_{1}, n_{2}) and 492 MeV (1989RA09). See also (1989MAZP). For discussions of the Fermi and GamowTeller strengths see (1985WA24, 1987RA15, 1987TA13, 1989RA09). See also ^{15}N, (1985TA23, 1989SU1J), (1988CA26, 1989KEZZ; astrophysics), (1986AL18, 1986TA1E, 1986VO1G, 1987BE25, 1987GO1V, 1987HE22, 1987RA32, 1988RO17, 1988WA1Q, 1989RA1G, 1989SU1A) and (1986PE1E, 1987LO13, 1987LO1D, 1989AM01; theor.).
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 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). Angular distributions have also been studied at E(^{3}He) = 72 MeV (1988DE34, 1988DE47, 1989ER05; t_{0}, t_{1}, t_{2}).
Angular distributions have been studied at E(^{6}Li) = 34 and 62 MeV [see (1986AJ01)], at 93 MeV (1986BR33, 1987DE02, 1988DE47, 1989DE34; to ^{14}N*(0, 3.95)) and at 84, 150 and 210 MeV (1987WI09, 1986AN29, 1988AN06; to ^{14}N*(0, 2.31, 3.95)). ^{14}N*(3.95) dominates the spectra: see e.g. (1987WI09). ^{14}N*(5.11, 5.83, 6.20, 7.03, 8.49) are also populated (1980WH03, 1987WI09). For studies of the GT strength see (1980WH03, 1987WI09). See also (1987AU04, 1988AU1E, 1988GA1N, 1989AU1B) and (1986AJ01).
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: particleunstable excited states of ^{13}C, ^{13}N are involved. 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: see (1981AJ01). 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 and for a small amount of isospin T = 0 mixing near 22.5 MeV: see (1981AJ01). The cross section for the (γ, n) reaction has recently been measured from threshold to 15.5 MeV (1987FA14). See also (1988DI02). The (γ, p_{0}) and (γ, p_{2}) cross sections and angular distributions have been measured in the giant resonance region. The giant dipole states [(p_{3/2})^{1} (2s1d)] which decay by p_{0} emission to ^{13}C*(3.68) appear to carry ≈ 90% of the E1 strength and do not contibute 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: see (1976AJ04). For reaction (c) see (1987IM02). For rection (d) see ^{14}C. See also (1985FU1C) and (1985GO1A, 1986WI10, 1987HU01, 1987KI1C, 1987LU1B, 1988DU04; theor.).
A measurement of the protons from the ^{14}N(γ, p)^{13}C reaction and a resonant absorption measurement lead to Γ_{γ0}/Γ = 0.052 ± 0.004 for ^{14}N*(9.17) and to Γ = 122 ± 8 eV (1989VA21). See also (1986AJ01), 14.19 (in PDF or PS), (1985BEZI, 1987BE1K) and (1986DU03; theor.).
Form factors have been determined at many energies in the range E_{e} = 60.7 to 300 MeV: see (1981AJ01, 1986AJ01) for the earlier references. In recent work at E_{e} = 80.0 to 372.6 MeV the form factors for ^{14}N*(0, 2.31) have been determined [q = 0.80 to 3.55 fm^{}1] (1987HU01; see for a discussion of the wave functions for these two states): see also (1989AM01, 1989TA01). A number of other excited states of ^{14}N have also been studied: see 14.19 (in PDF or PS). (1984BE13) have populated ^{14}N*(12.50, 13.17, 13.71, 15.43, 15.7, 17.2, 17.8) but not the 5^{} states at E_{x} = 14.66 and 17.46 MeV which are thus presumably T = 0. (1984BE13) report that within the triplet of 5^{} states at 14.66, 16.91, 17.46 MeV, they can account for ≈ 60% of the isovector 5^{} strength but only 35% of the isoscalar strength. There is no other significant M4 strength up to E_{x} ≈ 28 MeV (1984BE13). See also (1986LI1C, 1987DE43, 1987LI30, 1987RO23) and (1985CH1F, 1985CH1G, 1985GOZP, 1986DO11, 1986ER1A, 1986GO29, 1986JE1B, 1986ZE1A, 1987GO08, 1988AL1J, 1988GO1R, 1988YA10, 1990BE24, 1990GA1M; theor.).
Angular distributions at E_{π±} = 162 MeV have been studied to the states listed in 14.20 (in PDF or PS) (1983GE03). See also the "GENERAL" section.
Angular distributions of elastically and inelastically scattered neutrons are displayed in 14.23 (in PDF or PS) of (1970AJ04). Recent work is reported at E_{n} = 7.68 to 13.50 MeV (1986CH2F; prelim.; to ^{14}N*(0, 2.31, 3.95, 4.91, 5.11, 5.69, 5.83)), 11, 14 and 17 MeV (1985TE01; n_{0}; prelim.), 20 and 25 MeV (1985PE10; n_{0}) and at 21.6 MeV (1990OL01; n to ^{14}N*(0, 5.83, 7.03) as well as at E_{pol. n} = 10, 12, 14 and 17 MeV (1986LI1M; n_{0}; prelim.). See also (1976AJ04), (1986GEZX, 1989LI26) and (1989STZW; applied).
Angular distributions of elastically and inelastically scattered protons have been studied at many energies up to E_{p} = 800 MeV [see (1981AJ01, 1986AJ01)], at E_{pol. p} = 35 MeV (1990IE01; p_{1}) and 800 MeV (1985BL22; elastic) and at E_{p} = 1 GeV (1985AL16; elastic). For a display of the observed ^{14}N states see 14.24 (in PDF or PS) in (1986AJ01). For a study of the 1.6 and 2.3 MeV γrays [from ^{14}N*(2.31, 3.95)] see (1988LE08). For reaction (b) see (1989BE1P) and ^{13}C. For reaction (c) see (1985DE17). For reaction (d) see ^{10}B (1988AJ01). See also (1989BEXX), (1985PE10, 1987VD1A) and (1986AO1A, 1986ER1A, 1987HU01, 1987VD03, 1988VD1B, 1989AM01, 1989LO1E; theor.).
Angular distributions of elastically and inelastically scattered deuterons have been studied to E_{d} = 52 MeV: see 14.20 (in PDF or PS) in (1981AJ01). 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]: see (1981AJ01). See also (1986HA1E, 1986AO1A; theor.).
Angular distributions of elastically and inelastically scattered ^{3}He ions have been measured at E(^{3}He) up to 44.6 MeV: see 14.20 (in PDF or PS) in (1981AJ01). See also (1989DE1Q).
Angular distributions of elastically and inelastically scattered αparticles have been studied for E_{α} = 7.6 to 104 MeV [see 14.24 (in PDF or PS) in (1986AJ01)] and at E_{α} = 48.7 and 54.1 MeV (1987AB03; α_{0}). See also ^{18}F in (1987AJ02), (1987BU27, 1989BE1R), (1989GU28; astrophysics), (1988PA1K; applied) and (1985SH1D; theor.).
Elastic angular distributions have been measured at E(^{6}Li) = 19.5, 32 and 36 MeV and at E(^{7}Li) = 36 MeV: see (1981AJ01, 1986AJ01). For reaction (b) see also (1986GO1H; E(^{14}N) = 150 MeV; prelim.). See also (1989DE1Q).
See (1986AJ01) and (1988HAZS).
Elastic angular distributions have been measured for reaction (a) at E(^{10}B) = 100 MeV and E(^{14}N) = 73.9 to 93.6 MeV [see (1981AJ01, 1986AJ01)] as well as at E(^{14}N) = 38.1, 42.0, 46.0 and 50.0 MeV (1988TA13); those for reaction (b) have been studied at E(^{14}N) = 41, 77 and 113 MeV: see (1981AJ01). For fusion and other yield measurements see (1986AJ01). See also (1985BE1A, 1985CU1A) and (1985KO1J, 1986RO12; theor.).
Elastic and inelastic angular distributions have been studied in the range E(^{14}N) = 21.3 to 155 MeV [see (1981AJ01)] and at 86 MeV (1988AR23). For cross sections and fusion, fragmentation and evaporation residue studies see (1981AJ01, 1986AJ01) and (1986MO13, 1987GO01, 1987ST01, 1989KI13, 1990WE14). For highenergy γemission see (1986ST07). For neutron emission see (1988KI06). For pion emission see (1989SUZS). For reaction (b) see (1987AR25). See also (1986GO1H, 1987VE1D, 1988HAZS, 1989AR1M), (1982BA1D, 1985BA1T; astrophys.), (1985BE1A, 1985CU1A, 1987GE1B) and (1985HU04, 1985KO1J, 1985VI09, 1986BA62, 1986HA13, 1986POZW, 1986RE14, 1987BI20, 1987RE03, 1987RE11, 1988BA37, 1988HE12, 1988PR02, 1989BL1D, 1989NI1C, 1989RO22, 1989SH05, 1990CA1S, 1990DE13, 1990GH1F, 1990PR01; theor.).
Elastic angular distributions have been measured at E(^{14}N) = 19.3 to 35 MeV and E(^{13}C) = 105 MeV: see (1981AJ01, 1986AJ01) [see also for fusion studies].
Elastic angular distributions have been studied for E(^{14}N) = 5.0 to 20.2 MeV: see (1981AJ01). For fusion and other cross section measurements, see (1981AJ01, 1986AJ01). See also (1985BE1A, 1985CU1A, 1986ST1J, 1986ST1A, 1988BO46) and (1985KO1J, 1986RO12; theor.).
Elastic angular distributions have been studied for E(^{14}N) = 8.1 to 155 MeV [reaction (a)]: see (1981AJ01). For fusion cross section measurements, see (1981AJ01, 1986AJ01). See also (1985BE1A, 1985CU1A) and (1985HU04, 1985KO1J; theor.). For reaction (b), see (1989HO1H; theor.).
Elastic angular distributions have been measured at E(^{14}N) ≈ 53 MeV for reactions (a), (c) and (d) [see (1986AJ01)] and at 84 MeV (1988YA06; reaction (d); also inelastic to ^{28}Si*(1.78)). For fusion and fragmentation studies see (1986AJ01) and (1986SH25, 1987BE55, 1987GU1M, 1987ST01, 1987YI1A, 1988SH03, 1989BR1K, 1990GOZZ). For reaction (e), see also (1988GO12). For pion production [reaction (c)], see (1986ST03). See also (1987SH1A), (1987BL1D) and (1985BL17, 1985CE11, 1985ST20, 1986OS05, 1986POZW, 1986PR01, 1988AY03, 1989BH03, 1989CH1K; theor.).
^{14}O_{g.s.} decays predominantly to its analog state ^{14}N*(2.31): E_{x} = 2312.798 ± 0.011 keV (1982WA16): see reaction 1 in ^{14}O. See also (1989AM01; theor.).
See (1988MC01) in ^{15}N. See also (1981AJ01) and (1988GOZM; theor.).
Angular distributions have been obtained at E_{p} = 39.8 MeV for the deuterons corresponding to ^{14}N*(0 → 8.06, 8.62, 8.91, 8.96 + 8.98, 9.17, 9.39, 9.51, 9.70, 10.10, 10.21, 10.43, 11.06, 11.23 + 11.30, 11.39, 11.51, 11.66, 11.74 + 11.80, 11.97, 12.21 + 12.29, 12.52, 12.61, 12.80 + 12.83, 13.17 + 13.23, 13.72). Spectroscopic factors were extracted by DWBA analysis of the l_{n} = 1 pickup angular distributions: see (1969SN04). See also (1970AJ04).
At E_{pol. d} = 89.1 MeV (1989SA13) have investigated the level structure of ^{14}N up to E_{x} = 24 MeV: see 14.21 (in PDF or PS). Above E_{x} = 18.6 MeV no discrete states appear. The observed summed spectroscopic strength is 88% of the shellmodel sum rule. No significant l = 3 strength was seen (1989SA13).
Observed states in ^{14}N are displayed in 14.28 (in PDF or PS) of (1976AJ04) together with the derived spectroscopic factors. Recently, angular distributions and A_{y} have been determined at E(^{3}He) = 33 MeV to ^{14}N*(0, 2.31, 3.95, 5.11, 5.83, 7.03, 9.17, 10.43, 12.5, 13.7) (1986DR03).
See (1981AJ01).
At E_{π+} = 116 MeV proton angular correlations, energy sharing and recoil momentum distributions have been studied to groups corresponding to ^{14}N*(0, 3.9[u], 7.0[u], 11.0[u]). No evidence is seen for other narrow states. The upper limit for the excitiation of ^{14}N*(2.31) [0^{+}; T = 1] is 5% (1988SC14). See also (1990SC1O) and (1989CH04; theor.). Work at E_{π+} = 165 MeV suggests that the earlier work reports too low a cross section and underestimates the twonucleon absorption mechanism (1990HY01). In this paper the fraction of the total absorption cross section which can be attributed to that mechanism is reported to be about 50% (1990HY01). See also (1988KY1A, 1988RO1M).
Angular distributions (reaction (a)) have been measured in the range E_{p} = 27 to 54.1 MeV: see (1981AJ01). 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 ^{14}O_{g.s.}: see ^{17}F in (1982AJ01). For cross sections for the production of γrays from the decay of ^{14}N*(2.31, 5.11) at E_{p} = 40, 65 and 85 MeV see (1987LA11). For reaction (b) see (1986VDZY, 1987VD1A) and (1986GO28; theor.).
Angular distributions have been measured at many energies up to E_{d} = 40 MeV: see (1981AJ01). The yield of the isospin forbidden α_{1} group [to ^{14}N*(2.31)] has been studied for E_{d} = 2 to 15 MeV: the intensity of the group is strongly dependent on E_{d} and on the angle of observation. The α_{1} reaction appears to proceed almost exclusively by a compoundnuclear 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%. At E_{d} = 50 MeV, the intensity of ^{14}N(2.31) is 0.1  0.2% that of ^{14}N_{g.s.}. See also ^{18}F in (1987AJ02), (1985KA1A), (1985HA38, 1986DU1K; applied) and (1986SI1D; computer).
See (1988CA26; astrophys.).
