
^{16}N (1977AJ02)(See Energy Level Diagrams for ^{16}N) GENERAL: See also (1971AJ02) and Table 16.3 [Table of Energy Levels] (in PDF or PS). Model calculations: (1971AR1R, 1973RE17, 1973SI1G, 1975RA1T). Reactions involving muons: (1971GR1U, 1971LA17, 1973JO17, 1973KA30, 1973NA28, 1975FU1F, 1975PA01). Reactions involving pions: (1970AL22, 1971EI01, 1971GU13, 1971SR03, 1973CA25, 1973KA1D, 1973LA1G, 1973LA1H, 1973RE10, 1973SR02, 1974LI15, 1974SZ04, 1975RA1R, 1976TR1A). Other topics: (1971AR02, 1971SR03, 1972EV03, 1973KO1D, 1973RE17, 1973SI1G, 1973WI15, 1974MA1E, 1974SHYR, 1974VA24, 1975BE31, 1975FE1A, 1976NI1E). Mass of ^{16}N: the atomic mass excess of ^{16}N is 5681.7 ± 2.3 keV (A.H. Wapstra, private communication).
The halflife of ^{16}N is 7.13 ± 0.02 sec: see Table 16.3 (in PDF or PS) in (1971AJ02). See also (1975SA1D). From the character of the beta decay [see Table 16.23 (in PDF or PS)] it is concluded that ^{16}N_{g.s.} has J^{π} = 2^{}: see ^{16}O. The beta decay of ^{16}N*(0.12) [J^{π} = 0^{}, τ_{1/2} = 5.26 ± 0.05 μsec] to ^{16}O_{g.s.} has been studied: the βdecay rate λ_{β} = 0.43 ± 0.10 sec^{1}. Comparison of this value with the rate of the inverse muoncapture reaction in ^{16}O yields 13 ≤ g_{p}(q^{2} ≈ M^{2}_{μ}) ≤ 20 for the inducedpseudoscalar form factor (1975PA01).
The yields of t_{0} and of α_{0}, α_{1} and α_{2} have been measured for E(^{7}Li) = 4 to 14 MeV at 0°: several broad peaks are observed (1971WY01). The yields of α_{0} and α_{2} have also been studied for E(^{7}Li) = 3.3 and 5.0 to 6.2 MeV (1969SN02). The cross section for reaction (c) rises monotonically for E(^{7}Li) = 1.1 to 4 MeV (1957NO17, 1959NO40).
Angular distributions have been obtained at E(^{7}Li) = 16 MeV to ^{16}N*(3.36, 3.52, 3.96, 4.32, 4.39). The σ_{t} for ^{16}N*(3.36, 3.96, 4.32, 4.39), whose J^{π} are known, follow the 2J_{f} + 1 relation. From the σ_{t} for ^{16}N*(3.52) it follows then that J = 2 if it is a single state or J = 0 and 1 (with one of the two states having odd parity) if the group corresponds to two unresolved states (1975FO10). See also (1974KO1G), and see (1971AJ02) for a discussion of the earlier work of (1966MC05).
See (1966MC05).
See (1966MC05) and (1969TH01: E_{x} = 297.6 ± 0.9 and 397.8 ± 1.0 keV).
Not reported.
Not reported.
The cross section has been measured for 1.2 < E_{d} < 2.6 MeV. It shows some evidence of structure (1964NE09). See also (1971AJ02).
Observed resonances in the yield of n_{0} are displayed in Table 16.4 (in PDF or PS) (1961CH14, 1963IM01). The yields of n_{1+2}, n_{3} have been measured by (1967LA11) for 2.9 < E_{d} < 3.1 MeV. Polarization measurements are reported for E_{d} = 1.28, 1.55 and 1.88 MeV (1973NI01; n_{0}) and 2.00 to 3.30 MeV (1974ME32; n_{0}, n_{1+2}, n_{3}). See also ^{15}N in (1976AJ04).
The cross section of the γrays to ^{15}C*(0.74) rise monotonically for 2.7 < E_{d} < 3.4 MeV where it is ≈ 75 mb (1962CH14). Observed resonances are shown in Table 16.4 (in PDF or PS) (1956DO37). See also ^{15}C in (1976AJ04).
Excitation functions for elastic scattering have been measured for E_{d} = 4 to 10 MeV. A resonance is observed at E_{d} = 4.50 ± 0.05 MeV, Γ_{cm} = 180 keV, l_{d} = 4, J^{π} = 3^{+}, (4^{+}, 5^{+}) (1973CO31). See also ^{14}C in (1976AJ04).
See (1976WE01) and ^{13}C in (1976AJ04).
See ^{12}B in (1968AJ02).
Not reported.
Proton groups have been observed to ^{16}N states with E_{x} < 12 MeV and angular distributions (with E(^{3}He) ≤ 15 MeV) lead to the J^{π} assignments shown in Table 16.5 (in PDF or PS) (1966GA08, 1968HE03, 1972FR05). See also (1975FO06) and (1971AJ02).
At E_{α} = 46 MeV the angular distributions of five deuteron groups [see Table 16.5 (in PDF or PS)] have been determined: the most strongly populated state is the 5^{+} state, ^{16}N*(5.73) (1969LU07).
Angular distributions are reported at E_{t} = 1.8 MeV (1964SC09) and at 12 MeV (1966HE10, 1975CR02): see Table 16.6 (in PDF or PS) for the observed proton groups. See also (1976AL16) and (1970EL17; theor.).
The thermal cross section is 24 ± 8 μb (1973MU14, 1974SH1E).
The scattering amplitude (bound) a = 6.5 ± 0.2 fm [recommended by (1973MU14)]. The total cross section has been measured for E_{n} = 0.4 to 32 MeV: see (1971AJ02, 1976GAYV) and (1971ZE02). Observed resonances and parameters derived from Rmatrix and phaseshift analyses of these data, angular distributions and polarization measurements are displayed in Table 16.7 (in PDF or PS) (1971DO06, 1971ZE02). See (1971AJ02) for the earlier work, (1972LA1F) and (1971BA95, 1972AG02, 1972BA2C, 1972LI13, 1973BA74, 1973MO16, 1974AY01, 1974HO1L, 1975BA61, 1975MO10, 1975RO31; theor.).
See (1966PR1A, 1971PR09, 1976GAYV). See also (1972ED01, 1974BO1E).
See (1971AJ02).
Levels derived from observed proton groups and γrays are listed in Table 16.8 (in PDF or PS). Gamma transitions are shown in the inset of Fig. 2: (1971PA28) report that the branchings of ^{16}N*(0.40) to ^{16}N*(0, 0.12, 0.30) are, respectively, (26.6 ± 0.6)%, (73.4 ± 1.6)%, and ≤ 2 × 10^{3}% [(1963GI11) had reported a (5 ± 2)% branch for the latter transition]. The 0.30 → 0.12 transition is ≤ 10^{2}% (1971PA28). The mean life of ^{16}N*(0.12) is 7.58 ± 0.09 μsec (1967BE14); together with the angular distribution analyses this leads to J^{π} = 0^{} for the state. The very strong evidence for J^{π} = 2^{}, 3^{} and 1^{}, respectively, for ^{16}N*(0, 0.30, 0.40) is reviewed in (1971AJ02). See also (1972LI13, 1973BA74, 1973MO16, 1975BA61, 1975MO10; theor.) and reaction 1.
Not reported.
Not reported.
See (1969BR1D).
See ^{16}C.
See (1971AJ02) and (1976KI1D).
At E_{t} = 23.5 MeV ^{16}N*(0, 0.30) [J^{π} = 2^{}, 3^{}] are strongly populated relative to ^{16}N*(0.12, 0.40) [0^{}, 1^{}]. This suggests that the 2^{} and 3^{} states in ^{16}F are those that are strongly populated in the ^{16}O(^{3}He, t)^{16}F reaction [^{16}F*(0.42, 0.72)] and that the other two states in ^{16}F [^{16}F*(0, 0.20)] are 0^{} and 1^{} [the ordering within the 2^{} and 3^{}, and the 0^{} and 1^{} states, in ^{16}F is ambiguous] (1974FL06). See also ^{16}O(^{3}He, t) in ^{16}F.
A comparison has been made at E_{d} = 52 MeV of the population of states in this reaction and in the mirror (d, t) reaction in order to identify T = 1 states in ^{16}O and in order to study the mass dependence of the 1p spinorbit splitting: see reaction ^{17}O(d, t) in ^{16}O (1974MA23). See also (1973WA1E) and (1976SC1H; theor.).
At E_{p} = 43.7 MeV, the angular distribution of the ^{3}He nuclei corresponding to a state at E_{x} = 9.9 MeV fixes L = 0 and therefore J^{π} = 0^{+} for ^{16}N*(9.9): it is presumably the T = 2 analog of the ground state of ^{16}C. Some lowerlying T = 1 states were also observed (1964CE05). See also (1970OL1B, 1972OH1B).
Fortythree αparticle groups have been observed at E_{d} ≤ 12 MeV, corresponding to states of ^{16}N with E_{x} < 10.3 MeV: see Table 16.8 (in PDF or PS) (1966HE10, 1970BO08, 1970BO09). ^{16}N*(8.82, 9.8, 10.06) may be related to nearly bound virtual states of 2s_{1/2} neutron with ^{15}N*(6.32, 7.30, 7.57) (1970BO08, 1970BO09). (1975AS02) find τ_{m} = 6.5 ± 0.5 psec for ^{16}N*(0.40) and g = 1.83 ± 0.13; M^{2} for the M1 transition to ^{16}N*(0.12) is 0.17 ± 0.02 W.u. See also (1969NI09) and ^{20}F in (1978AJ03).
See (1969NI09).
Angular distributions have been reported for E_{n} = 4.7 to 14.4 MeV: see (1971AJ02) for the earlier references and see (1972FO21; E_{n} = 5.85 MeV; α_{0+1+2+3}). See also ^{20}F in (1978AJ03).
