A=14N (1970AJ04)

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¹⁴N (1970AJ04)

(See Energy Level Diagrams for ¹⁴N)

GENERAL: See Table 14.7 [Table of Energy Levels] (in PDF or PS).

Model calculations: (1957HU1C, 1959BA1F, 1959BR1E, 1959OT1A, 1959SK1A, 1960PA08, 1960TA1C, 1960WA12, 1961BA1F, 1961BA1E, 1961FR1C, 1961TR1B, 1962IN1C, 1962TA1E, 1962WE1C, 1963KU1B, 1963NA04, 1963SE19, 1963TR02, 1963WA15, 1964AM1D, 1964BR1L, 1964FE02, 1964LO1B, 1964MA1G, 1964NE1E, 1964ST1B, 1964UL1A, 1965CO25, 1965GL09, 1966BO1R, 1966HA18, 1966HA31, 1966HE1E, 1966MAZY, 1966MI1G, 1966WI1E, 1967CO32, 1967EV1C, 1967KU1E, 1967LI06, 1967PA05, 1967SO1A, 1968CO13, 1968DE13, 1968EI1C, 1968GO01, 1968HO1H, 1968KU1E, 1968NO1C, 1968RA10, 1968SO1B, 1968ZH05, 1969UL03, 1969VA1C).

General calculations and reviews: (1960PA08, 1962MA1P, 1963BL1B, 1963VL1A, 1964LI1B, 1964MC1C, 1964TH03, 1964YO1B, 1965BE1B, 1965GI1B, 1965KO1D, 1965MA1N, 1966DA1E, 1966MAZY, 1966WI1E, 1966ZA03, 1967BI06, 1968FR03, 1968GA03, 1968HI1H, 1968LA1J, 1968RI1H, 1968RO1C, 1969AT1A, 1969FR1E, 1969WA1F).

Electromagnetic transitions: (1959FA1C, 1959WA16, 1959WA04, 1960WA12, 1962MO1A, 1962UN1A, 1963KU03, 1964HE1F, 1965BI10, 1966HA31, 1966WA1E, 1967KU1E, 1967PO1J, 1967WA1C, 1968RO1C, 1969VA1C).

Meson interactions: (1967BA2H, 1967BA78, 1967BU1D, 1967FO1A, 1967KO1D, 1967MI1B, 1968BA2G, 1968BA1M, 1968BA48, 1968CH1F, 1968GO1T, 1968KO1C, 1968NO1A, 1968RI1H, 1968TA1C, 1968WI1B, 1968ZU1A, 1969CH1C, 1969MO1E, 1969SA1L, 1969WU1A).

Spallation: (1965ZH1A, 1967AU1B).

Ground state: J = 1; μ = +0.40361 nm (1964LI14).

Q = 16 ± 7 mb (1960LI10).

1. (a) ⁹Be(⁶Li, n)¹⁴N Q_m = 14.504
(b) ⁹Be(⁷Li, 2n)¹⁴N Q_m = 7.251

Gamma rays due to the 3.95 → 2.31, 4.91 → 0, 6.21 → 2.31 and 6.44 → 0 transitions have been observed in these reactions and in reactions 6 and 19: E_γ = 1631.3 ± 1.3, 4913.8 ± 3.0, 3883.0 ± 1.9 and 6443.7 ± 1.8 keV, respectively. τ_m = 0.62 ± 0.08 psec for ¹⁴N*(6.44) [see also Table 14.12 (in PDF or PS)] (1969TH01). For reaction (b), see also (1957NO17).

2. ¹⁰B(α, n)¹³N Q_m = 1.060 E_b = 11.613

Resonances are reported at E_α = 1.507 ± 0.004 MeV (1961BA22) and at 1.64, 2.16, 2.26, 2.95, 4.53, 4.85 and 5.36 MeV: see Table 14.8 (in PDF or PS) (1953SH64, 1955SH46, 1956BO61, 1959GI47). See also (1969ED1C).

3. ¹⁰B(α, p)¹³C Q_m = 4.063 E_b = 11.613

Observed resonances in the yield of 3.09, 3.68, 3.85 and 0.17 [3.85 → 3.68] MeV γ-rays and of various proton groups are displayed in Table 14.8 (in PDF or PS) (1953SH64, 1954ST20, 1969GA01). Excitation functions have also been measured for E_α = 4.5 to 10 MeV (1969ED1C), 12.4 to 16 MeV (1967IV1B; p₀) and 9.5 to 26 MeV (1966SP08). See also (1959AJ76).

4. ¹⁰B(α, d)¹²C Q_m = 1.341 E_b = 11.613

Observed resonances below E_α = 2 MeV are exhibited in Table 14.8 (in PDF or PS) (1953SH64). Excitation curves have also been determined for E_α = 3.2 to 3.8 MeV (1960ON01), E_α = 12 to 24 MeV (d₀) and 18 to 25 MeV (d₁) (1967AL16). Clear resonance structure is not observed at these higher energies. See also (ED69D).

5. ¹⁰B(α, α)¹⁰B E_b = 11.613

The yield of 0.72 MeV γ-rays has been measured for E_α = 2.1 to 3.5 MeV: observed resonances are shown in Table 14.8 (in PDF or PS) (1969GA01).

6. ¹⁰B(⁶Li, d)¹⁴N Q_m = 10.141

At E(⁶Li) = 5 MeV, deuteron groups are observed to the ground state of ¹⁴N and to excited states at 3.95, 4.91, 5.10, 5.69, 5.83, 6.23, 6.44, 7.03, 7.97, 8.47, 9.00, 9.13, 9.41, 9.71, 10.09, 10.43 and 11.06 MeV.

The T = 1 state at 10.43 MeV is populated weakly ((1966MC05) and private communication). See also (1963MO1B, 1969CO1D). Branching ratios for the γ-decay of ¹⁴N states have been measured: see Table 14.9 (in PDF or PS) (1966CA07). See also reaction 1 (1969TH01). See also (1964CA18, 1965CA05, 1967CA1D), (1966BR1G) and (1965RO1M, 1966RO1E, 1968TA1N).

7. ¹⁰B(⁷Li, t)¹⁴N Q_m = 9.146

Triton groups corresponding to a number of ¹⁴N states have been observed at E(⁷Li) = 5 MeV: see (1966MC05) and reaction 6. The angular distribution of the ground state tritons has been measured at E(⁷Li) = 4.5 MeV by (1963MO1B). See also (1965CA05, 1967CA1D) and (1966RO1E).

8. (a) ¹¹B(³He, γ)¹⁴N Q_m = 20.735 E_b = 20.735
(b) ¹¹B(³He, n)¹³N Q_m = 10.182
(c) ¹¹B(³He, p)¹³C Q_m = 13.185
(d) ¹¹B(³He, d)¹²C Q_m = 10.463
(e) ¹¹B(³He, t)¹¹C Q_m = -1.999
(f) ¹¹B(³He, ³He)¹¹B
(g) ¹¹B(³He, α)¹⁰B Q_m = 9.122
(h) ¹¹B(³He, ⁶Li)⁸Be Q_m = 4.566

The capture γ-rays (reaction (a)) havre been studied for E(³He) = 1 to 3 MeV. The differential cross section (at 90°) for the γ₀ transition increases rapidly with energy from ≈ 0.002 μb/sr at 1 MeV to ≈ 0.5 μb/sr at 3.0 MeV. At the latter energy I_γ/I_γ₀ ≈ 0.22 ± 0.08. There is some evidence also for transitions to higher excited states of ¹⁴N (1965PU1B).

The excitation function at 0° in the range E(³He) = 1.5 to 5.6 MeV for neutrons corresponding to ¹³N_g.s. (reaction (b)) shows a broad peak at E(³He) = 4.15 MeV which may indicate the existence of a ¹⁴N state at E_x ≈ 24.0 MeV, Γ ≈ 1 MeV (1966DI04). The excitation function for reaction (b) has also been measured for E(³He) = 6 to 18 MeV (1967HA20). See also (1964DI1C, 1965BR42).

Yield curves for protons (reaction (c)) have been measured for E(³He) = 3.0 to 5.5 MeV (p₀, p₁, p₁ + p₂ + p₃): 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(³He) = 6 to 18 MeV (1967HA20) and 10 to 30 MeV (1965BR42). See also ¹³C, and ¹¹C and ¹²C in (1968AJ02). For reaction (f), see (1968PA1Y).

The excitation functions of α-particle groups (α₀, α₁, α₂, α₃) (reaction (g)) have been measured for E(³He) = 2.2 to 5.5 MeV. No significant resonance behavior is seen except for the α₂ group which, in the 15° excitation function, exhibits a resonance at E(³He) = 4 MeV, Γ ≈ 1 MeV (1965FO06). See also ¹⁰B in (1966LA04). The excitation function for the reaction ¹¹B(³He, ⁶Li_g.s.)⁸Be_g.s. has been measured for E(³He) = 1.4 to 5.8 MeV: no pronounced compound nucleus effects are observed (1967YO02, 1967YO1C).

9. ¹¹B(α, n)¹⁴N Q_m = 0.157

Angular distributions have been measured for E_α = 2.4 to 3.7 MeV (1966MA04; n₀), 3.4 to 3.7 MeV (1966MA04; n₁), 2.1 to 5.4 MeV (1962CA05; n₀) and 13.5 and 13.9 MeV (1962KJ03; n₀, n₂). See also (1959HE1B) and (1959AJ76).

10. ¹¹B(⁶Li, t)¹⁴N Q_m = 4.942

At E(⁶Li) = 4.5 MeV, the angular distributions of the triton groups to ¹⁴N*(0, 2.31, 3.95) have been measured (1963MO1B). See also (1965CA05).

11. ¹²C(d, γ)¹⁴N Q_m = 10.272

The capture cross section is reported to be ≈ 0.6 ± 0.2 μb at E_d = 1 MeV (1961KN03): at E_d = 1.5 MeV it is < 1 μb (1955AL16).

12. (a) ¹²C(d, n)¹³N Q_m = -0.281 E_b = 10.272
(b) ¹²C(d, p)¹³C Q_m = 2.722

Resonances in the yields of neutrons and protons are displayed in Table 14.10 (in PDF or PS). Recent measurements of the yields of neutrons and protons are listed in Table 14.11 (in PDF or PS). See also (1965WI11, 1968CO04, 1969RO1R) and (1959AJ76).

Angular distributions of neutrons and protons have been reported at many of the energies listed in Table 14.11 (in PDF or PS). Except at very low energies, direct interaction is the predominant mechanism although resonances are observed for the first few MeV (see Table 14.10 (in PDF or PS)) and fluctuations persist to 12 MeV (1963EV04). See also (1955WI43), (1959AJ76), ¹³C and ¹³N. At E_d = 2.50 MeV (¹⁴N* = 12.41) the (d, p₃γ) angular correlation is undistorted. This is an example of a resonant direct reaction due to a single-particle state (1966KA05).

Polarization measurements are summarized in Table 14.12 (in PDF or PS). See also (1968BA2R, 1968BA47; theor.) (reaction (a)), and (1959AL08, 1962GR10, 1963BE1M, 1966SK1A, 1967GR1L; exp.), (1967CI1A, 1967KH1A, 1968BA2R, 1968BA47, 1969PE1N, 1969PE1L; theor.) (reaction (b)). See also the reviews by (1961GO1K, 1963HA1G, 1966DA1B, 1966MI1E).

For reaction (a) see also (1959BR75, 1966WY01, 1967SC43, 1967WY02; exp.) and (1961MA1E, 1964CA1F, 1967HO1K, 1968NO1C; theor.). For reaction (b) see also (1963GE03, 1967AU05, 1967MO1P, 1967TI1A, 1968NO1C, 1969PE09 ). For a discussion of sequential decay, see (1963PI04) and ¹³C and ¹³N.

13. ¹²C(d, d)¹²C E_b = 10.272

Reported resonances are displayed in Table 14.10 (in PDF or PS). Recent measurements of yields of scattered deuterons are listed in Table 14.11 (in PDF or PS). See also (1961CI08, 1962GR10, 1963GE03, 1965BA1W, 1967AU05, 1968BA2P, 1968GO1N), and (1965SA1H, 1966BA60, 1967HO1K, 1969IW1D). See also ¹²C in (1968AJ02) and (1959AJ76).

Polarization measurements are summarized in Table 14.12 (in PDF or PS). See also (1963ZA1B, 1965CA05, 1967RU1A; theor.).

14. ¹²C(d, t)¹¹C Q_m = -12.462 E_b = 10.272

The cross section rises from ≈ 0.1 mb at E_d = 16 MeV to ≈ 10 mb at 20 MeV (1955WI43). See also ¹¹C in (1968AJ02).

15. ¹²C(d, α)¹⁰B Q_m = -1.341 E_b = 10.272

Excitation functions have been measured for E_d = 5 to 29 MeV: see Table 14.11 (in PDF or PS).

Resonant structure has been reported by (1966PA1J) and (1968JA09): see Table 14.10 (in PDF or PS). Angular distributions have been measured at many of the above energies and analyzed by DWBA: see (1968KL06, 1969YA1C) and ¹⁰B in (1966LA04). See also (1963PE07, 1967HO1K).

The yield of the α₂ group (to ¹⁰B*(1.74) [J^π = 0⁺; T = 1] is typically < 1% of the intensity of the groups to the neighboring T = 0 states in the range E_d = 9 to 12.5 MeV. This is partly due to isospin conservation and partly to the J^π selection rule involved in this transition. When the latter effect is calculated and the corresponding factor removed, the intensities of the T = 1 α₂-groups range from ≈ 10% of the intensities of the T = 0 α-groups at E_d = 9 MeV to ≈ 1-2% at E_d = 11 MeV. Above E_d = 11.5 MeV, the yield of the α₂ group increases slightly indicating perhaps a direct-interaction mechanism involving isospin mixing at the surface of the nucleus (1966ME09). [See, however, below). The mixing might also occur through Coulomb excitation during the d-capture or the α-emission (1966ME09). Some fluctuations in the cross sections, with widths of a few hundred keV, are observed at forward and backward angles. Ericson fluctuations may be involved (1966ME09). The data of (1966ME09) have been interpreted as indicating an intermediate structure resonance corresponding to E_x ≈ 18 MeV, Γ ≈ 2 MeV [J^π = 3^-], whose doorway state is a single-particle cluster resonance in either, or both, the entrance or exit channels (1968NO1C). However, (1969SM03) find that the broad structure reported by (1966ME09) at E_d ≈ 13 MeV can be resolved into at least three separate peaks, in contradiction to the predictions of (1968NO1C). Both the angular distributions and the excitation functions can be interpreted in terms of a few resonant states of ¹⁴N [l = 4 and 5 account for most of the cross section at E_d ≈ 12.5 MeV], without introducing any large direct reaction amplitudes (1969SM03). See also (1968NO1C).

16. ¹²C(t, n)¹⁴N Q_m = 4.015

Angular distributions of the n₀, n₁ and n₂ groups have been measured at E_t = 1.7 MeV (1966MA2G). At E(¹²C) = 12 to 20 MeV, the lifetimes of ¹⁴N*(5.11, 5.83) have been determined using recoil distance method: τ_m(5.11) = 12.4 ± 1.4 psec, τ_m(5.83) = 18 ± 2 psec: see Tables 14.9 (in PDF or PS) and 14.13 (in PDF or PS). The 5.11 → 0 transition is enhanced by 2.2 ± 0.7 W.u. The allowed M2 5.11 → 2.31 transition has |M|² = 0.83 ± 0.14 W.u. while the isospin forbidden part of the 5.11 → 0 transition has |M|² = (3.3 ± 1.3) × 10^-3 W.u. (1968AL12). See also (1966AL11).

17. ¹²C(³He, p)¹⁴N Q_m = 4.779
Q₀ = 4.7763 ± 0.0015 (1967OD01);
Q₀ = 4.806 ± 9 (1964MA57);
Q₀ = 4.787 ± 10 (1962SH21);
Q₀ = 4.764 ± 7 (1959YO25);
Q_2.31 = 2.4684 ± 0.0010 (1962BA26).

Many proton groups have been observed: see Table 14.14 (in PDF or PS). At E(³He) = 20 MeV angular distributions of the protons corresponding to states with 0 < E_x < 12.6 MeV have been measured by (1968MA29) and analyzed using the distorted-wave calculations of (1965GL09) and spin-independent interaction potential. L-values have been assigned and are displayed in Table 14.14 (in PDF or PS).

It is pointed out that in this reaction unnatural parity states of T = 1 are not allowed: the proton groups corresponding to the 0^- 8.80-MeV state and the 2^- 9.51-MeV state, both of which are T = 1, are not observed (1967MA1G, 1968MA29). Angular distributions have also been obtained at many other energies: see (1965GR1R: 1 - 1.8 MeV; p₀, p₁, p₂), (1963LU01, 1963LU1F, 1964LU1B: 2.3 - 3 MeV; p₂), (1964KU05: 2.5 - 4.9 MeV; p₀ → p₉), (1969HA49: 3.0 - 9.2 MeV; p₀, p₁: 3.0 - 11 MeV; p₂ → p₄: 5.1 - 11 MeV; p₅ → p₉), (1967CL1C: 3.5 MeV; p₀ → p₈), (1966BL01: 5.1 MeV; p₂ → p₆), (1968LA19: 5.3 - 5.5 MeV; p₁, p₂, p₃, p₅), (1965FU16: 6.6 - 10.7 MeV), (1960PR12: 13.9 MeV; p₀, p₁, p₂), (1969HO23: 15 MeV: 0 < E_x < 12.8 MeV), (HO66, 1967FO1E: 15 MeV), (1968MA46: 25.3 MeV: 0 < E_x < 9.5 MeV) and (1959AJ76) for a listing of the earlier work. See also ¹⁵O. The parity of ¹⁴N*(6.44) is even from angular distribution measurements of protons and γ-rays at the E(³He) = 2.99 MeV resonance (1964KU05).

The γ decay of many states has been studied: Table 14.9 (in PDF or PS) displays observed branching ratios and radiative widths (1964WA09, 1965NE06, 1965RI02, 1965WA06, 1966GO15, 1967CH19, 1967GA12, 1967OL02, GA69J, 1969HA49). A very accurate value of the excitation energy of ¹⁴N*(5.11) is derived from E_γ: E_x = 5.10587 ± 0.00018 MeV (1967CH19). p-γ angular correlations have been measured at many energies. The results demand J = 0 or 1 for ¹⁴N*(4.91) and J = 2 for ¹⁴N*(5.11). The ground state transition for the latter contains E1, M2 and E3 components (1959WA04, 1965BL04, 1965NE06, 1966GO15), J = 2 for ¹⁴N*(7.03) and the angular correlation of the 2.51 MeV γ-ray (8.96 → 6.44) indicates J ≤ 5 for ¹⁴N*(8.96) (1967BL22). J^π = 5⁺ (1967GA12). See also (1963LU01, 1963LU1F, 1964LU1B) and Table 14.9 (in PDF or PS). Polarization measurements lead to J^π = 0^-, 1^- for ¹⁴N*(4.91) and odd parity for ¹⁴N*(5.11, 5.83) (1963BE33, 1968BL09). The parity of ¹⁴N*(6.21) is even (1964WA09). An analysis of elastic ³He, the angular distribution of the protons to ¹⁴N*(6.44) and of the subsequent ground state γ-rays at E(³He) = 2.99 MeV (¹⁵O*(14.46)) leads to even parity for ¹⁴N*(6.44) (1964KU05). The angular correlation of internal pairs is consistent with E2 radiation (1964WA09) for the 6.44 → 0 transition.

Measurements of mean lifetimes are displayed in Table 14.13 (in PDF or PS) (1964BE12, 1965LO07, 1966LI07, 1967LI04, 1969GA16, 1970GA09). See also (1963BE33).

18. ¹²C(α, d)¹⁴N Q_m = -13.575

Angular distributions of deuterons corresponding to various states of ¹⁴N (see Table 14.15 (in PDF or PS)) have been measured at E_α = 42 to 53 MeV (1959BO40, 1960HA32, 1962CE01, 1962HA40, 1965PE03, 1967ZA01 ). See (1962CE01, 1963GL1C, 1965GL09) for discussions of the analysis. The known T = 1 states are not excited in this reaction: see Table 14.15 (in PDF or PS) and (1960HA32, 1965PE03, 1967ZA01, 1968NO1C). [It should be noted that in addition to isospin conservation, angular momentum and parity considerations would also inhibit the excitation of the J^π = 0⁺; T = 1 2.31-MeV state; see, e.g., (1960HA32).] No evidence is seen at E_α = 42 MeV for deuterons in the J^π = 0⁺; T = 1 singlet state leading to the excitation of the 2.31-MeV state: d-bar₁/d₀ = 5 × 10^-3 (1967CR1G, 1969BR1N). 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 (1962HA40, 1966RI04).

Comparison of the angular distribution of ground state deuterons (E_α = 41.7 MeV) with that of the ground state alphas from the ¹⁴N(d, α)¹²C reaction (E_d = 20 MeV) leads to an upper limit of 3% for the time reversal non-conserving fraction of the Hamiltonian (1959BO40, 1959HE1C).

See also (1964NA1E, 1965PE17, 1966BR1G, 1967OG1A) and (1961EL1A, 1968ZE1B; theor.).

19. ¹²C(⁶Li, α)¹⁴N Q_m = 8.800

At E(⁶Li) = 20 MeV, α-groups corresponding to most of the T = 0 states with E_x < 12.7 MeV are reported. See Table 14.15 (in PDF or PS). The spectrum is dominated by the α-group corresponding to the 5⁺ state at 9.0 MeV (1968ME10). See also (1962HO06, 1967DZ01). The α₁ group to the J^π = 0⁺; T = 1 state at 2.31 MeV has been observed. Its intensity ( < 3% of α₀) decreases sharply from E(⁶Li) = 4 to 5.5 MeV, while the intensities of the α₀ and α₂ groups (to T = 0 states) increase rapidly. It is suggested that broad levels at the higher excitation energies corrrespond to such short lifetimes that the Coulomb forces do not have enough time to change the relative amountss of various isospin components in the compound nucleus wave function (1965CA06). See also (1962HO06, 1967DZ01).

Angular distributions of α-particles have been reported for E(⁶Li) = 2.0 and 2.4 MeV (1966BE07; α₀, α₂), 3.0 MeV (1963BA08; α₀), 3.2 to 4.0 MeV (1962HO06; α₀, α₁, α₂), 4.0 to 5.5 MeV (1965CA06; α₁), 4.5 to 5.5 MeV (1966HE05; α₀, α₂) and 20 MeV (1968ME10: see Table 14.15 (in PDF or PS)).

Doppler-shift attenuation measurements have led to the determination of τ_m for the 6.44 MeV state: (0.63 ± 0.08) psec (1969TH01): see Table 14.13 (in PDF or PS) and reaction 1. See also Table 14.9 (in PDF or PS).

See also (1960SH01, 1960SH05, 1961MA1K, 1961MA33, 1962LI08, 1963OL1B, 1964CA18, 1967CH34, 1967OG1A, 1968DA20) and (1962IN1C, 1963TA1B, 1966RO1E, 1966RO1F, 1968HO1J, 1968RO1D; theor.).

20. (a) ¹²C(⁹Be, ⁷Li)¹⁴N Q_m = -6.421
(b) ¹²C(¹¹B, ⁹Be)¹⁴N Q_m = -5.547

At E(¹¹B) = 115 MeV, the ⁹Be spectrum is dominated by groups corresponding to the ¹⁴N 5⁺ state at E_x = 8.96 MeV, the 4⁺ state at E_x = 12.79 MeV and to the 6^- state at E_x = 15.10 MeV, the levels also strongly populated in the ¹²C(α, d)¹⁴N reaction (see reaction 18) (1966PO1E, 1967PO1E ) and private communication). Groups to ¹⁴N*(0, 3.95, 5.83, 6.44, 10.81) are also reported (J.E. Poth, private communication). See also (1967VO1A). The angular distributions of the two strong groups are smoothly varying, exponential functions of angle, and have been fitted, in terms of a surface-diffuseness parameter, using a diffraction model (1965SA07). See also (1965DA1E, 1965GR1F) and (1964FL1D, 1964NA1E, 1967OG1A, 1968RO1D, 1969RO1G, 1969BR1D). For reaction (a), see (1969RO1G).

21. ¹²C(¹²C, ¹⁰B)¹⁴N Q_m = -14.916

See (1962CH01).

22. ¹²C(¹⁴N, ¹²C)¹⁴N

At E(¹⁴N) = 28 MeV, excitation of ¹⁴N*(0, 3.95, 4.91, 5.11) and some higher states is reported. The total cross section for excitation of the T = 1 state at E_x = 2.31 MeV is < 60 μb (1961HA04). See also (1968HU1H, 1969BR1D, 1969HE06).

23. ¹²C(¹⁸F, ¹⁶O)¹⁴N Q_m = 2.745

See (1968RO1D).

24. ¹³C(p, γ)¹⁴N Q_m = 7.550

Observed resonances are displayed in Table 14.16 (in PDF or PS). The decay schemes of various levels of ¹⁴N, as derived from the γ-spectra in this and other reactions are exhibited in Table 14.9 (in PDF or PS) (1953WO41, 1959WA04, 1960HE14, 1960RO13, 1960RO23, 1963PR03, 1963RO17, 1964RO03, 1965DE19, 1967RI1D, 1968BL1E, 1968RI1R).

The low-energy capture cross-section yields an extrapolated σ-factor at E_p = 25 keV (cm), S₀ = 6.0 ± 0.8 keV · b (1960HE14). See also (1963BR14, 1964FO1A, 1966BA2P, 1967FO1B). 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).

Direct radiative capture of protons into the lowest three odd-parity states ¹⁴N*(4.91, 5.11, 5.69, 5.83) has been studied by (1964TR04). See also (1963RO17).

The angular distribution of the γ-rays at the E_p = 0.45 MeV resonance (¹⁴N* = 7.97 MeV) is consistent with J^π = 2^- (1960HE14). The width of the E_p = 0.55 MeV resonance and the isotropy of the γ-rays (1949DE1A, 1953WO41) indicate s-wave formation of ¹⁴N*(8.06): J^π = 1^- from ¹³C(p, p)¹³C. The decay properties of this state (see Table 14.9 (in PDF or PS)) show that the ground state transition is an uninhibited E1 transition, and thus that ¹⁴N*(8.06) has T = 1 (1953CL39) but with a strong T = 0 admixture [as shown by a 2% (8.06 → 2.31) transition] (1956LE28, 1957BR25, 1957WI27). The strong transition 8.06 → 5.69 admits either E1, ΔT = 1 or M1, ΔT = 1. Since the transition 5.69 → 2.31 is observed, ¹⁴N*(5.69) cannot have J^π = 0⁺, and 2⁺ is excluded by the strength of the 8.62 → 5.69 transition. It appears then that ¹⁴N*(5.69) has J = 1: see (1956LE28, 1957WI27, 1959WA04).

Anomalies in the capture cross section ("midget resonances") are observed at E_p = 1.01, 1.52 and 1.70 MeV: see Table 14.16 (in PDF or PS). The predominant γ-decay at the first resonance, ¹⁴N*(8.49), is to the 5.10 MeV state. The angular distribution of the γ-rays and ωΓ_γ are consistent with J^π = 4^-; T = 0 for ¹⁴N*(8.49). The γ-decay of the second state, ¹⁴N*(8.96), is predominantly to the 6.44 MeV state: it's J^π = 5⁺. The third state decays primarily to the ground state: the angular distribution of the γ-rays is consistent with J^π = 2^-; T = 0 for ¹⁴N*(9.13) (1965DE19).

The narrow E_p = 1.16 MeV resonance, ¹⁴N*(8.62) [J = 0⁺ from ¹³C(p, p)¹³C] shows strong transitions to ¹⁴N*(0, 3.95, 5.69): hence T = 1 (1959WA16). The strong transition 8.62 → 3.95 requires dipole radiation and hence J = 1 for the latter (1959WA04) while the strength of the transition 8.62 → 6.21 and the angular correlation in the cascade 8.62 → 6.21 → g.s. is consistent with J^π = 1⁺; T = 0 for ¹⁴N*(6.21): see (1956GO1L, 1956GO39, 1957GA1B, 1957GO30, 1957WI27, 1959GA05).

The E_p = 1.25 MeV resonance, ¹⁴N*(8.80) [J^π = 0^- from ¹³C(p, p)¹³C] has a large γ-width consistent with E1 radiation and T = 1 (1953WI1A). At E_p = 1.47 MeV, the plane polarization of 0.73 MeV γ-rays (from 5.83 → 5.11) suggests odd parity for both these states (1962RO21).

Angular correlation and angular distributions of γ-rays at the E_p = 1.75 MeV resonance, ¹⁴N*(9.17), indicates J = 2⁺ for that state, J = 3 for ¹⁴N*(6.44) and J = 2 for ¹⁴N*(7.03) (1959RO54, 1959WA04, 1960RO13, 1960RO23, 1963PR03). The angular distribution of the 2.73 MeV γ-rays (9.17 → 6.44) suggests odd parity for ¹⁴N*(6.44) (1961SE03, 1963PR03).

Marked variations are observed in the (cosθ) term at E_p = 2.75 and 2.90 MeV [¹⁴N*(10.09) and (10.23)] (1960RO23). The angular distribution of the γ-rays from the 10.23 → 2.31 transition (E_p = 2.88 MeV resonance) is consistent with J^π = 1⁺, assuming a single state at 10.23 MeV: M²(M1) leads to a T = 0 assignment (1963RO17). At the E_p = 3.11 MeV resonance [¹⁴N*(10.43)], the angular distribution of ground state γ-rays is consistent with J = 2 (1959WA16, 1960RO23): the similar decay characteristics of ¹⁴N*(10.43) and of the J^π = 2⁺; T = 1 state at E_x = 9.17 MeV suggest that the 10.43 MeV state is in fact also a J^π = 2⁺; T = 1 level (1964RO03).

The yield of γ₀ for E_p > 3.5 MeV shows a steady rise marked at first by pronounced resonances and then by broad structures most of which are related to levels seen in the inverse reaction (¹⁴N(γ, p)¹³C). The γ₁ yield (to ¹⁴N*(2.31)) is on the average only about a third the γ₀ yield with roughly constant cross section for E_p = 7 to 18 MeV. Only weak structure is observed (1967RI1D, 1968BL1E, 1968RI1R): see Table 14.16 (in PDF or PS).

See also (1959WA02, 1962WA1C), (1965FA1E, 1965MA1H; theor.) and (1959AJ76).

25. (a) ¹³C(p, p)¹³C E_b = 7.550
(b) ¹³C(p, p')¹³C*

The elastic scattering has been studied for E_p = 0.14 to 0.75 MeV (1960HE14), 0.45 to 1.60 MeV (1954MI05), 1.0 to 2.6 MeV (1966LA03), 1.5 to 3.4 MeV (1957ZI09, 1958ZI17), 2.6 to 5.0 MeV (1961KA04), 5 to 8.1 MeV (1965BA1W), and 7 to 11 MeV (1966SH1H): parameters of resonances observed in this reaction and in the ¹³C(p, γ)¹⁴N reaction are displayed in Table 14.16 (in PDF or PS). Angular distributions of elastically scattered protons have been measured at many of these energies.

The yield of γ-rays in reaction (b) has been measured for E_p = 3.6 to 5.0 MeV: the 3.1 MeV γ-yield shows broad resonances at E_p = 3.80, 4.1, 4.14 and 4.60 MeV while the 3.7 MeV γ-yield shows one resonance at E_p = 4.52 MeV (¹⁴N* = 11.07, 11.30, 11.39, 11.82 and 11.75 MeV, respectively) (1960BA35, 1961BA09): see Table 14.16 (in PDF or PS). The angular distribution of inelastic protons to ¹³C*(3.68) at the E_p = 4.52 MeV resoance leads to the assignment J^π = 1⁺ for ¹⁴N*(11.75) (1961BA09). The excitation functions for proton groups to ¹³C*(3.09, 3.68, 3.85) have been measured for E_p = 5 to 11 MeV (1965BA1W, 1966SH1H). See also (1962BE04).

Polarization measurements for elastically scattered protons are reported at E_d = 7 MeV by (1969GU02) and at E_p = 14.5 MeV by (1962RO20, 1965RO22, 1966RO1B, 1966RO1R). At E_p = 32.9 MeV, the polarization and asymmetry in the elastic scattering have been compared. They are equal to within 1%, and there is therefore no evidence for violation of time reversal invariance for strong interactions, at least for that part of the force which flips the spin of the proton (1968GR1K, 1969MA2D).

See also (1962WA1C, 1963GE03, 1964FO02, 1967AR1D), (1967HO1L, 1969WA11), (1964PF1A, 1966AM1B; theor.) and (1959AJ76).

26. ¹³C(p, n)¹³N Q_m = -3.003 E_b = 7.550

The yield of neutrons has been measured from threshold to E_p = 13.7 MeV: see (1959AJ76) and (1959BR06, 1960BA35, 1961DA09, 1961WO03, 1966DI03). Observed resonances are displayed in Table 14.17 (in PDF or PS). Angular distributions have been measured at many energies: over much of the energy range (below E_p = 10 MeV) there is pronounced backward peaking with a secondary maximum near 50° and no forward peak (1961DA09). The polarization of neutrons corresponding to ¹³N_g.s. has been studied for E_p = 6.9 to 12.3 MeV (1964WA1G, 1965WA02). See also (1962BE04, 1964CA1F, 1965VA23, 1969BA1N) and ¹³N.

27. ¹³C(p, d)¹²C Q_m = -2.722 E_b = 7.550

The yield of ground state deuterons has been determined for E_p = 5 to 11 MeV (1965BA1W, 1966SH1H). See also (1962BE04). A polarization measurement at E_p = 7 MeV is reported by (1969GU02). See also (1968TA1V) and ¹²C in (1968AJ02).

28. ¹³C(p, t)¹¹C Q_m = -15.185 E_b = 7.550

See (1968TA1V).

29. ¹³C(p, α)¹⁰B Q_m = -4.063 E_b = 7.550

Alpha-particle yields have been measured for E_p = 7 to 12 MeV (1963PE07, 1964FO02, 1966SH1H).

30. ¹³C(d, n)¹⁴N Q_m = 5.325

Observed neutron groups are exhibited in Table 14.18 (in PDF or PS). Recent angular distribution measurements are reported by (1969CH04: 0.5 to 0.8 MeV; n₃), (1961JA09: 1.2 MeV; n₀ → n₆), (1961ZD01, 1964WI03: 1.3 to 2.5 MeV; n₀, n₁, n₂), (1963BE05: 3.9 MeV; n₀, n₁, n₂, n₃ + n₄), (1966FU10, 1966SI02, 1967FU04: 5.5 and 6 MeV; many groups), (1968CO24: 7 to 12 MeV; n₀, n₁, n₂), and (1969VE1D: 11.8 MeV; n₀, n₁, n₂). See also (1960VA11, 1962SH19, 1963DE19). Comparison of relative spectroscopic factors here and in the ¹³C(³He, d)¹⁴N reaction [see Table 14.19 (in PDF or PS)] shows smaller values for the T = 1 state [¹⁴N*(2.31)] in this reaction than in the (³He, d) reaction (1966SI02, 1967FU04). Simple DWBA calculations would suggest that the factors would be the same in both proton pickup reactions. However, the dependence of the cross section magnitude on the T of the final state [the t · T term] appears to be energy dependent: see Table 14.19 (in PDF or PS) (1968CO24). See also (1967LE1F).

In the range E_d = 0.4 to 4.2 MeV, a single strong neutron threshold occurs at E_d = 0.422 ± 0.005 MeV (¹⁴N* = 5.691 ± 0.006) (1955MA76). See also (1965MA1K).

Observed γ-rays attributed to transitions in ¹⁴N are shown in Table 14.20 (in PDF or PS) (1952TH24, 1955BE62, 1955MA36, 1958RA13, 1966AL10). The decay of ¹⁴N*(5.69) is via ¹⁴N*(2.31) [63 ± 2%] and directly to ¹⁴N_g.s. [37 ± 2%]. τ_m [¹⁴N*(4.91)]<0.5 psec (1963AL21) [see also Tables 14.9 (in PDF or PS) and 14.13 (in PDF or PS)]. The angular correlation of internal pairs conclusively establish the parities of ¹⁴N*(4.91, 5.10, 5.69) as odd (1964WA05).

See also (1959CH28, 1959GO78, 1966EV1B), (1959NE1B, 1960AB02, 1964BA1G, 1966BA2R, 1966ST1L, 1967BA2J; theor.) and (1959AJ76). See also ¹⁵N.

31. ¹³C(³He, d)¹⁴N Q_m = 2.056
Q₀ = 2.070 ± 0.015 (1962SH21);
Q₀ = 2.048 ± 0.014 (1963SP1B);
Q₀ = 2.050 ± 0.015;
Q₁ = -0.265 ± 0.015 [E_x = 2.315 ± 0.022] (1959YO25).

Angular distributions have been obtained at E(³He) = 13 and 17 MeV (1966SI02: ¹⁴N*(0, 2.31, 3.95)), 15 MeV (1966HO15, 1969HO23: ¹⁴N*(0 → 9.17)), 17.8 MeV (1966EC1B: ¹⁴N*(0, 2.31, 3.95)) and 22 MeV (1969MA1R: ¹⁴N*(0, 2.31)). Relative spectroscopic factors for the first three states have been compared with those obtained in the ¹³C(d, n)¹⁴N reaction (1966HO15, 1966SI02): see reaction 30 and Table 14.19 (in PDF or PS). See also (1967LE1F). Spectroscopic factors for the higher states have also been obtained by (1966HO15), from a DWBA analysis. l-values for the observed groups are in agreement with those obtained by (1966FU10) in the (d, n) reaction: see Table 14.18 (in PDF or PS). See also (1965HE01, 1967BA1D).

32. ¹³C(α, t)¹⁴N Q_m = -12.264

Angular distributions have been obtained at E_α = 46 MeV of the tritons corresponding to the first seven states of ¹⁴N: the data are consistent with the assumption of a direct interaction in which a proton is transferred from the incident α-particle (1969FO1C).

33. ¹³C(¹¹B, ¹⁰Be)¹⁴N Q_m = -3.678

At E(¹¹B) = 113.5 MeV, ¹⁰Be groups are observed corresponding to ¹⁴N*(5.69 + 5.83), (8.80 + 8.91) and possibly to ¹⁴N*(12.2). The two lower transitions correspond to the addition of s_1/2 and d_5/2 protons to the ¹³C target core. States which were not excited would have required the excitation of the target core in addition to the transfer of a nucleon (1967PO13). See also (1969BR1D).

34. ¹³C(¹⁴N, ¹³C)¹⁴N

See (1968HU1H).

35. ¹⁴C(β^-)¹⁴N Q_m = 0.156

See ¹⁴C.

36. ¹⁴C(p, n)¹⁴N Q_m = -0.626

Neutron thresholds have been observed at E_p = 671.5 ± 0.5 and 3149.6 ± 1.1 keV (1956SA06) and at E_p = 4910 ± 8 keV (1960BA34) corresponding to the ground state of ¹⁴N and to excited states at 2.3119 ± 0.0012 and 3.952 ± 0.008 MeV. Angular distributions of the neutrons corresponding to ¹⁴N*(0, 2.31, 3.95) have been obtained for E_p = 6 to 14 MeV. At the highest energies these have been analyzed by using finite range DWBA, taking into account various isospin and spin factors. The ground state transition is not inhibited, whereas the ¹⁴C β-decay is. This requires spin-flip mechanisms such as a tensor interaction or particle exchange (1967WO05). See also (1969MA1G). Angular distributions are also reported at E_p = 20 and 30 MeV (1969SA1M; n₀, n₁, n₂). See also ¹⁵N.

37. ¹⁴C(³He, t)¹⁴N Q_m = 0.138

At E(³He) = 44.8 MeV, triton groups are observed corresponding to all he known levels of ¹⁴N with E_x < 7.1 MeV. Triton groups were also seen to unresolved states with E_x = 8.0 - 9.5 MeV, to ¹⁴N*(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 two-body interaction with an arbitrary spin-isospin exchange mixture. Dominant L = 0 transitions are found to ¹⁴N*(2.31, 3.95, 13.7), L = 1 to ¹⁴N*(5.11), L = 2 to ¹⁴N*(0, 7.03, 10.43) and L = 3 to ¹⁴N*(5.83) (1967BA13, 1968BA1E, 1969BA06). See also (1969MA1G) and reaction 45.

38. (a) ¹⁴N(γ, n)¹³N Q_m = -10.553
(b) ¹⁴N(γ, p)¹³C Q_m = -7.550
(c) ¹⁴N(γ, d)¹²C Q_m = -10.272
(d) ¹⁴N(γ, pn)¹²C Q_m = -12.497
(e) ¹⁴N(γ, α)¹⁰B Q_m = -11.613
(f) ¹⁴N(γ, nα)⁹B Q_m = -20.051
(g) ¹⁴N(γ, pα)⁹Be Q_m = -18.201

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 solely by the (γ, n) and (γ, p₀) processes: particle unstable excited states of ¹³C, ¹³N are believed involved (1969BE92). Over the interval E_γ = 20.0 to 20.5 MeV, the average cross section is 10.5 ± 4 mb (1959CA1C, 1960CA09). See also (1968CO13). The cross section for neutron production, reactions (a) and (d), exhibits maximum at E_γ = 22.5 MeV, Γ = 3.2 MeV, σ = 15.3 mb (1954FE16) [Γ = 3.8 MeV, σ = 14.5 mb (1960FA06)]. The cross section for reaction (a) shows a maxima at E_γ = 11.7, 13.2, 15.2, 19.5 and 22.8 MeV (1960KI02). [The peak cross sections for the two highest energy maxima are ≈ 1.8 and 2.8 mb, respectively; the widths are ≈ 2 - 3 MeV, estimated from the published curve.] Breaks in the (γ, n) activation curve are reported at E_γ = 11.07 MeV (1960GE06) and 11.49, 11.61, 12.39, 12.92, 13.28, 13.87, 14.62, 15.25, 16.35, 18.05 and 19.10 MeV (1959MU08, 1960MU02: ± 50 keV). See also (1959FU1A, 1960BA15, 1960KO05, 1960SA09, 1962GO1E, 1962KO23, 1963CO1D, 1963FU06, 1970LO1A).

Studies of reaction (b) indicate the involvement of ¹⁴N*(8.06, 9.17, 10.43) (1956WR22, 1960WA17) as well as of ¹⁴N states with E_x = 11.8, 13.0 and 15.2 MeV (1960WA17). See also (1959FU1A, 1960BA15, 1960KO05, 1962GO1E, 1962KO23, 1963FI1B, 1964ED01, 1964KO1D). For reaction (c), see (1964ED01). For reaction (d) see also (1959RE1A, 1960BA15, 1962GO1E, 1962KO23, 1963KO1B, 1964KO1D).

For reactions (e), (f) and (g) see (1956LI05, 1958MA1A, 1960BA15, 1960KO05, 1962GO1E, 1962MO16, 1964ED01, 1964TO1B). See also (1959AJ76).

39. ¹⁴N(γ, γ)¹⁴N

Resonant absorption measurements give Γ = 72 ± 10 eV (1965LU05), 77 ± 12 eV (1959HA11) for ¹⁴N*(9.17): ωΓ_γ = 14.5 ± 2 eV consistent with dipole radiation (1959HA11). (1966SW01) finds E_x = 7.029 ± 0.006 MeV for ¹⁴N*(7.03). The angular distribution of the scattered radiation is consistent with J = 2. Assuming that ¹⁴N*(7.03) decays entirely to the ground state [actually 98%: see Table 14.13 (in PDF or PS)], τ_m = 5.4 ± 0.5 fsec (1966SW01). The mean lifetime for ¹⁴N*(2.31) is 77 ± 18 fsec (1961SW01), 97 ± 30 fsec (1964BO22). For ¹⁴N*(8.06), (1956GR17, 1958GR97) finds Γ_γ = 10.5 ± 6 eV. See Tables 14.9 (in PDF or PS), 14.13 (in PDF or PS) and 14.21 (in PDF or PS).

An elastic scattering study shows a broad (several MeV wide) maximum centered around E_γ = 24 MeV and indicates a secondary maximum around 30 MeV (1967LO1B).

40. ¹⁴N(e, e)¹⁴N

The r.m.s. radius of ¹⁴N at E_e = 400 MeV is 2.58 ± 0.05 fm (1968DA1Q). See also (1964BI04). See also (1959ME24). Measurements of magnetic form factors at E_e = 100 to 180 MeV favor jj-coupling for ¹⁴N_g.s. (1966RA29).

Inelastic scattering (θ = 180°) gives evidence for the excitation of ¹⁴N*(8.91, 9.17, 10.43): the ground state Γ_γ are given in Table 14.21 (in PDF or PS) (1962ED02, 1963BA19, 1966KO08, 1968CL05). In addition (1968CL05) report the excitation of a state with E_x = 11.01 ± 0.07 MeV and (1966KO08) report structure at E_x = 11.7 and 12.7 MeV. Partial Γ_γ [for cascade transitions of ¹⁴N*(9.17, 10.43)] have been obtained by (1968CL05) and are shown in Table 14.9 (in PDF or PS). See also (1963GO04). Inelastic scattering is also reported to ¹⁴N*(2.3, 3.95, 5.1, 5.85, 7.05, 8.0) (1964BI09). See also (1964BI04). See (1962BA1D) for a general discussion. See also (1958CA1B, 1960PA08, 1963GU1A, 1967KA1A, 1969VI02).

41. ¹⁴N(n, n')¹⁴N*

Angular distributions of elastically and inelastically scattered neutrons are displayed in Table 14.23 (in PDF or PS). See also (1959AJ76) and ¹⁵N.

Observed gamma rays are displayed in Table 14.23 (in PDF or PS) (1969DI1B, 1969NY1A). See also (1959HA13, 1968CO1W). Lifetime measurements are reported in Table 14.22 (in PDF or PS) (1969NY1A).

42. (a) ¹⁴N(p, p')¹⁴N*
(b) ¹⁴N(p, 2p)¹³C Q_m = -7.550
(c) ¹⁴N(p, pd)¹²C Q_m = -10.272

Angular distributions of elastically and inelastically scattered protons have been measured and analyzed at a number of energies: see Table 14.23 (in PDF or PS). See also ¹⁵O and (1968OD1B). Observed inelastic proton groups are shown in Table 14.24 (in PDF or PS). The proton groups corresponding to ¹⁴N*(7.40, 7.60) reported by (1956BU16) are spurious: see (1964DO03, 1964EA04). See also (1963BR14, 1966ME1L). (1965DE21) reports the excitation of ¹⁴N states with E_x = 11.2 ± 0.2 and 12.8 ± 0.4 MeV, and the measurement of the angular distribution of the protons from the decay of ¹⁴N*(11.2). See also (1957HO34, 1961CL09, 1969CU1D) and (1962KA1E, 1962WA1D, 1965TA07, 1969MA1G, 1969WA11). See also (1959AJ76) and (1960WA12).

Reaction (b) at E_p = 19 MeV proceeds at least in part through an intermediate state in ¹⁴N at E_x ≈ 11.2 MeV (1965DE21). See also (1961CL09, 1965RI1A, 1966TY01) and (1965BE1E, 1965DE1P, 1967JA1E, 1967KO1P, 1969KO1J; theor.) and ¹³C. For reaction (c) see (1961CL09) and (1964BA1P, 1966JA1A; theor.).

43. ¹⁴N(d, d')¹⁴N*

Angular distributions of elastically and inelastically scattered deuterons have been obtained at a number of energies: see Table 14.23 (in PDF or PS). See also ¹⁶O in (1971AJ02). Inelastic deuteron groups are displayed in Table 14.24 (in PDF or PS). The deuteron group to the 0⁺; T = 1 state at E_x = 2.31 MeV is isospin forbidden: its intensity is 1 - 3% of the deuteron group to ¹⁴N*(3.95) for E_d = 7.7 to 10.2 MeV (1968DU1E). See also (1953BO70). The deuteron group to the T = 1 state ¹⁴N*(8.06) is also not seen: see Table 14.24 (in PDF or PS). See also general discussions in (1960WA12, 1966BR1G, 1968NO1C). See also (1968ME1E, 1969CU08).

44. ¹⁴N(t, t)¹⁴N

See (1964SC09).

45. ¹⁴N(³He, ³He')¹⁴N*

Angular distributions of elastically and inelastically scattered ³He particles have been determined by (1962SE13, 1964SE05, 1965AR1E, 1969BA06): see Table 14.23 (in PDF or PS). See also (1967KN1B).

At E(³He) = 44.6 MeV, twelve ³He groups are reported corresponding to states in ¹⁴N: see Table 14.24 (in PDF or PS) (1969BA06). The angular distributions were analyzed using a local two-body interaction with an arbitrary spin-isospin exchange mixture. A comparison of the cross sections of the reactions ¹⁴N(³He, t)¹⁴O_g.s., ¹⁴N(³He, ³He')¹⁴N*(2.31) and ¹⁴C(³He, t)¹⁴N_g.s. [which all correspond to transitions between identical initial and final states] shows that they are roughly equal, as would be expected fron charge independence, once detailed-balance, isospin coupling and phase-space correactions have been applied (1969BA06). See also (1968HO1C, 1968LE1G, 1969RA1B).

46. (a) ¹⁴N(α, α')¹⁴N*
(b) ¹⁴N(α, αp)¹³C Q_m = -7.550
(c) ¹⁴N(α, αd)¹²C Q_m = -10.272

Angular distributions of elastically and inelastically scattered α-particles have been measured for E_α = 11 to 104 MeV: see Table 14.23 (in PDF or PS). The intensity of the isospin-forbidden α₁ group to ¹⁴N*(2.31) is low. The highest intensities reported are 0.18 of the α₀ group and 0.4 of the α₂ group for E_α = 11.4 to 12.7 MeV (1966CH1E). Generally the intensity of the α₁ group is much smaller than that, typically a few percent of the α₀ or α₂ group: see (1959AJ76, 1966HA19): see also Table 14.23 (in PDF or PS).

Reduced transition probabilities are reported by (1966HA19): B(E2)↓/e² = 6.5 and 3.3 fm⁴, respectively for ¹⁴N*(3.95, 7.03); B(E3)↓/e² = 40 and 60 fm⁶, for ¹⁴N*(5.11, 5.83). See also (1962HA40, 1962JO14, 1963MI1C, 1969BA06), (1968FA1A), (1960WA12), (1968NO1C, 1968RA1C; theor.) and ¹⁸F in (1972AJ02).

At E_α = 22.9 MeV, reaction (b) to ¹³C_g.s. appears to involve twelve states of ¹⁴N with E_x = 8.4 to 13.2 MeV, while reaction (c) proceeds via five states with E_x = 11.5 to 12.9 MeV (1969BA17). See also (1967BE30, 1968KU1C).

47. ¹⁴N(⁹Be, ⁹Be)¹⁴N

See (1964KU1D, 1969BR1D).

48. ¹⁴N(¹²C, ¹²C)¹⁴N

See (1961NE04, 1962SM02, 1964KU1D).

49. ¹⁴N(¹⁴N, ¹⁴N)¹⁴N

See (1962SM02, 1968JA1N) and (1967BR1M, 1969VO1E).

50. ¹⁴N(¹⁶O, ¹⁶O)¹⁴N

See (1961NE04, 1968JA1P).

51. ¹⁴O(β⁺)¹⁴N Q_m = 5.144

The decay proceeds almost entirely to the J^π = 0⁺; T = 1 state of ¹⁴N at 2.31 MeV: see ¹⁴O. Measurement of the γ-ray energy from the decay of ¹⁴N*(2.31) leads to E_x = 2.31287 ± 0.00010 MeV for this state (1968FR08), 2.31289 ± 0.00010 MeV (1967CH19). The spectrum shape for the transition to ¹⁴N_g.s. differs markedly from the statistical shape. τ_m for ¹⁴N*(2.31) extracted from these data is 33 ± 3 fsec (1966SI05): see, however, Table 14.13 (in PDF or PS).

52. ¹⁵N(p, d)¹⁴N Q_m = -8.610

Angular distributions have been obtained for the deuterons corresponding to ¹⁴N*(0, 2.31, 3.95) (1961BE12: E_p = 18.6 MeV) and to ¹⁴N*(0 - 8.06, 8.62, 8.91, 8.96+8.98, 9.17 - 10.43, 10.81, 11.04, 11.24 + 11.30, 11.39 - 11.66, 11.75 + 11.81, 11.95, 12.23 + 12.29, 12.50, 12.61, 12.79 + 12.83, 13.16 + 13.23, 13.72) (1969SN04: E_p = 39.8 MeV). Spectroscopic factors were extracted by DWBA analysis of the l_n = 1 pickup angular distributions. Γ = 210 ± 30 keV for ¹⁴N*(13.75). Weak deuteron groups to ¹⁴N states at E_x = 6.70, 7.40 and 7.60 MeV are reported [see, however, reaction 54] (1969SN04).

53. ¹⁵N(d, t)¹⁴N Q_m = -4.577

Not reported.

54. ¹⁵N(³He, α)¹⁴N Q_m = 9.743

At E(³He) = 2.8 MeV, α-particle groups are observed to ¹⁴N states at E_x = 3.95, 4.91, 5.113 ± 0.008, 5.691 ± 0.008, 5.832 ± 0.008, 6.048 ± 0.012 [see, however, (1969HO23)], 6.224 ± 0.012, 6.436 ± 0.012, 7.032 ± 0.010, 7.97 and 8.06 MeV (1962CL12, 1962CL1D). The previously reported states at E_x = 6.70, 7.40 and 7.60 MeV are unobserved (1962CL12, 1969HO23). Angular distributions have been obtained at E(³He) = 2.8 MeV (1962CL12: to ¹⁴N*(3.95, 5.69, 5.83)), 15 MeV (1969HO23: to ¹⁴N*(0 - 8.91, 9.17 - 9.70) and 39.8 MeV (1966BA13: to ¹⁴N*(0, 2.31, 3.95, 7.03, 9.17, 10.43) and to a state at E_x = 13.72 ± 0.04 MeV). See also (1965SE01).

55. ¹⁶O(n, t)¹⁴N Q_m = -14.479

Not reported.

56. ¹⁶O(p, pd)¹⁴N Q_m = -20.736

See (1964BA1C).

57. ¹⁶O(p, ³He)¹⁴N Q_m = -15.243

At E_p = 40 MeV, angular distributions have been measured for the ³He particles corresponding to ¹⁴N*(0, 2.31, 3.95) (1966BR1X, 1966HO1F). The excitation of ¹⁴N*(7.03, 9.17) is also reported (1965PE17). At E_p = 43.7 MeV, a comparison has been made between the angular distributions of the ³He particles to ¹⁴N*(2.31) and the tritons (from the ¹⁶O(p, t)¹⁴O reaction) to ¹⁴O_g.s.. As would be expected from charge independence, the shape of the distributions and the cross sections are approximately the same to the two analog states: σ(p, t)/σ(p, ³He) = 1.12/1 (1964CE02).

58. ¹⁶O(d, α)¹⁴N Q_m = 3.111
Q₀ = 3.110 ± 0.006 (1964MA57).

Angular distribution of α-particles have been measured at many energies: see Table 14.25 (in PDF or PS). See also (1959FI30).

Alpha particle groups have been seen corresponding to most known states of ¹⁴N with E_x ≤ 11.51 MeV (in some cases, the identification of the groups is inconclusive), with the exception of previously reported states at E_x = 6.05, 6.70, 7.40 and 7.60 MeV (1968JO07: E_d = 5 to 9 MeV). See also (1965IS04). The yield of the isospin-forbidden α₁ group [to ¹⁴N*(2.31)] has been studied for E_d = 3 to 15 MeV. The intensity of the α₁ group, relative to the α₀ and α₂ groups [to the T = 0 states of ¹⁴N*(0, 3.95)] depends on the deuteron energy and on the angle of observation [the isospin impurity in the compound nucleus is a function of the excitation energy in ¹⁸F and of J] (1969JO09). Studies of the α₁ yield have also been conducted for E_d = 5.5 to 7.5 MeV (1956BR36) and 6.8 to 8.9 MeV (1958DA16). For further discussions, see (1963CE02, 1966BR1G, 1968NO1C, 1969NO1B, 1969NO1C). See also (1960HU10, 1961PE09, 1961YA08, 1963JA03, 1963YA1B) and ¹⁸F in (1972AJ02).

Preliminary results on the absolute cross sections of this reaction and its inverse [¹⁴N(α, d)¹⁶O] are in agreement, to ± 0.56%, with the principle of detailed balance (1967TH1E, 1968TH1J, 1969PL1C).

See also (1961TE02, 1963DO1B, 1963VA1E, 1964RI1C, 1966BE1E, 1966JA05, 1966KL1E, 1968KO24), (1960EL1E, 1961BA1J, 1961JA1H, 1964HO1E, 1966ME1E, 1967JO1H; theor.) and (1959AJ76).

59. ¹⁶O(α, ⁶Li)¹⁴N Q_m = -19.264

See (1965PE17).

60. ¹⁶O(¹⁰B, 3α)¹⁴N Q_m = -2.822

See (1965SH10, 1965SH14).

61. ¹⁷O(p, α)¹⁴N Q_m = 1.193

See ¹⁸F in (1972AJ02).

62. ¹⁹F(d, ⁷Li)¹⁴N Q_m = -6.121

See (1967DE03).

63. ²⁰Ne(d, 2α)¹⁴N Q_m = -1.619

See (1966KU1D).