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GENERAL: See also Table 19.3 [Table of Energy Levels] (in PDF or PS).

Theory: See (1955EL1A, 1955EL1B, 1955RE1D, 1955RE1E, 1956BA1J, 1956PA23, 1957PA1C, 1957RA1C, 1958AB1A, 1958KU1C, 1958RE1B).

1. 9Be(14N, α)19F

Qm = 13.263

See (1958GO71).

2. 15N(α, γ)19F

Qm = 3.993

Three resonances are observed (1957PR1A): see Table 19.4 [Resonances in ¹⁵N(α, γ)¹⁹F] (in PDF or PS). The γ-transition strengths indicate that all three yield dipole or E2 radiation. The indicated assignments are derived from branching ratios and angular distributions. Nether the 1.34 or the 2.8 MeV level may have J = 1/2 (1957PR1A).

3. 15N(α, α)15N

Eb = 3.993

Differential cross sections for elastic scattering at several angles have been measured for E_α = 1.7 to 5.4 MeV. Over twenty resonances have been observed: below E_x = 7 MeV the levels are narrow (≈ 10 keV); above this energy they are much broader (1958SM05: see (1958BU12)).

4. 16O(t, n)18F

Qm = 1.280

Eb = 11.693

The excitation function has been measured for E_t = 0.68 to 2.13 MeV; at the latter energy the cross section is 100 ± 20 mb (1955JA1A). See also (1950HO80).

5. 16O(α, p)19F

Qm = -8.119

At E_α = 20.6 MeV, proton groups are observed corresponding to excited states at 1.36 ± 0.05, 2.67 ± 0.05 and 3.92 ± 0.05 MeV (1951BU1E).

6. 17O(d, n)18F

Qm = 3.392

Eb = 13.806

See (1955BU1C) and (1950HO80).

7. 17O(d, p)18O

Qm = 5.842

Eb = 13.806

See ¹⁸O.

8. 17O(d, α)15N

Qm = 9.812

Eb = 13.806

See ¹⁵N.

9. 17O(t, n)19F

Qm = 7.548

Not reported.

10. 17O(3He, p)19F

Qm = 8.313

Not reported.

11. 17O(α, d)19F

Qm = -10.038

Not reported.

12. 18O(p, γ)19F

Qm = 7.964

Resonances for capture radiation observed for E_p = 0.3 to 2.6 MeV are displayed in Table 19.5 [Resonances in ¹⁸O(p, γ)¹⁹F, ¹⁸O(p, n)¹⁸F and ¹⁸O(p, α)¹⁵N] (in PDF or PS) (1955BU1D, 1955HU1D, 1956HI35). The 9.07 MeV level (E_p = 1.169 MeV) decays preferentially through the 2.8 MeV level. Its small width and the absence of α-decay may indicate a T = 3/2 character; the position is close to that expected for the analogue of the 1.47 MeV state of ¹⁹O (1955BU1D).

13. 18O(p, n)18F

Qm = -2.450

Eb = 7.964

Observed resonances in the neutron yield are listed in Table 19.5 [Resonances in ¹⁸O(p, γ)¹⁹F, ¹⁸O(p, n)¹⁸F and ¹⁸O(p, α)¹⁵N] (in PDF or PS) (1950RI59, 1951BL1A, 1956HI35 , 1956MA18, 1956NA1B). The relative weakness of (p, α) at E_p = 3.8 MeV suggests T = 3/2 for ¹⁹F*(11.5) (1957SZ1A). See also (1956TS1A).

14. 18O(p, p)18O

Eb = 7.964

See ¹⁸O.

15. 18O(p, d)17O

Qm = -5.842

Eb = 7.964

See (1956TS1A).

16. 18O(p, α)15N

Qm = 3.970

Eb = 7.964

Observed resonances are exhibited in Table 19.5 [Resonances in ¹⁸O(p, γ)¹⁹F, ¹⁸O(p, n)¹⁸F and ¹⁸O(p, α)¹⁵N] (in PDF or PS) (1951SE1C, 1953CO1F, 1956HI35 , 1957SZ1A). The sharp resonances at E_p = 633 and 846 keV are superposed on what may be one or more broad resonances: see (1953CO1F).

17. 18O(d, n)19F

Qm = 5.737

Neutron groups corresponding to 12 levels of ¹⁹F are reported by (1953SE1B). Two thresholds for slow neutron production are observed (1956HA1A): see Table 19.6 [Thresholds in the ¹⁸O(d, n)¹⁹F reaction] (in PDF or PS). Both are quite sharp, suggesting s-wave neutron emission; the lower is probably formed by s-wave deuterons, J = 1/2⁺, 3/2⁺ (1956HA1A). Seven thresholds for γ-ray production are reported. Of these one, at E_d = 1.85 MeV (¹⁹F*(7.40)), dose not appear in ¹⁵N(α, α)¹⁵N; it is suggested that this may be the first T = 3/2 level of ¹⁹F. Gamma-spectra are reported for several levels (1958BU12, 1959BU81).

18. 18O(3He, d)19F

Qm = 2.470

Not reported.

19. 18O(α, t)19F

Qm = -11.849

Not reported.

20. 19O(β-)19F

Qm = 4.789

The decay branches 30 ± 10 % to the 198 keV state (E_β = 4.5 ± 0.3 MeV) and 70% to a state at 1.57 MeV (E_β = 2.9 ± 0.3 MeV) (1947BL33, 1954JO21). With a half-life of 29 sec (see (1954AH1C, 1954MI89, 1958ST50)), log ft = 5.55 and 4.33, respectively (1951FE1A). Gamma rays of energy γ₁ = 1366 ± 8 keV, γ₂ = 199.6 ± 1.5 keV, and γ₃ = 111.5 ± 1.5 keV with relative intensities 0.67 : 1.00 : 0.04 are reported, as is the transition, γ₄, from the 1570 keV level to the 0.110 keV level. The γ₁-γ₂ coincidences indicate that γ₁ arises from the transition 1570 → 197: see Fig. 42 (Gamma-ray transitions in ¹⁹F). The transition 197 → 110 has an intensity < 0.5% and the transitions 1570 → 0 and 1570 → 1350 are ≤ 3 and ≤ 4%, respectively. The mean lifetime of the 197 keV state is (1.0 ± 0.2) × 10^-7 sec (1954JO21), (1.25 ± 0.025) × 10^-7 sec (1956JO35) while that of the 110 keV state is << 10^-6 sec (compare ¹⁹F(p, p')¹⁹F*) (1954JO21). The magnetic moment of the 197 keV state is 3.50 ± 0.24 nuclear magnetons (1956PH30) (compare ¹⁹F(p, p')¹⁹F*). Lower limits on log ft for β transitions to the ground state and those at 110 and 1350 keV are 6.5, 7.3, and 5.3 (1954JO21).

The present observations, together with Coulomb excitation data (¹⁹F(α, α')¹⁹F*) require J = 1/2^- and 5/2⁺ for the 110 keV and 197 keV levels (see also ¹⁹F(p, p')¹⁹F*). The assignment J = 3/2⁺ for the 1570 keV state is obtained from the ¹⁹O beta decay, from the γ₁-γ₂ angular correlation, and a study of γ₄. If the beta transitions to the 1570 and 197 keV states are allowed and that to the ground state is forbidden, it follows that ¹⁹O has J = 5/2⁺ (1954JO21). See also (1956TO1B) and (1957RA1C, 1958RE1B; theor.).

21. 19F(γ, n)18F

Qm = -10.414

Discontinuities in the activation curve are reported at 70 ± 20 keV above threshold (1958BE74) and at 10.6, 11.0, 11.2, 11.5, 11.9, 12.2, and 15.3 MeV (1954GO39, 1954TA1B). The "giant" resonance appears at E_γ = 22.2 MeV, Γ = 5.6 MeV (1954FE16: see also (1952HO1B)). See also (1955AJ61).

22. 19F(γ, 2n)17F

Qm = -19.582

See (1952HO1B, 1958MA1L).

23. 19F(γ, p)18O

Qm = -7.964

See (1955LA1E, 1956WH1A, 1958JO1C).

24. 19F(p, d)18F

Qm = -8.187

At E_p = 18 MeV, the ground-state reduced width, θ²_n = 0.009 (1956RE04).

25. 19F(p, α)16O

Qm = 8.119

At E_p = 18.5 MeV, the angular distribution shows strong maxima and minima, indicative of triton pickup. The triton reduced width for ¹⁹F(0) is θ² = 0.1 - 0.15 (1956LI37).

26. 19F(n, n')19F*

At E_n = 540 keV, only two γ-ray lines appear, at E_γ = 111 ± 1.5 keV and 196 ± 2 keV. At E_n = 1.50 MeV, a threshold occurs for a further line, at E_γ = 1.24 MeV. At E_n = 1.6 MeV, lines with E_γ = 1.24, 1.36, and 1.47 MeV are observed: see Table 19.7 [Gamma rays from ¹⁹F(n, n'γ)¹⁹F] (in PDF or PS) and Fig. 42 (Gamma-ray transitions in ¹⁹F). The level assignments indicated in the table derive from coincidence studies. Upper limits on other γ-lines are about 10% (1956FR1D). At E_n = 3.7 MeV, a line at E_γ = 2.594 MeV is observed, attributed to a level at 2.791 MeV (cascade to ¹⁹F*(0.197)). The excitation function suggests J = 7/2 or 9/2 (1957FR57). (1956VA29) find the threshold for 1.37 MeV radiation at E_n = 1.55 ± 0.2 MeV. (1956DA23) reports the relative intensity of the cascade ¹⁹F*(0.197 → 0.111) as < 6 × 10^-3 of (0.197 → 0). See also (1955FR1B, 1955GR18, 1955VA1B, 1956CR31).

27. 19F(p, p')19F*

Observed proton groups are listed in Table 19.8 [Proton groups from ¹⁹F(p, p')¹⁹F*] (in PDF or PS) (1952AR29, 1954PE1C, 1955GO1F, 1956SQ1A, 1957HO1J, 1957YO04). At E_p = 7.3 MeV, no other groups appear for E_x < 4.05 MeV with intensity > 2% of the Q = -1.558 MeV group (1956SQ1A).

The energy of the first excited state is given as 109.87 ± 0.04 keV from the energy of the γ-decay (1958CH34: see also Table III (19) in (1955AJ61)). The lifetime of the state is (1.0 ± 0.25) × 10^-9 sec (1954TH41). The internal conversion coefficient indicates E1 and therefore J = 1/2^- or 3/2^- for the 0.11 MeV state (1955MI1B). Since the cascade transition from the 0.2 (J = 5/2⁺) to the 0.1 MeV state is not observed, J = 1/2^- is indicated (1954SH1B, 1955BA94).

The lifetime of the 198 keV state is 0.8 × 10^-7 sec (1954TH41), (1.23 ± 0.07) × 10^-7 sec (1955FI38, 1956LE1F): see also ¹⁹O(β^-)¹⁹F. The lifetime requires E2 or faster radiation; the internal conversion coefficient indicates E2 (1955MI1B). Angular distributions at various J = 2^- resonances in ²⁰Ne* confirm the assignment J^π = 5/2⁺ for ¹⁹F*(0.197) (1954CH27, 1954PE1C, 1954SH1B, 1955BA94). The Coulomb excitation also requires an E2 transition (1956TE1A). The magnetic moment is 3.70 ± 0.45 n.m. (1955LE1C, 1956LE1F, 1956LE22), 3.0 ± 0.7 n.m. (1956SU1C), 4.5 ± 1.0 n.m. (1955TR1C, 1956TR1A), 3.5 ± 0.5 n.m. (1958MA38): the value predicted by (1955EL1B) is 3.3 n.m.; compare ¹⁹O(β^-)¹⁹F. The static electric quadrupole moment is 0.13 × 10^-24 cm² (1958SU58). See also (1956BA1J, 1957RA1C, 1957TR1A, 1957TR1B).

The γ-decay of higher excited states has been studied by (1956TO1B: E_p = 2.4 to 4.1 MeV): see Fig. 42 (Gamma-ray transitions in ¹⁹F). Gamma rays with E_γ = 1.238 ± 0.010, 1.350 ± 0.010 and 1.449 ± 0.010 MeV are observed in addition to the two low energy γ's. The 1.24 and 1.35 MeV γ-rays are in prompt coincidence with 0.11 MeV radiation, indicating cascade decay of states at 1.342 ± 0.010 MeV and 1.452 ± 0.010 MeV through the 0.11 MeV state. A (1.354 ± 0.010) MeV γ-ray is found to be in delayed coincidence with 197 keV radiation, indicating the cascade decay of a level at 1.551 ± 0.010 MeV through the J = 5/2⁺ second excited state. The 1.34 MeV state does not appear to decay to the 0.198 MeV state (< 8%); it decays almost entirely to the J = 1/2^- first excited state. This observation suggests J = 1/2 or 3/2, with J = 5/2 not excluded; the observed anisotropy excludes J = 1/2. Similarly, the γ-decay of the 1.46 MeV state suggests J = 1/2 or 3/2. The assignment J = 3/2⁺ for ¹⁹F*(1.56) follows from ¹⁹O(β^-)¹⁹F (1956TO1B). (1958RA26) find gamma-ray energies of 1236 ± 10, 1358 ± 8 and 1460 ± 30 keV, not corrected for Doppler shift. Relative intensities for E_p = 3.2 to 4.7 MeV are given. See also (1958RA15) and ¹⁹F(n, n')¹⁹F*.

For elastic and inelastic scattering at high energies, see (1956BU95, 1956DA03, 1956KL55, 1956ST30, 1957GI14, 1958TY47).

28. 19F(d, d')19F*

At E_d = 8.9 MeV, deuteron groups are observed to states at 1.60 ± 0.02 and 2.83 ± 0.02 MeV (1956EL1A). See also (1954TH1B).

29. 19F(α, α')19F*

Gamma radiation of energy 110 keV and 197 keV (See Table III (19) of (1955AJ61)) is observed for E_α = 0.6 to 3.5 MeV. The shape of the rise, the absolute cross sections at low energies, and the γ-ray angular distributions agree well with E1 and E2 Coulomb excitation, respectively, of the first two excited states (see (1954HE22, 1954JO1G, 1954SH1B, 1954TE1B, 1956TE1A)).

30. 19F(14N, 14N'γ)19F

At E(¹⁴N) = 15.6 MeV, γ-rays are observed from the Coulomb excitation of the first two excited states (1956AL1D, 1956AL36, 1956AL55).

31. 19Ne(β+)19F

Qm = 3.256

See ¹⁹Ne.

32. 20Ne(n, d)19F

Qm = -10.646

Not reported.

33. 20Ne(d, 3He)19F

Qm = -7.379

Not reported.

34. 20Ne(t, α)19F

Qm = 6.940

Not reported.

35. 21Ne(n, t)19F

Qm = -11.145

Not reported.

36. 21Ne(p, 3He)19F

Qm = -11.910

Not reported.

37. 21Ne(d, α)19F

Qm = 6.441

At E_d = 2.1 MeV, α-particle groups are observed to ¹⁹F*(0, 113 ± 8, and 192 ± 12 keV) (1952MI54).

38. 22Ne(p, α)19F

Qm = -1.698

Not reported.