A=20F (1983AJ01)

The half-life of ²⁰F is 11.00 ± 0.02 sec: see (1978AJ03). See also (1975SA1D, 1978CA02). ²⁰F decays principally to ²⁰Ne*(1.63): see ²⁰Ne, reaction 42.

2. ¹²C(⁹Be, p)²⁰F Q_m = 4.0761

At E(⁹Be) = 12 to 27 MeV angular distributions are reported (1979JA22, 1981JA09: p₀, p_1+2+3+4). See also (1978AJ03).

3. ¹³C(⁷Li, ⁷Li)¹³C E_b = 18.050

See (1976PO02, 1978DR07) and ¹³C in (1981AJ01). For fusion cross sections see (1981DEZE, 1981DEZW).

4. ¹³C(⁹Be, d)²⁰F Q_m = 1.3543

At E(¹³C) = 27.9 MeV angular distributions are reported by (1980BO21: d₀, d_1+2+3+4).

5. ¹³C(¹¹B, α)²⁰F Q_m = 9.3851

The upper of the two states at 2.97 MeV has an excitation energy of 2968 ± 1.5 keV and γ branching ratios of 61 ± 4 and 39 ± 4 %, respectively, to ²⁰F*(1.97, 0.82) [J^π = (3^-), 4⁺]: this is consistent with J^π = (4^-) for ²⁰F*(2.968) (1978LE19).

6. ¹⁴N(⁷Li, p)²⁰F Q_m = 12.054

The ²⁰F states observed in this reaction at E(⁷Li) = 16 MeV are displayed in Table 20.7 (in PDF or PS). The cross sections for forming states of known J^π are proportional to 2J_f + 1 with slopes which are different for the even- and the odd-parity states. Extrapolation of these relationships to states of unknown J^π leads to the assignments shown in Table 20.6 (in PDF or PS) (1977FO11).

7. ¹⁶O(⁷Li, ³He)²⁰F Q_m = -4.743

Angular distributions have been measured at E(⁷Li) = 24 MeV for the ³He groups corresponding to the states shown in Table 20.7 (in PDF or PS). It is suggested that the states at E_x = 4.20, 4.52, 4.58 and 5.41 MeV have high spin and (sd)⁴ configurations (1978FO14).

8.^† ¹⁷O(t, p)¹⁹O Q_m = 3.520 E_b = 14.157
^†(Additional reactions on which no new work is reported are listed in (1978AJ03).)

See ¹⁹O.

9. ¹⁷O(¹³C, ¹⁰B)²⁰F Q_m = -9.719

See (1979GO17).

10. (a) ¹⁸O(d, n)¹⁹F Q_m = 5.7685 E_b = 12.3699
(b) ¹⁸O(d, p)¹⁹O Q_m = 1.732

Vector analyzing power measurements [reaction (b)] have been carried out at E_d-bar = 10 MeV (1979ST21; p₀, p₂, p₃, p₄) and at 14 MeV: see (1978AJ03). See also (1981NE1B; theor.). See also ¹⁹O. For reaction (a) see ¹⁹F.

11. ¹⁸O(d, d)¹⁸O E_b = 12.3699

VAP measurements involving the elastic group have been carried out at E_d-bar = 10 MeV (1979ST21) and at 14.8 MeV: see (1978AJ03).

12. (a) ¹⁸O(d, ³He)¹⁷N Q_m = -10.449 E_b = 12.3699
(b) ¹⁸O(d, α)¹⁶N Q_m = 4.246

VAP measurements are reported at E_d-bar = 52 MeV for reaction (a) (1981MA14: to ¹⁷N*(0, 1.37, 1.85, 2.53, 5.51, 6.99) and (b) (1982MA25: to ¹⁶N*(0, 0.30, 3.36, 3.96, 4.32, 6.17). TAP measurements are reported to reaction (b) at E_d-bar = 8.5 to 11.3 MeV (1978BA43). For excitation functions see (1972AJ02). See also ¹⁶N, ¹⁷N in (1982AJ01) and (1979SE04).

12. ¹⁸O(t, n)²⁰F Q_m = 6.1126

See (1978AJ03).

13. ¹⁸O(³He, p)²⁰F Q_m = 6.8764

States of ²⁰F observed in this reaction are displayed in Table 20.7 (in PDF or PS). For a complete listing of the references see (1978AJ03).

14. ¹⁹F(n, γ)²⁰F Q_m = 6.6012

The thermal capture cross section is 9.8 ± 0.7 mb (1974SH1E). A number of resonances have been observed: see Table 20.8 (in PDF or PS). See also (1981MUZQ). The primary γ-rays resulting from capture at thermal energies (²⁰F*(6.60); J^π = 0⁺, 1⁺) and at E_n = 27, 44 and 49 keV (²⁰F*(6.63, 6.643, 6.647); J^π = 2^-, (3, 4) and 1^-) have been studied by several groups: see (1972AJ02) and Table 20.9 (in PDF or PS) here. It appears that the thermal capture [²⁰F*(6.60)] is dominated by two intense transitions (probably E1) to ²⁰F*(5.94, 6.02) [thus J^π = 1^-, 2^-]. If the ground-state transition is mainly M1, these two E1 transitions are (in terms of W.u.) about 150 times stronger than the M1 transition (1968SP01). It appears also that at ²⁰F*(6.63, 6.64, 6.65) [J^π = 2^-, (3, 4) and 1^-] the E1 transitions to the ground state are very weak, even though other E1 transitions in the decay of these two states have approximately normal strengths (1967BE36, 1974KE18). The strongest transitions from the 27 keV resonance appear to be M1. On the basis of the J^π of the final states involved in the decay of the 44 keV resonance J = 3 or 4, assuming dipole transitions (1974KE18). Branching ratios for other ²⁰F states involved in this reaction are shown in Table 20.4 (in PDF or PS).

Table 20.10 (in PDF or PS) displays excitation energies for ²⁰F states involved in cascade and in primary γ-transitions.

15. ¹⁹F(n, n)¹⁹F E_b = 6.6012

The scattering amplitude (bound) a = 5.654 ± 0.010 fm, σ_free = 3.641 ± 0.010 b (1979KO26). See also (1981MUZQ).

The total cross section has been measured for E_n = 0.5 to 29.1 MeV: see (1978AJ03). Observed resonances are displayed in Table 20.11 (in PDF or PS). See also ¹⁹F.

16. ¹⁹F(n, n')¹⁹F* E_b = 6.6012

Observed resonances in the excitation functions involving ¹⁹F*(0.11, 1.5 [u]) are displayed in Table 20.12 (in PDF or PS). See also (1978CO18, 1980CO1U) and (1978AJ03).

17. ¹⁹F(n, 2n)¹⁸F Q_m = -10.4313 E_b = 6.6012

Cross sections have been measured for E_n = 10 to 37 MeV [see (1978AJ03)] and at E_n = 14.7 - 19.0 MeV (1978RY02) and 16.2 - 21.8 MeV (1978CO18, 1980CO1U). See also (1979HA60).

18. ¹⁹F(n, p)¹⁹O Q_m = -4.036 E_b = 6.6012

The differential cross section at 92° for production of the 96 keV γ-ray has been studied by (1976MO13: E_n = 4.0 to 18.6 MeV): the cross section increases sharply at E_n = 6 MeV and then gradually decreases beyond E_n = 12 MeV. Cross sections have also been measured for E_n = 12.6 to 21 MeV: see (1972AJ02) and the summary in (1976GAYV). See also (1978SM1E, 1979BR08, 1979HA60).

19. (a) ¹⁹F(n, d)¹⁸O Q_m = -5.7688 E_b = 6.6012
(b) ¹⁹F(n, t)¹⁷O Q_m = -7.556

For reaction (a) see (1978CO18, 1980CO1U). For reaction (b) see (1978QA01). For both see also (1978AJ03).

20. ¹⁹F(n, α)¹⁶N Q_m = -1.522 E_b = 6.6012

Reported resonances are shown in Table 20.13 (in PDF or PS): see graph in (1976GAYV). See also (1978SM1E, 1979BR08).

21. ¹⁹F(p, π⁺)²⁰F Q_m = -133.748

Cross sections at 5.3 and 10.4 MeV above threshold are reported by (1979MA39).

22. ¹⁹F(d, p)²⁰F Q_m = 4.3765

States of ²⁰F observed in this reaction are displayed in Table 20.14 (in PDF or PS). Angular distributions have been measured at E_d = 0.6 to 16 MeV [see (1978AJ03)] and at 12 MeV (1977MO16). See (1978AJ03) for a discussion of the earlier work. See also (1980HU1D, 1980HU1J).

23. ¹⁹F(¹³C, ¹²C)²⁰F Q_m = 1.6548

See (1978AJ03).

24. ²⁰O(β^-)²⁰F Q_m = 3.816

See ²⁰O.

25. ²⁰Ne(π^-, γ)²⁰F Q_m = 132.541

The branching ratio to ²⁰F*(1.06) [J^π = 1⁺] is compared to the analogous M1 decay width ²⁰Ne*(11.24) [J^π = 1⁺] → ²⁰Ne_g.s.. The M1 amplitude contains (47 ± 16)% spin flip, in agreement with shell-model calculations. The population of ²⁰F*(0, 1.31, 1.84) [J^π = 2⁺, 2^-, 2^-] is also reported (1981MA04). See also (1979TR1B, 1982RI1B).

26. ²¹Ne(d, ³He)²⁰F Q_m = -7.511

The ²⁰F states observed at E_d = 26 MeV in this reaction and analog [T = 1] states observed in ²⁰Ne in the (d, t) reaction are displayed in Table 20.15 (in PDF or PS). The spectroscopic factors of analog states are consistent to within 20% for states excited by a single l-transfer (1974MI13).

27. ²²Ne(p, ³He)²⁰F Q_m = -15.6513

At E_p = 43.7 to 45.0 MeV analog states have been studied in ²⁰F and ²⁰Ne [the latter via ²²Ne(p, t)²⁰Ne]. Angular distributions for the ³He ions and the tritons corresponding to the first T = 2 states (J^π = 0⁺) [²⁰Ne*(16.722 ± 0.025) and ²⁰F*(6.513 ± 0.033)] have been compared. There is indication also for the excitation of the 2⁺; T = 2 states [at E_x = 8.05 MeV in ²⁰F and at 18.5 MeV in ²⁰Ne (estimated errors ± 0.1 MeV)] (1964CE05, 1969HA38).

28. ²²Ne(d, α)²⁰F Q_m = 2.7019

Angular distributions have been obtained at E_d = 10 MeV to all ²⁰F states with E_x < 4.4 MeV: they are generally featureless. Observed states of ²⁰F are displayed in Table 20.16 (in PDF or PS). See also (1978AJ03).

29. ²³Na(n, α)²⁰F Q_m = -3.866

See (1978AJ03).