A=18F (1983AJ01)

TUNL Nuclear Data
Evaluation Home Page

Information on mass
chains and nuclides

3 4

5 6

7 8

9 10

11 12

13 14

15 16

17 18

19 20

Group Info

Publications

HTML

General Tables

Level Diagrams

Tables of EL's

NSR Key# Retrieval

ENSDF

Excitation Functions

Thermal N Capt.

G.S. Decays

Half-Lives Table

TUNL Dissertations

NuDat at BNL

Useful Links

Citation Examples

Home

Sitemap

Directory

Email Us

WWW TUNL

¹⁸F (1983AJ01)

(See Energy Level Diagrams for ¹⁸F)

GENERAL: See also (1978AJ03) and Table 18.11 [Table of Energy Levels] (in PDF or PS).

Shell model: (1977AN1P, 1977GR16, 1977SO11, 1978CO08, 1978DA1N, 1978MA2H, 1979BU12, 1979DA15, 1980GO01, 1980KU05, 1980MA18, 1981EL1D, 1981ER03, 1981GR06, 1982KI02).

Cluster, collective and deformed models: (1977BU22, 1978BU03, 1978PI1E, 1978SA15, 1978TA1A, 1979BU12, 1979SA31, 1980RO19, 1981CH24).

Electromagnetic transitions: (1976MC1G, 1977BU22, 1977HA1Z, 1977HE1L, 1978BU03, 1978DE1K, 1978SA15, 1979SA31, 1980KO1L, 1980KU05, 1981CH24).

Special states: (1977AN1P, 1977GR16, 1977HE18, 1977SH18, 1978AN1P, 1978BU03, 1978EN1D, 1978ER1C, 1978KO1W, 1978KR1G, 1978MA2H, 1978PI1E, 1978SA15, 1978TA1A, 1979BA35, 1979BU12, 1979DA15, 1979SA31, 1979WI1Q, 1979ZA07, 1980BR21, 1980GO01, 1980HA41, 1980MA18, 1980RO19, 1980SH1K, 1981AD1E, 1981AR1D, 1981BI03, 1981EL1D, 1981ER03, 1981SO03, 1982KI02, 1982NA03).

Astrophysical questions: (1977SI1D, 1979WO07, 1981WE1F).

Applied topics: (1977FI13, 1978FR1R, 1978WI1F, 1978WO1C, 1979BA52, 1979KA07, 1979WI1G, 1980LA1K, 1980YA08).

Complex reactions involving ¹⁸F: (1977AS03, 1977SC1G, 1977YA1B, 1978SH18, 1979BO22, 1979VI09, 1980EV1A, 1980WI1K, 1980WI1L, 1980YA08, 1981GR08).

Pion induced capture and reactions: (1977ST27, 1978SP07, 1981NI03).

Other topics: (1977AN1P, 1977GR16, 1977SH18, 1977SO11, 1978AN1P, 1978CO08, 1978DE1K, 1978EN1D, 1978GO1U, 1978JO1C, 1978KR1G, 1978MA2H, 1978SH1B, 1979BA35, 1979BE2L, 1979CO09, 1979DE18, 1979GO1W, 1979HW01, 1979KU04, 1979WI1Q, 1980BR21, 1980DE1F, 1980GO01, 1980TA1L, 1981AR1D, 1981BI03, 1981CH24, 1981EL1D, 1981ER03, 1981SO03, 1982FI1C, 1982KI02, 1982NA03).

Ground and 1.12 MeV states of ¹⁸F: (1976MC1G, 1977HA1Z, 1978ZA1D, 1980MA18, 1981AR1D).

μ_1.12 = +2.86 ± 0.03 nm (1978LEZA);

Q_1.12 = 0.13 ± 0.03 b (1974MI21); see also (1978LEZA).

1. ¹⁸F(β⁺)¹⁸O

Q_m = 1.6555

The positron decay is entirely to the ground state of ¹⁸O [J^π = 0⁺, T = 1]; the half-life is 109.77 ± 0.05 min [see Table 18.11 (in PDF or PS) in (1972AJ02)]; log ft = 3.554. The fact that the β⁺ transition to ¹⁸O_g.s. is allowed indicates J^π = 1⁺ for ¹⁸F_g.s.. The ratio ε_K/β⁺ = 0.030 ± 0.002; see (1978AJ03). See also (1976BE1E, 1981BE2N, 1982PI1B) and (1980AN31; theor.).

2. (a) ¹²C(⁶Li, n)¹⁷F Q_m = 4.064 E_b = 13.215
(b) ¹²C(⁶Li, p)¹⁷O Q_m = 7.608
(c) ¹²C(⁶Li, d)¹⁶O Q_m = 5.6885
(d) ¹²C(⁶Li, t)¹⁵O Q_m = -3.718
(e) ¹²C(⁶Li, α)¹⁴N Q_m = 8.7989
(f) ¹²C(⁶Li, ⁶Li)¹²C

Cross-section measurements have been carried out in the range E(⁶Li) = 1.9 to 36 MeV: see (1978AJ03) and (1976PO02; 4 to 13 MeV; ⁶Li elastic), (1978SO01; 9 to 14 MeV and 20 MeV; α₀, α₁, α₂), (1980FU06; 20 to 36 MeV; ⁶Li to ¹²C*(0, 4.43)) and (1978CU03; 20 to 34 MeV; d to ¹⁶O*(0, 6.13, 6.92, 7.12, 8.87, 10.36, 11.09, 16.3)).

The cross section for the isospin-forbidden α₁ group [to ¹⁴N*(2.31), 0⁺, T = 1] is 1 to 2% of the cross section to the allowed α₀ and α₂ groups for E(⁶Li) = 3.2 to 6 MeV (1981SC13) while for 9 to 14 MeV it varies from 0.4 to 1.8% (1978SO01). At 20 MeV, the α₁ yield is 0.02% of the allowed yield (1978SO01). Structures are reported at E(⁶Li) = 11.0 and 13.0 MeV in the α₀ yield, at 11.5 and (13.0) MeV in the α₁ yield and at ≈ 11.7 and 12.8 MeV in the α₂ yield (1978SO01), while (1981SC13) report a resonance in the α₁ yield at E(⁶Li) = 4.2 MeV: E_x = 15.99 ± 0.02 MeV, Γ_c.m. = 290 ± 30 keV, J^π = 2⁺ (one-level BW fit). It is suggested that this resonance is due to 2⁺ states with T = 0 and T = 1 which are unresolved (1981SC13). The excitation functions for the ⁶Li ions to ¹²C*(0, 4.43) shows a single isolated structure at E(⁶Li) = 22.8 MeV, in the range 20 - 36 MeV, with Γ ≈ 0.8 MeV. It is unlikely to be due to an isolated state in ¹⁸F (1980FU06). At E(pol. ⁶Li) = 20 MeV analyzing power measurements are reported for many deuteron and α groups and for elastically scattered ⁶Li ions (1978MA13, 1979MA1T). Breakup processes have been studied by (1980NE05), cross sections at very high energies by (1980SK1A), fusion by (1981DEZE, 1981DEZW). See also ¹⁶O, ¹⁷O in (1982AJ01), and ¹⁴N, ¹⁵N in (1981AJ01) and ¹²C in (1980AJ01).

For a discussion of the earlier work see (1978AJ03). See also (1979TU1B, 1981KR1K), (1978FI1E, 1978HO1C) and (1978ME1J, 1978ME20, 1978ME14, 1979BE59, 1979SU1F, 1981ME1E, 1981ME1F, 1981OS1D; theor.).

3. ¹²C(⁷Li, n)¹⁸F Q_m = 5.964

See (1972AJ02).

4. ¹²C(⁹Be, t)¹⁸F Q_m = -4.4744

Angular distributions are reported at E(⁹Be) = 12 to 27 MeV to ¹⁸F_g.s. and to the unresolved states at 1 MeV (1979JA22, 1981JA09).

5. (a) ¹²C(¹⁰B, α)¹⁸F Q_m = 8.754
(b) ¹²C(¹¹B, αn)¹⁸F Q_m = -2.701

See (1978AJ03). The work on reaction (b) displayed there has not been published.

6. ¹²C(¹²C, ⁶Li)¹⁸F Q_m = -14.960

See (1980KO02).

7. ¹³C(¹⁴N, ⁹Be)¹⁸F Q_m = -6.232

See (1978PI1E).

8. ¹⁴N(α, γ)¹⁸F Q_m = 4.4159

A number of resonances have been observed for E_α < 3 MeV: see Table 18.14 (in PDF or PS). Studies of these, principally by the Toronto and Queen's groups [see references in (1978AJ03) and (1977BE46, 1979KI12, 1980MA26)] in conjunction with work on ¹⁴N(α, α), ¹⁶O(³He, p), ¹⁷O(p, γ) and ¹⁷O(p, α) [see Tables 18.16 (in PDF or PS), 18.17 (in PDF or PS), 18.18 (in PDF or PS)] have led to the determination of branching ratios, mixing ratios and widths (Table 18.12 (in PDF or PS)), lifetimes (Table 18.13 (in PDF or PS)) and the E_x, J^π and K^π assignments for ¹⁸F states with E_x < 6.9 MeV. The reader is referred to the series of papers by the Toronto group for the most complete and definitive arguments on the parameters of the low-lying states of ¹⁸F.

The non-resonant S-factor for this reaction, S ≈ 0.7 MeV · b (1972CO1C). See also (1978TA1U; astrophys.).

9. ¹⁴N(α, n)¹⁷F Q_m = -4.7347 E_b = 4.4159

See (1978AJ03).

10. ¹⁴N(α, p)¹⁷O Q_m = -1.1908 E_b = 4.4159

Observed resonances are displayed in Table 18.14 (in PDF or PS). See also (1978AJ03).

11. ¹⁴N(α, α)¹⁴N E_b = 4.4159

Observed anomalies in the elastic scattering are exhibited in Table 18.14 (in PDF or PS). Resonances in the α₁ isospin-forbidden yield are displayed in Table 18.14 (in PDF or PS) of (1978AJ03). In the α₁ study, carried out for E_α = 7.6 - 16.9 MeV, a partial-wave analysis involving a method of removing ambiguities and parametrizing S-matrix elements gives the level parameters of 151 isospin mixed, natural-parity states in ¹⁸F with 10.4 < E_x < 17.5 MeV. Many of these states have also been reported in the ¹⁶O(d, α₁) reaction [Table 18.16 (in PDF or PS) of (1978AJ03)]. The agreement is best for low-lying 2⁺ or 4⁺ states, and is quite good for 3^- and 5^- states, while for high-J states the greater centrifugal barrier for ¹⁶O + d at the same E_x relatively suppresses high-J states in the ¹⁶O + d work. A study of the energy dependence of averaged intensities of the partial waves shows some indication that the lower partial waves reconserve isospin as E_x increases (1976CH24).

12. (a) ¹⁴N(α, 2α)¹⁰B Q_m = -11.6132 E_b = 4.4159
(b) ¹⁴N(α, ⁶Li)¹²C Q_m = -8.7989

The total cross section for formation of ¹⁰B and ⁶Li have been studied for E_α = 21 to 42 MeV by (1974JA11) who discuss the astrophysical importance of these processes. For spallation studies see (1979VI05, 1980RE1B, 1981GOZY). See also (1980BA2K; theor.).

13. ¹⁴N(⁶Li, d)¹⁸F Q_m = 2.942

Angular distributions have been measured for E(⁶Li) = 5.3 to 6 MeV: see (1978AJ03).

14. ¹⁴N(⁷Li, t)¹⁸F Q_m = 1.949

At E(⁷Li) = 15 MeV, triton groups are observed to the known T = 0 states with E_x < 7.4 MeV: the T = 1 states are not excited although such transitions are not forbidden in principle, suggesting a direct α-transfer mechanism. The transitions to ¹⁸F*(1.70, 2.53, 3.36, 4.23, 5.30, 6.57) account for more than one-half of the summed cross section at 15°. It is proposed that these states (which are only weakly excited in ¹⁶O(³He, p)¹⁸F and ¹⁷O(³He, d)¹⁸F) are predominantly of a 4p - 2h nature and are excited by the transfer of four nucleons into the (2s, 1d) shell (1968MI09). At E(⁷Li) = 36 MeV the K^π = 1⁺ band also appears to be selectively populated. States at E_x = 9.58 ± 0.02, 11.22 ± 0.03 and 14.18 ± 0.04 MeV are strongly populated. It is suggested that the first two are the 6⁺ and 7⁺ members of that band (1977CO09). [Angular distributions are reported for ¹⁸F*(1.70, 2.10, 2.52, 3.36, 4.40, 5.30, 6.57, 9.58, 11.22, 14.18).] See also (1979SA31; theor.).

15. (a) ¹⁴N(¹¹B, ⁷Li)¹⁸F Q_m = -4.249
(b) ¹⁴N(¹³C, ⁹Be)¹⁸F Q_m = -6.2320

These reactions have been studied at E(¹¹B) = 115 MeV and E(¹³C) = 105 MeV. Differential cross sections at three angles are reported for the transitions to ¹⁸F*(9.58, 10.57 ± 0.07, 11.2) in reaction (a) and to ¹⁸F*(5.30, 6.57, 9.58, 10.60 ± 0.08, 11.2) in reaction (b). In addition to these states ¹⁸F*(14.18) is strongly excited in both reactions, and transitions to ¹⁸F*(15.79 ± 0.10, 18.62 ± 0.12) are also reported (1979BR04).

16. ¹⁴N(¹⁶O, ¹²C)¹⁸F Q_m = -2.7461

See (1977VO08).

17. ¹⁵N(³He, γ)¹⁸F Q_m = 14.1603

Excitation functions have been measured for E(³He) = 2.5 to 16 MeV for the γ₀ and γ_1→4 yields. Resonances are observed corresponding to E_x = (19.00 ± 0.15) [γ_1→4], 20.1 ± 0.2 [γ₀, γ_1→4], 22.7 ± 0.2 [γ₀, γ_1→4] and (24.1 ± 0.2) MeV [γ_1→4], with Γ_c.m. = 0.5 ± 0.15, 1.6 ± 0.1, 1.2 ± 0.1 and 1.4 ± 0.3 MeV, respectively. The γ₀ yield is dominated by ¹⁸F*(20.1) (1981WA1R) [see for (2J + 1)Γ_³HeΓ_γ values]. It is suggested that the structures decaying by γ₀ have J^π = 2^- (and possibly T = 1) (1981WA1R, and J. Lowe, private communication).

18. ¹⁵N(³He, p)¹⁷O Q_m = 8.554 E_b = 14.1603

See ¹⁷O in (1982AJ01).

19. ¹⁵N(α, n)¹⁸F Q_m = -6.4175

See (1978AJ03).

20. ¹⁵N(⁶Li, t)¹⁸F Q_m = -1.634

At E(⁶Li) = 30 MeV preferential excitation of odd-parity states of ¹⁸F below E_x = 5 MeV is reported. Angular distributions of the tritons to ¹⁸F*(0, 0.94, 2.10, 4.40) [J^π = 1⁺, 3⁺, 2^-, 4^-] are all strongly forward peaked (1972LI24).

21. (a) ¹⁵N(¹¹B, ⁸Li)¹⁸F Q_m = -13.050
(b) ¹⁵N(¹²C, ⁹Be)¹⁸F Q_m = -12.1190

These reactions have been studied with E(¹¹B) = E(¹²C) = 115 MeV. Reaction (a) is dominated by the transitions to ¹⁸F*(1.12) [presumably the J^π = 5⁺ state, although the group is unresolved] and to ¹⁸F*(7.15, 9.45) [J^π = (7^-) and (6^-)]. In reaction (b) no single state is strongly preferentially populated (1979RA10, 1981GO11). Differential cross sections for ¹⁸F*(4.40, 6.10, 7.15, 9.45) [J^π = 4^-, (5^-), (7^-), (6^-)], fitted by FRDWBA, are discussed by (1981GO11). See also (1977FO1E).

22. ¹⁶O(d, γ)¹⁸F Q_m = 7.5263

The capture cross section rises from 0.1 μb at E_d = 0.4 MeV to 25 μb at 3.5 MeV: Γ_γ over this range is ≈ 2 eV. The results can be interpreted satisfactorily in terms of compound nucleus formation (1965OW01).

23. ¹⁶O(d, n)¹⁷F Q_m = -1.6243 E_b = 7.5263

Excitation functions have been measured for the n₀ and n₁ groups from threshold to 17 MeV: see (1978AJ03). Some structure is observed: that which is attributed to states of ¹⁸F is displayed in Table 18.15 (in PDF or PS). Polarization measurements are reported for E_d = 3 to 15 MeV: see (1978AJ03) and at E_d-bar = 5 to 15 MeV (1981LI23; pol. n₀₊₁). See also ¹⁷F in (1982AJ01), (1980HU1J, 1980HU1D) and (1981NO1B).

24. ¹⁶O(d, p)¹⁷O Q_m = 1.9197 E_b = 7.5263

Excitation functions and polarization studies have been reported for several proton groups for E_d = 0.3 to 17 MeV: see (1978AJ03) and (1978RO1M; E_d-bar = 14 to 17 MeV). Some of the maxima in the yield measurements are interpreted in terms of resonances: these are shown in Table 18.15 (in PDF or PS). See also ¹⁷O in (1982AJ01).

25. ¹⁶O(d, d)¹⁶O E_b = 7.5263

The yield of elastically scattered deuterons and elastic polarization measurements have been reported for E_d = 0.65 to 56 MeV: see (1978AJ03) and (1982AOZZ; E_d = 13.8 to 16.5 MeV), (1981FR1C; TAP; E_d-bar = 20 MeV), (1981CL1C; VAP; E_d-bar = 20.5 MeV; also to ¹⁶O*(6.13)), (1980MA10; VAP; E_d-bar = 52 MeV), (1980HA14; VAP; E_d-bar = 56 MeV). For total cross sections at high energies see (1979DE31). See also ¹⁶O in (1982AJ01), (1978RO1M) and (1979NI1B, 1980AY01, 1981AO01, 1982YA1A; theor.).

26. (a) ¹⁶O(d, t)¹⁵O Q_m = -9.4065 E_b = 7.5263
(b) ¹⁶O(d, ³He)¹⁵N Q_m = -6.6340

Vector analyzing powers have been studied at E_d-bar = 29 MeV (1978CO13: to ¹⁵N*(0, 6.32) and ¹⁵O*(0, 6.18)) and 52 MeV (1977BE70: to ¹⁵N*(0, 6.32, 9.94, 10.71)). See also (1978AJ03) and (1981MA14).

27. ¹⁶O(d, α)¹⁴N Q_m = 3.1104 E_b = 7.5263

The yields of various groups of α-particles have been measured for E_d ≤ 20 MeV: see (1978AJ03) and (1979MA2Q; 0.65 to 1.1 MeV; α₀), (1978RI05; 6.7 to 12.5 MeV; α₃) and (1982AOZZ; 13.8 to 16.5 MeV; α₀). The yield curves have been fitted in terms of a large number of states in ¹⁸F: see Tables 18.15 (in PDF or PS) here and 18.16 (in PDF or PS) in (1978AJ03).

A detailed study by (1973JO13) of the isospin-forbidden α₁ yield, analyzed by S-matrix theory, identifies a large number of isospin mixed states in ¹⁸F, possibly as many as 138 with 9.2 < E_x < 19.4 MeV. The reaction mechanism appears to be almost entirely compound nuclear. The isospin impurity, averaged over 1 MeV intervals, is 3 - 10% for the above E_x range. The average coherence width increases from ≈ 100 keV at E_x = 14 MeV to ≈ 500 keV at E_x = 20 MeV. The level densities appear to be consistent with predictions of the Fermi-gas model (1973JO13). See also (1981JO1D). [For mixed isospin states observed in ¹⁴N(α, α₁) see Table 18.14 (in PDF or PS) in (1978AJ03)].

Polarization measurements are reported for E_d = 6.8 to 16 MeV: see (1978AJ03). The T₂₁ analyzing power of the transition to ¹⁴N*(4.91) [0^-] has been measured at E_d = 8.06 MeV (θ = 45°) to 0.5% (1981KA21). See also (1979TO1A, 1980PR1A, 1981TO1G), (1979MA2Q: applications), (1978SE01, 1979SE04; theor.) and ¹⁴N in (1981AJ01).

28. ¹⁶O(d, ⁶Li)¹²C Q_m = -5.6885 E_b = 7.5263

See (1978AJ03).

29. ¹⁶O(t, n)¹⁸F Q_m = 1.2690

See (1978AJ03). See also (1976HE1N) and (1980KU1H; applied).

30. ¹⁶O(³He, p)¹⁸F Q_m = 2.0328

Excitation energies derived from measurements of γ-rays are displayed in Table 18.16 (in PDF or PS), together with l-assignments obtained from distorted-wave analyses, and J^π; T and K^π assignments from branching ratios, radiative widths, linear polarization, γ-ray angular distributions and τ_m measurements [see also Tables 18.12 (in PDF or PS) and 18.13 (in PDF or PS)]. Studies of this reaction, together with the work on ¹⁴N(α, γ) and ¹⁷O(p, γ), have defined the low-lying states of ¹⁸F.

The g-factor of ¹⁸F*(0.94) [J^π = 3⁺] is +0.54 ± 0.06 (1981ST21), 0.58 ± 0.07 (1978GO22). τ_m of ¹⁸F*(1.04) = 2.7 ± 0.7 fsec. The weighted mean "best" value [see Table 18.12 (in PDF or PS)] is 2.7 ± 0.4 fsec. This leads to |M|² = 10.3 ± 1.5 W.u., and using the E1 strength of the ¹⁸F*(1.08 → g.s.) decay leads to a value for the circular polarization of the 1.08 → g.s. γ-ray [P_γ] [0^-; T = 0 to 1⁺; 0] = ± (5.8 ± 0.4) keV^-1< 1.04|V^PNC|1.08 > (1981KE04). The experimental value for P_γ = (-0.7 ± 2.0) × 10^-3 (1978BA08). (1981AD1E) reports a best value of P_γ = (-0.1 ± 1.2) × 10^-3. The importance of the decays of ¹⁸F*(1.04, 1.08) [J^π = 0⁺, T = 1; J^π = 0^-, T = 1, respectively] lies in testing the parity non-conserving (PNC) component of nuclear forces: see also (1980BI11), (1981HA1H) and (1980HA41; theor.). The magnetic moment of ¹⁸F*(1.13) = +2.855 ± 0.030 nm, in agreement with shell-model predictions for a (1d²_5/2)_5⁺ state: see (1978AJ03). See also (1979HAYZ), (1977FI13, 1980HE06; applied) and ¹⁹Ne.

31. ¹⁶O(α, d)¹⁸F Q_m = -16.3204

Angular distributions of the deuteron groups to ¹⁸F*(1.12) [J^π = 5⁺] have been studied at E_α = 28.0 to 33.6 MeV (1978CO10, 1979CO1P). See also ²⁰Ne and (1972AJ02).

32. ¹⁶O(⁶Li, α)¹⁸F Q_m = 6.053

Angular distributions for α₀ are reported at E(⁶Li) = 5.5 to 13.3 and 26 MeV: see (1978AJ03). At E(⁶Li) = 34 MeV angular distributions are reported to ¹⁸F*(0, 0.94, 1.1 [unres.]) and forward angle data has been obtained for ¹⁸F*(2.10, 3.72, 3.79, 3.84). The angular distributions for the first three groups are forward peaked and show little structure at back angles. ¹⁸F*(1.04, 3.06) are not observed, as expected from isospin conservation. States at E_x = 4.12, 4.23, 4.4, 5.61, 6.11, 6.20, 6.53, 6.80 and 6.88 were populated (1976MO24). See also (1981MA26; theor.).

33. ¹⁶O(¹¹B, ⁹Be)¹⁸F Q_m = -8.290

Forward angle differential cross sections are reported at E(¹¹B) = 115 MeV to ¹⁸F*(1.1) [J^π = 3⁺ + 5⁺] and to ¹⁸F*(4.65) [J^π = 4⁺] (1980PR09). See also (1979RA10).

34. (a) ¹⁶O(¹²C, ¹⁰B)¹⁸F Q_m = -17.661
(b) ¹⁶O(¹³C, ¹¹B)¹⁸F Q_m = -9.4074

Forward angle differential cross sections are reported at E(¹³C) = 105 MeV ¹⁸F*(1.12, 4.65) (1980PR09). For reaction (a) see (1978AJ03).

35. ¹⁶O(¹⁴N, ¹²C)¹⁸F Q_m = -2.7461

Angular distributions are reported at E(¹⁴N) = 76.2 MeV to ¹⁸F_g.s. (1977MO1A).

36. ¹⁶O(¹⁶O, ¹⁴N)¹⁸F Q_m = -13.2100

See (1978AJ03).

37. ¹⁷O(p, γ)¹⁸F Q_m = 5.607
Q₀ = 5606.2 ± 0.6 keV (1976RO1T); see also (1978SE08).

Gamma-ray measurements lead to the very accurate E_x determinations for ¹⁸F states below 6.2 MeV: see Table 18.17 (in PDF or PS). Observed resonances are displayed in Table 18.18 (in PDF or PS); branching ratios, radiative widths and multipole mixing ratios are shown in Table 18.12 (in PDF or PS); and τ_m in Table 18.13 (in PDF or PS).

The direct capture cross section has been studied for E_p = 0.3 to 1.9 MeV: ¹⁸F*(5.603, 5.605, 5.668, 5.786) have J^π = 1⁺, 1^-, 1^- and 2^-. The 1^- states have mixed isospin. Astrophysical considerations are discussed in (1978AJ03) and (1975ZI1A, 1977RO1H, 1978RO1D).

38. ¹⁷O(p, n)¹⁷F Q_m = -3.544 E_b = 5.607

Observed resonances are displayed in Table 18.18 (in PDF or PS). See also (1978AJ03).

39. ¹⁷O(p, p)¹⁷O E_b = 5.607

The elastic scattering has been studied for E_p = 0.5 to 13 MeV [see (1978AJ03)] and 1.4 to 3.0 MeV (1977SE12, 1978SE08): observed anomalies are displayed in Table 18.18 (in PDF or PS).

40. ¹⁷O(p, d)¹⁶O Q_m = -1.920 E_b = 5.607

See (1978AJ03).

41. ¹⁷O(p, α)¹⁴N Q_m = 1.191 E_b = 5.607

The yield of α₀ shows a number of resonances for E_p = 0.49 to 3.0 MeV: see Table 18.18 (in PDF or PS). The R-matrix fit of (1979KI13), obtained from data from E_p = 400 to 1400 keV, confirms the earlier result [see, e.g., reaction 31 in (1978AJ03)] that a significant quantity of ¹⁷O is burned up in the (p, γ) rather than in the (p, α) reaction for a wide range of stellar temperatures (1979KI13). See also (1977RO1H, 1978RO1D; astrophys.).

42. ¹⁷O(d, n)¹⁸F Q_m = 3.382

See (1972AJ02).

43. ¹⁷O(³He, d)¹⁸F Q_m = 0.113

At E(³He) = 15 MeV, DWBA analysis of angular distributions of deuteron groups corresponding to the ground state of ¹⁸F [l = 2] and to the excited states at 0.94 [l = 0 + 2], 1.04 [2], 1.12 [2], 2.53 [0 + 2], 3.06 [0 + 2], 3.84 [0 + 2], 4.12 [0 + 2], 4.66 [2] and 4.96 [l = 0 + 2] have been obtained by (1969PO11) who also report spectroscopic information. Thus all these states have even parity and ¹⁸F*(4.11) may be assigned J^π = (2⁺) or 3⁺. Since l = 2 for ¹⁸F*(4.65), J^π ≤ 5⁺, with 4⁺ most likely (1969PO11). See also (1979SA31; theor.).

44. ¹⁷O(¹²C, ¹¹B)¹⁸F Q_m = -10.350

Forward angle differential cross sections are reported for the transition to ¹⁸F*(1.12) at E(¹²C) = 115 MeV (1980PR09).

45. ¹⁸O(p, n)¹⁸F Q_m = -2.4379

Angular distributions of a number of neutron groups are reported for E_p = 5.5 to 13.5 MeV: see (1978AJ03). The τ_m of ¹⁸F*(1.04) [J^π = 0⁺; T = 1] is 2.7^+0.6_-0.4 fsec (1980KE05): see Table 18.13 (in PDF or PS). See also ¹⁹F.

46. ¹⁸O(³He, t)¹⁸F Q_m = -1.6742

At E(³He) = 16 MeV, the triton spectrum is dominated by strong groups to the ground and 0.94 MeV excited states and to the 0⁺ and 2⁺, T = 1 states at E_x = 1.04 and 3.06 MeV. Angular distributions have been measured and analyzed by DWBA for the tritons corresponding to these states and to ¹⁸F*(1.08, 1.12, 1.70, 2.10, 3.13, 3.36, 3.72, 3.79, 3.84, 4.12, 4.23, 4.36, 4.40, 4.65, 4.75). The angular distributions are consistent with the J^π assignments shown in Table 18.11 (in PDF or PS), except for the distribution to ¹⁸F*(1.04) (1970DU08). At E(³He) = 17.3 MeV, angular distributions to ¹⁸F states with E_x < 4 MeV have been analyzed using DWBA and a two-body interaction between the incident and target nucleons. An exact coupled-channel calculation was also made for the transition to ¹⁸F*(1.04) (1968HA30). At E(pol. ³He) = 33 MeV the analyzing power angular distribution for t₀ has been measured by (1981BA1G).

47. ¹⁸O(⁶Li, ⁶He)¹⁸F Q_m = -5.165

At E(⁶Li) = 34 MeV angular distributions have been obtained for the transitions to ¹⁸F*(0, 0.94): there appears to be a sizeable contribution due to two-step processes: see (1978AJ03).

48. ¹⁸Ne(β⁺)¹⁸F Q_m = 4.447

The half-life of ¹⁸Ne is 1672 ± 4 msec (see ¹⁸Ne). The decay is to ¹⁸F*(0, 1.04, 1.08, 1.70): see Table 18.19 (in PDF or PS) for the branching ratios and log ft values.

49. ¹⁹F(γ, n)¹⁸F Q_m = -10.4313

Cross sections to 30 MeV for the transitions to ¹⁸F*(0.94, 1.04, 1.08, 3.06, 3.13, 4.75) are reported by (1979TH05). See also (1978AJ03), (1980YA08; applied) and ¹⁹F.

50. ¹⁹F(n, 2n)¹⁸F Q_m = -10.4313

See (1978CO18, 1980CO1U). See also ²⁰F and (1978AJ03).

51. ¹⁹F(p, d)¹⁸F Q_m = -8.2067

Angular distributions of the d₀ group have been measured at E_p = 16 to 155.6 MeV: l_n = 0: see (1972AJ02) and (1977GU14: 17.7 MeV). At E_p = 19.3 MeV angular distributions are also reported to excited states of ¹⁸F: see Table 18.20 (in PDF or PS). The angular distributions associated with 0h - 2p states in ¹⁸F are only qualitatively accounted for by DWBA. Those corresponding to 1h - 3p negative-parity states generally cannot be accounted for by a single-step mechanism, while the distributions to states arising from 2p - 4h configurations do not show the features associated with direct interaction (1980DE05). See also (1982MA1H) and (1978AJ03).

52. ¹⁹F(d, t)¹⁸F Q_m = -4.1740

Angular distributions of triton groups have been reported at E_d = 8.9 (t₀, t₁, t₃) and 14.8 MeV (t₀): see (1972AJ02). See also (1978AJ03).

53. ¹⁹F(³He, α)¹⁸F Q_m = 10.1465

Many α-particle groups have been observed [see Table 18.21 (in PDF or PS) in (1978AJ03)].

54. (a) ¹⁹F(¹⁰B, ¹¹B)¹⁸F Q_m = 1.024
(b) ¹⁹F(¹⁴N, ¹⁵N)¹⁸F Q_m = 0.4021
(c) ¹⁹F(¹⁹F, ²⁰F)¹⁸F Q_m = -3.830

See (1972AJ02).

55. ²⁰Ne(p, ³He)¹⁸F Q_m = -15.558

At E_p = 45 MeV, ¹⁸F*(0, 1.04, 1.70, 3.06, 6.27) are populated: see (1978AJ03).

56. ²⁰Ne(d, α)¹⁸F Q_m = 2.7954

At E_d = 11 MeV α-groups are observed to many states of ¹⁸F with E_x < 7 MeV. Weak or absent (each ≤ 0.3% of the total yield at 30°) are the groups corresponding to ¹⁸F*(1.04, 3.06, 4.66, 4.74, 4.96): T = 1 for these states (1969PO11). Angular distributions at E_d = 6.66, 7.29, 7.93 and 12.95 MeV have been obtained for the α-groups to ¹⁸F*(2.10 [not 12.95 MeV], 2.52, 3.06 [2⁺; 1], 3.13, 3.36, 4.12). The ratio of the total cross section for the isospin-forbidden transition to ¹⁸F*(3.06) to the total cross section of four T = 0 states ranges from 6% to 40%. The average is 21% suggesting isospin mixing in the compound nucleus: the yield curves show strong structures particularly in the range 5 to 9 MeV (1973HR03). Angular distributions have also been measured at E_d = 2 to 14.7 MeV: see (1978AJ03). Measurements of the tensor analyzing power for E_d-bar = 10.25 to 12.0 MeV leads to assignments of unnatural parity for ¹⁸F*(0, 0.94, 1.08 + 1.12, 1.70, 2.10, 3.36, 3.72, 4.12, 4.23, 4.36, 4.40, 5.603 + 5.605 + 5.67, 5.79, 6.10 + 6.10, 6.14 + 6.16, 6.31, 6.48) and to natural parity for ¹⁸F*(3.79, 3.84, 4.86): assignments of J^π = 2^-, 1⁺, 0⁺, 1^-, 1⁺, 3⁺, 3⁺ are made for ¹⁸F*(4.23, 4.36, 4.75, 4.86, 5.603, 6.16, 6.48) [all T = 0 except ¹⁸F*(4.75)] (1978DA02).

57. ²⁰Ne(α, ⁶Li)¹⁸F Q_m = -19.578

See (1979LE1R, 1980LE21; theor.).

58. ²⁴Mg(¹²C, ¹⁸F)¹⁸F Q_m = -15.676

See (1978NO02).