A=8Li (1979AJ01)

The β-decay leads mainly to ⁸Be*(2.9): see ⁸Be. The adopted half-life [see (1974AJ01)] = 842 ± 6 msec, log ft = 5.61 (B. Zimmerman, private communication). The distribution of recoil momenta indicates J^π = 2⁺ for ⁸Li_g.s.. The coefficient for the angular correlation between β^-, ν_e-bar and α-particles, b = -0.88 ± 0.08 (1965GR25), -1.01 ± 0.07 (1966EI02), in substantial agreement with b = -1, expected from axial vector coupling. (1975MI04) have looked at the symmetry of the β-decay in polarized ⁸Li nuclei and have determined the quadrupole moment for ⁸Li_g.s.: see the "GENERAL" section here. See also reaction 28 in ⁸Be.

2. ⁶Li(t, p)⁸Li Q_m = 0.801

Angular distributions have been obtained at E_t = 23 MeV for the proton groups to ⁸Li*(0, 0.98, 2.26, 6.54 ± 0.03); Γ_c.m. for ⁸Li*(2.26, 6.54) = 35 ± 10 and 35 ± 15 keV, respectively; J for the latter is ≥ 4 (1978AJ02).

3. ⁷Li(n, γ)⁸Li Q_m = 2.033

The cross section for capture radiation has been measured for E_n = 40 to 1000 keV: it decreases from 50 μb to 5 μb over the interval. The cross section shows the resonance corresponding to ⁸Li*(2.26): Γ_γ = 0.07 ± 0.03 eV (1959IM04); E_res = 254 ± 3 keV, Γ_n = 31 ± 7 keV (1971AL09): see Table 8.2 (in PDF or PS). For unpublished data see (1974AJ01). See also (1976GAYV).

4. ⁷Li(n, n)⁷Li E_b = 2.033

The thermal cross section is 1.07 ± 0.04 b (1960HU08); the coherent scattering length (thermal, bound) is -2.1 ± 0.1 fm (see (1973MU14)). See also (1974RO20). Total cross-section measurements have been reported for E_n = 5 eV to 30 MeV [see (1974AJ01, 1976GAYV)] and by (1976KN1D, 1976LA1C; E_n = 4 to 7.5 MeV), (1974HY01; 14.1 MeV) and (1976MI1C; 14.6 MeV). For polarization measurements see (1966LA04, 1974AJ01). For angular distribution measurements see ⁷Li.

A pronounced resonance is observed at E_n = 261 keV with J^π = 3⁺, formed by p-waves (Table 8.2 (in PDF or PS)) (1970ME1C). A good account of the polarization is given by the assumption of levels at E_n = 0.25 and 3.4 MeV, with J^π = 3⁺ and 2^-, together with a broad J^π = 3^- level at higher energy (1964LA19). Broad peaks are reported at E_n = 4.6 and 5.8 MeV (± 0.1 MeV) [⁸Li*(6.1, 7.1)] with Γ ≈ 1.0 and 0.4 MeV, respectively, and there is indication of a narrow peak at E_n = 5.1 MeV [⁸Li*(6.5)] with Γ « 80 keV and of a weak, broad peak at E_n = 3.7 MeV (1971FO1P, 1971FO24) [and see (1974AJ01)]. See also (1977ST24, 1978ST20; theor.).

5. ⁷Li(n, n')⁷Li* E_b = 2.033

The exciation function for 0.48 MeV γ-rays shows an abrupt rise from threshold (indicating s-wave formation and emission) and a broad maximum (Γ ≈ 1 MeV) at E_n = 1.35 MeV. A good fit is obtained with either J^π = 1^- or 1⁺ (2⁺ not excluded), Γ_lab = 1.14 MeV (1955FR10). At higher energies a prominent peak is observed at E_n = 3.8 MeV (Γ_lab = 0.75 MeV) and there is some indication of a broad resonance (Γ_lab = 1.30 MeV) at E_n = 5.0 MeV. The two resonances are interpreted as being due to states with J^π = 2⁺ or 3⁺ [⁸Li*(5.4)] [see, however, (1978ST20)] and J^π = 3⁺ or 3^- [⁸Li*(6.4)] [(1972PR03): Γ_λ, γ²_λ and θ²_λ are listed for these two states under various assumptions]. (1977BA62) predicts a 2^- state at E_x = 2.74 MeV and 1^- states at 3.52 and 5.4 MeV with Γ ≈ 1.8, 2.5 and 3.8 MeV. The excitation function for 0.48 MeV γ-rays has been measured at 125° for E_n = 0.4 to 20 MeV: it shows the structures described above followed by a decrease in the cross section from E_n = 6 to 20 MeV with some evidence of structures at E_n = 6.8 and 8 MeV (1977DI11).

Cross-section measurements have also been reported for E_n = 0.57 to 4.0 MeV (1976SM08), 4.0 to 7.5 MeV (1977KN1B) and 7 to 13 MeV (1976BI1B; n₀₊₁, n₂). See also (1976MI1C, 1978LI1C) and the review in (1976GAYV). For applications see (1974ST1D).

6. ⁷Li(n, 2n)⁶Li Q_m = -7.251 E_b = 2.033

See (1974KO35, 1976GAYV).

7. ⁷Li(n, p)⁷He Q_m = -10.40 E_b = 2.033

See (1977RI07) and ⁷He. See also (1976SL2A).

8. ⁷Li(n, d)⁶He Q_m = -7.751 E_b = 2.033

See ⁶He. See also (1976SL2A).

9. ⁷Li(n, t)⁴He + n Q_m = -2.467 E_b = 2.033

The cross section rises to 450 mb at E_n ≈ 8 MeV and thereafter decreases slowly to 300 mb at E_n = 15 MeV (1976GAYV). See also (1975VO1C, 1978QA01), (1974ST1D; applied) and (1976SL2A).

10. ⁷Li(d, p)⁸Li Q_m = -0.192

Angular distributions of the p₀ and p₁ groups [l_n = 1] at E_d = 12 MeV have been analyzed by DWBA: S_exp = 0.87 and 0.48 respectively for ⁸Li*(0, 0.98) [S_exp/S_theor = 0.84, 1.09] (1967SC29). Angular distributions have also been measured at several energies in the range E_d = 0.49 → 3.44 MeV (p₀) and 0.95 to 2.94 MeV (p₁) by (1975MC02). The first excited state decays by emitting a 980 ± 10 keV γ-ray. The transition is M1 (1962CH14). The lifetime of ⁸Li*(0.98) is 10.1 ± 4.5 fsec (1971TH02). See also (1975MI04, 1978HA1K), (1974AJ01, 1976HA1J) and (1974LO10, 1975KU27, 1976KU07; theor.).

11. ⁷Li(t, d)⁸Li Q_m = -4.225

See ¹⁰Be in (1974AJ01).

12. ⁸He(β^-)⁸Li Q_m = 10.649

See ⁸He.

13. ⁹Be(γ, p)⁸Li Q_m = -16.888

See ⁹Be.

14. ⁹Be(e, ep)⁸Li Q_m = -16.888

At E_e = 801 MeV two groups are observed at Q = -28.7 ± 0.1 and -16.9 ± 0.1 MeV corresponding to the ejection of 1s and 1p protons (1974GO35). See also ⁹Be and (1977BE1Q, 1977MO1F).

15. ⁹Be(n, d)⁸Li Q_m = -14.663

See ¹⁰Be.

16. ⁹Be(π⁺, π⁺p)⁸Li Q_m = -16.888

The population of ⁸Li*(0.98) and its subsequent γ-decay are reported by (1978MO01).

17. ⁹Be(p, 2p)⁸Li Q_m = -16.888

The summed proton spectrum at E_p = 156 MeV shows peaks corresponding to ⁸Li(0) and ⁸Li*(0.98 + 2.26) [unresolved]. In addition s-states [J^π = 1^-, 2^-] are suggested at E_x = 9 and 16 MeV, with Γ_c.m. ≈ 6 and 8 MeV: the latter may actually be due to continuum protons (1967RO06). See also ⁹Be.

18. ⁹Be(d, ³He)⁸Li Q_m = -11.394

Angular distributions have been reported for the ³He ions to ⁸Li*(0, 0.98, 2.26, 6.53) at E_d = 27.97 MeV (1977OO01; C²S(abs.) = 1.63, 0.61, 0.48, 0.092) and 52 MeV (1975SC41; S_{p_3/2} = 1.50, 0.63, 0.50 for the first three states, with the ground state value normalized to the predicted theoretical value). The distributions to ⁸Li*(6.53) [Γ < 100 keV (1974DI1A, 1975DI1B)] are featureless (1975DI1B, 1975SC41, 1977OO01). See reaction 32 [⁹Be(d, t)] in ⁸Be (1977OO01). At E_d = 80 MeV, (1974DI1A, 1975DI1B; abstracts) report a broad peak at E_x ≈ 9 MeV corresponding to s-shell pickup. See also (1975RO1E).

19. ⁹Be(t, α)⁸Li Q_m = 2.926

At E_t = 12.98 MeV, α-particle groups are observed to ⁸Li*(0, 0.98, 2.26) and to a state at E_x = 6.530 ± 0.020 MeV with Γ_c.m. < 40 keV (1965WA12). For angular distributions to these four states, see (1968AJ01): the distribution of the α-particles to ⁸Li*(6.53) is rather featureless and does not involve a forward maximum, suggesting l > 1. A large l-transfer is consistent with the narrow width of this unbound state (1968AJ01). See also (1974AJ01) for unpublished measurements and earlier work.

The mean lifetime, τ_m = 14 ± 5 fsec for ⁸Li*(0.98): E_x = 980.80 ± 0.10 keV (1972CO09). See also ¹²B in (1975AJ02).

20. ⁹Be(⁷Li, ⁸Be)⁸Li Q_m = 0.368

See (1974KE1C) and (1974AJ01).

21. ¹⁰Be(p, ³He)⁸Li Q_m = -15.982

At E_p = 45 MeV ³He ions are observed to a state of E_x = 10.8222 ± 0.0055 MeV (Γ_c.m. < 12 keV): the angular distributions for the transition to this state, and to its analog (⁸Be*(27.49)), measured in the mirror reaction [¹⁰Be(p, t)⁸Be] are very similar. They are both consistent with L = 0 using a DWBA (LZR) analysis (1975RO01). The particle decay of the T = 2 state has been studied by (1975ADZV; abstract).

22. ¹⁰Be(d, α)⁸Li Q_m = 2.372

See ¹²B in (1975AJ02).

23. ¹⁰B(⁶Li, ⁸B)⁸Li Q_m = -17.730

At E(⁶Li) = 80 MeV, ⁸Li*(0, 0.98, 2.26, 6.53) are populated (1976WE09, 1977WE1B).

24. ¹¹B(γ, ³He)⁸Li Q_m = -27.210

See (1963NE07).

25. ¹¹B(n, α)⁸Li Q_m = -6.633

Angular distributions for the α₀ and α₁ groups have been measured at E_n = 14.1 MeV (1973BO26). See also ¹²B in (1975AJ02) and (1977AN1C).

26. ¹²C(α, ⁸B)⁸Li Q_m = -41.444

At E_α = 129 MeV, ⁸B groups are observed to ⁸Li*(0, 0.98, 2.26) (1968MC02).

27. ¹³C(³He, ⁸B)⁸Li Q_m = -25.812

See (1976BE1L).

28. ¹³C(⁷Li, ¹²C)⁸Li Q_m = -2.914

At E(⁷Li) = 34 MeV angular distributions have been measured for the transitions to ⁸Li_g.s. + ¹²C_g.s., ⁸Li*_0.98 + ¹²C_g.s., ⁸Li_g.s. + ¹²C*_4.4 and ⁸Li*_0.98 + ¹²C*_4.4 (1973SC26).

29. ¹⁴N(³He, ⁹C)⁸Li Q_m = -32.064

At E(³He) = 76 MeV ⁸Li*(0, 0.98) are populated (1976RO04).

30. ¹⁸O(⁷Li, ¹⁷O)⁸Li Q_m = -6.012

See (1974AJ01).

31. ²⁴Mg(³He, ¹⁹Na)⁸Li Q_m = -32.876

See (1975BE38).