(See Energy Level Diagrams for 8Li)
Muon and neutrino interactions:(BA77WW).
The β-decay leads mainly to 8Be*(2.9): see 8Be. The adopted half-life [see (74AJ01)] = 842 ± 6 msec, log ft = 5.61 (B. Zimmerman, private communication). The distribution of recoil momenta indicates Jπ = 2+ for 8Lig.s.. The coefficient for the angular correlation between β-, νe-bar and α-particles, b = -0.88 ± 0.08 (GR65P), -1.01 ± 0.07 (EI66), in substantial agreement with b = -1, expected from axial vector coupling. (MI75D) have looked at the symmetry of the β-decay in polarized 8Li nuclei and have determined the quadrupole moment for 8Lig.s.: see the "GENERAL" section here. See also reaction 28 in 8Be.
Angular distributions have been obtained at Et = 23 MeV for the proton groups to 8Li*(0, 0.98, 2.26, 6.54 ± 0.03); Γc.m. for 8Li*(2.26, 6.54) = 35 ± 10 and 35 ± 15 keV, respectively; J for the latter is >/= 4 (AJ78A).
The cross section for capture radiation has been measured for En = 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): Γγ = 0.07 ± 0.03 eV (IM59); Eres = 254 ± 3 keV, Γn = 31 ± 7 keV (AL71C): see Table 8.2 (in PDF or PS). For unpublished data see (74AJ01). See also (GA76F).
The thermal cross section is 1.07 ± 0.04 b (HU60A); the coherent scattering length (thermal, bound) is -2.1 ± 0.1 fm (see (MU73I)). See also (RO74H). Total cross-section measurements have been reported for En = 5 eV to 30 MeV [see (74AJ01, GA76F)] and by (KN76C, LA76D; En = 4 to 7.5 MeV), (HY74; 14.1 MeV) and (MI76B; 14.6 MeV). For polarization measurements see (66LA04, 74AJ01). For angular distribution measurements see 7Li.
A pronounced resonance is observed at En = 261 keV with Jπ = 3+, formed by p-waves (Table 8.2 (in PDF or PS)) (ME70M). A good account of the polarization is given by the assumption of levels at En = 0.25 and 3.4 MeV, with Jπ = 3+ and 2-, together with a broad Jπ = 3- level at higher energy (LA64F). Broad peaks are reported at En = 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 En = 5.1 MeV [8Li*(6.5)] with Γ « 80 keV and of a weak, broad peak at En = 3.7 MeV (FO71A) [and see (74AJ01)]. See also (ST77T, ST78C; theor.).
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 En = 1.35 MeV. A good fit is obtained with either Jπ = 1- or 1+ (2+ not excluded), Γlab = 1.14 MeV (FR55A). At higher energies a prominent peak is observed at En = 3.8 MeV (Γlab = 0.75 MeV) and there is some indication of a broad resonance (Γlab = 1.30 MeV) at En = 5.0 MeV. The two resonances are interpreted as being due to states with Jπ = 2+ or 3+ [8Li*(5.4)] [see, however, (ST78C)] and Jπ = 3+ or 3- [8Li*(6.4)] [(PR72A): Γλ, γ2λ and θ2λ are listed for these two states under various assumptions]. (BA77CC) predicts a 2- state at Ex = 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 En = 0.4 to 20 MeV: it shows the structures described above followed by a decrease in the cross section from En = 6 to 20 MeV with some evidence of structures at En = 6.8 and 8 MeV (DI77D).
Cross-section measurements have also been reported for En = 0.57 to 4.0 MeV (SM76C), 4.0 to 7.5 MeV (KN77B) and 7 to 13 MeV (BI76A; n0+1, n2). See also (MI76B, LI78A) and the review in (GA76F). For applications see (ST74F).
Angular distributions of the p0 and p1 groups [ln = 1] at Ed = 12 MeV have been analyzed by DWBA: Sexp = 0.87 and 0.48 respectively for 8Li*(0, 0.98) [Sexp/Stheor = 0.84, 1.09] (SC67L). Angular distributions have also been measured at several energies in the range Ed = 0.49 --> 3.44 MeV (p0) and 0.95 to 2.94 MeV (p1) by (MC75A). The first excited state decays by emitting a 980 ± 10 keV γ-ray. The transition is M1 (CH62B). The lifetime of 8Li*(0.98) is 10.1 ± 4.5 fsec (TH71B). See also (MI75D, HA78L), (74AJ01, HA76I) and (LO74D, KU75P, KU76G; theor.).
See 10Be in (74AJ01).
The population of 8Li*(0.98) and its subsequent γ-decay are reported by (MO78B).
The summed proton spectrum at Ep = 156 MeV shows peaks corresponding to 8Li(0) and 8Li*(0.98 + 2.26) [unresolved]. In addition s-states [Jπ = 1-, 2-] are suggested at Ex = 9 and 16 MeV, with Γc.m. ~ 6 and 8 MeV: the latter may actually be due to continuum protons (RO67E). See also 9Be.
Angular distributions have been reported for the 3He ions to 8Li*(0, 0.98, 2.26, 6.53) at Ed = 27.97 MeV (OO77; C2S(abs.) = 1.63, 0.61, 0.48, 0.092) and 52 MeV (SC75U; Sp3/2 = 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 (DI75K, DI74A)] are featureless (DI75K, SC75U, OO77). See reaction 32 [9Be(d, t)] in 8Be (OO77). At Ed = 80 MeV, (DI75K, DI74A; abstracts) report a broad peak at Ex ~ 9 MeV corresponding to s-shell pickup. See also (RO75BB).
At Et = 12.98 MeV, α-particle groups are observed to 8Li*(0, 0.98, 2.26) and to a state at Ex = 6.530 ± 0.020 MeV with Γc.m. < 40 keV (WA65G). For angular distributions to these four states, see (AJ68A): 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 (AJ68A). See also (74AJ01) for unpublished measurements and earlier work.
At Ep = 45 MeV 3He ions are observed to a state of Ex = 10.8222 ± 0.0055 MeV (Γc.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 (RO75). The particle decay of the T = 2 state has been studied by (AD75B; abstract).
See 12B in (75AJ02).
At Eα = 129 MeV, 8B groups are observed to 8Li*(0, 0.98, 2.26) (MC68B).
At E(7Li) = 34 MeV angular distributions have been measured for the transitions to 8Lig.s. + 12Cg.s., 8Li*0.98 + 12Cg.s., 8Lig.s. + 12C*4.4 and 8Li*0.98 + 12C*4.4 (SC73M).
At E(3He) = 76 MeV 8Li*(0, 0.98) are populated (RO76E).