(See Energy Level Diagrams for 12Be)
The half-life of 12Be is 24.4 ± 3.0 msec (1978AL10): log ft = 3.84 ± 0.06 (M.J. Martin, Nuclear Data Project, ORNL.) assuming the decay is to 12Bg.s.. The upper limit to a branch involving delayed neutrons is 1% (1978AL10). See also (1975AJ02) and (1973TA30; theor.).
This reaction has been studied at E(7Li) = 25.0 to 30.1 MeV (1971HO26).
At Et = 12 MeV, 12Be*(2.10) is populated and (p, γ) angular correlations lead to an assignment of J = 2 [it is not excluded that a 0+ state might be unresolved; it would not, of course, γ-decay to 12Beg.s.] (1978AL10). At Et = 17 MeV proton groups are observed to the states shown in Table 12.1 (in PDF or PS). Assignment of a possible group to a state at ≈ 2.24 MeV is very tentative. The energy of 12Be*(2.10) is measured to be 2089 ± 20 keV. The two highest states have an intrinsic width. There is no evidence for a state at Ex = 0.81 MeV suggested in reaction 2. From the measured atomic mass excess of 12Be, d, the cubic factor in the IMME, is calculated to be +2.8 ± 8.6 keV and the first T = 2 state in 12N should occur at Ex = 12.27 ± 0.04 MeV (1978AL29): compare with 12O. (1976BA24) suggests that first two T = 2 states do not belong exclusively to the lowest configuration (1s41p8), for which the first 2+; T = 2 excited state is expected to have Ex ≈ 4.4 MeV but is observed at 2.1 MeV. Model calculations suggest a 0+ state at Ex ≈ 2.35 MeV (1976BA24). See also 12O.
At Eπ- = 164 MeV, 12Be*(0, 2.10 + 2.71 (?)) are populated (1978SE07).
At E(18O) = 88.7 MeV, 12Be*(0, 2.09 ± 0.05) are populated (1974BA15).