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GENERAL: See also (1975AJ02) and Table 12.1 [Table of Energy Levels] (in PDF or PS).

Special reactions: (1975VO09, 1977AR06, 1979NA1E).

General reviews: (1973TO16, 1974CE1A).

Theoretical papers: (1975BE31, 1976BA24, 1976BE1G, 1976IR1B, 1977SE1D).

Mass of ¹²Be: The Q-value of the ¹⁰Be(t, p) reaction (-4809 ± 15 keV) (1978AL29) leads to an atomic mass excess of 25078 ± 15 keV for ¹²Be which we adopt. See also (1975AJ02, 1975JE02).

1. 12Be(β-)12B

Qm = 11.708

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 ¹²B_g.s.. The upper limit to a branch involving delayed neutrons is 1% (1978AL10). See also (1975AJ02) and (1973TA30; theor.).

2. 7Li(7Li, 2p)12Be

Qm = -9.840

This reaction has been studied at E(⁷Li) = 25.0 to 30.1 MeV (1971HO26).

3. 10Be(t, p)12Be	Qm = -4.809
	Q0 = -4809 ± 15 keV (1978AL29).

At E_t = 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 ¹²Be_g.s.] (1978AL10). At E_t = 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 E_x = 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 E_x = 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 E_x ≈ 4.4 MeV but is observed at 2.1 MeV. Model calculations suggest a 0⁺ state at E_x ≈ 2.35 MeV (1976BA24). See also ¹²O.

4. 12C(π-, π+)12Be

Qm = -25.078

At E_π^- = 164 MeV, ¹²Be*(0, 2.10 + 2.71 (?)) are populated (1978SE07).

5. 14C(18O, 20Ne)12Be

Qm = -15.798

At E(¹⁸O) = 88.7 MeV, ¹²Be*(0, 2.09 ± 0.05) are populated (1974BA15).