Information on mass chains and nuclides

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GENERAL: See also (1984AJ01) and Table 7.1 [Table of Energy Levels] (in PDF or PS).

Hypernuclei: (1982KA1D, 1983FE07, 1984AS1D, 1985KO1G, 1986DA1B, 1986DO01, 1986ME1F).

Other topics: (1983ANZQ, 1984FR13, 1984VA06, 1986GI10, 1986SH1L, 1987BO40, 1987GOZN, 1987PE1C).

Mass of ⁷He: The atomic mass excess of ⁷He is 26.11 ± 0.03 MeV: ⁷He is then unbound with respect to decay into ⁶He + n by 0.44 MeV: see (1984AJ01). The ground state is calculated to have J^π = 3/2^- and to be unstable with respect to decay into ⁶He + n by about 1 MeV (1985PO10). [I am indebted to F.C. Barker for his comments.] See also (1987BEYI).

1. 7Li(π-, γ)7He

Qm = 128.37

Capture γ-rays from the transition to ⁷He_g.s. are reported by (1986PE05).

2. 7Li(n, p)7He

Qm = -10.42

The proton group corresponding to ⁷He_g.s. has Γ < 0.2 MeV: see (1979AJ01). At E_n = 60 MeV broad bumps in the spectra are ascribed to states at E_x ≈ 20 ± 1 MeV [Γ = 9 ± 2 MeV] and, possibly, at ≈ 6 MeV (1983BR32, 1984BR03) [see for discussion of the GDR]. See also (1987HE24) and (1987BR32).

3. 7Li(t, 3He)7He

Qm = -11.18

The ³He particles to the ground state of ⁷He have been observed at E_t = 22 MeV. The width of the ground state is 160 ± 30 keV; for a radius of 2.2 fm and l_n = 1, this width is 0.22 of the Wigner limit. The angular distribution is peaked in the forward direction. No other states of ⁷He were observed for E_x < 2.4 MeV: see (1979AJ01).

4. (a) 7Li(7Li, 7Be)7He	Qm = -12.07
(b) 7Li(11B, 11C)7He	Qm = -13.19
(c) 9Be(6Li, 8B)7He	Qm = -23.60
(d) 9Be(9Be, 11C)7He	Qm = -14.07
(e) 9Be(11B, 13N)7He	Qm = -11.44
(f) 9Be(14C, 16O)7He	Qm = -7.01

At E(⁶Li) = 72 MeV and at E(⁷Li) = 70 MeV (reactions (a) and (c)) there is no evidence for excited states with Γ ≤ 2 MeV for E_x < 10 MeV (1985AL1G, 1985AL29, 1985ALZL, 1985ALZM). The ground state of ⁷He is strongly populated. Reactions (b), (d), (e) and (f) have been investigated at E(¹¹B) = 88, E(⁹Be) = 106.7 and E(¹⁴C) = 152.6 MeV. The ground state of ⁷He is populated. There is some evidence for a second state in reaction (f) at E_x = 2.9 ± 0.5, Γ = 1.5 ± 0.5 MeV (1987BEYI). See also (1979AJ01) and (1988BEYJ).