(See the Isobar Diagram for 7He)
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 Jπ = 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).
Capture γ-rays from the transition to 7Heg.s. are reported by (1986PE05).
The proton group corresponding to 7Heg.s. has Γ < 0.2 MeV: see (1979AJ01). At En = 60 MeV broad bumps in the spectra are ascribed to states at Ex ≈ 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).
The 3He particles to the ground state of 7He have been observed at Et = 22 MeV. The width of the ground state is 160 ± 30 keV; for a radius of 2.2 fm and ln = 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 Ex < 2.4 MeV: see (1979AJ01).
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 Ex < 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 Ex = 2.9 ± 0.5, Γ = 1.5 ± 0.5 MeV (1987BEYI). See also (1979AJ01) and (1988BEYJ).