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GENERAL: See also (79AJ01) and Table 6.6 [Table of Energy Levels] (in PDF or PS).

Model calculations:(SH79A, HO81L, DE82U, HO82B, KR82A, NG82, VO82B, DE83I).

Other topics:(KO79Z, BA83J, NA83A).

1. (a) 3He(3He, γ)6Be	Qm = 11.489
(b) 3He(3He, p)5Li	Qm = 10.90	Eb = 11.489
(c) 3He(3He, 2p)4He	Qm = 12.8596
(d) 3He(3He, 3He)3He
(e) 3He(3He, pd)3He	Qm = -5.4936
(f) 3He(3He, 2p)2H2H	Qm = -10.987
(g) 3He(3He, 3p)3H	Qm = -6.9544

The yield of γ-rays to ⁶Be*(1.7) (reaction (a)) increases smoothly from 0.4 to 9.3 μb (assuming isotropy) for 0.86 < E(³He) < 11.8 MeV (90°). No transitions were observed to ⁶Be(0) [σ < 0.01 μb at E(³He) = 1.4 MeV]. This is understood in terms of a direct capture of ³He by ³He in the singlet spin state and with zero angular momentum: the 0⁺ --> 0⁺ γ-transition is forbidden. Reaction (a) is thus of negligible astrophysical importance compared to reaction (c): see (79AJ01). The capture cross section from E(³He) = 12 MeV to 27 MeV continues to increase smoothly with energy at first and then shows a broad structure centered at E(³He) = 23 ± 1 MeV [E_x = 23.0 ± 0.5 MeV], Γ_c.m. ~ 5 MeV (VE74A). This appears to be a ³³F cluster resonance which decays by an E1 transition to ⁶Be*(1.7). The γ-ray angular distributions are consistent with J^π = 3^- (VE74A).

The analyzing power angular distribution has been measured at E(pol. ³He) = 14 MeV for the p₀ group (reaction (b)) (KO81Q). See also (79AJ01) and ⁵Li.

Measurements of the total cross section for reaction (c) have been carried out for E(³He) = 60 keV to 2.2 MeV. The measurements of (DW74), down to E_c.m. = 30 keV, eliminate the possibility of a resonance [which might help explain the observed absence of solar neutrinos], unless it is extremely narrow (Γ < ~ 100 eV): θ²_p ~ 3 x 10^-6 (DW74). The cross section factor S(E_c.m.) = [5.2 - 2.8E_c.m. + 1.4E²_c.m.] MeV · b [error in S is ± 20% for E_c.m. > 40 keV] (DW74). For the earlier work see (66LA04, 74AJ01). For polarization measurements (reaction (c)), see (79AJ01).

The elastic scattering (reaction (d)) has been studied for E(³He) = 3 to 32 MeV [see (79AJ01)] and at 120 MeV (TA80Q; also inelastic processes). The excitation function shows a smooth monotonic behavior except for an anmaly at E(³He) = 25 MeV in the L = 3 partial wave corresponding to a broad state in ⁶Be at E_x ~ 24 MeV. Polarization measurements have been carried out at E(pol. ³He) = 17.9 to 32.9 MeV (VL78). A two level R-matrix analysis of the phase shifts (L < / = 5) suggests three broad F-wave states at E_x ~ 23.4(4^-), 26.2(2^-) and 26.7 MeV(3^-) (VL78), in disagreement with the capture γ-ray results described above. See also (79AJ01).

A kinematically complete experiment (reaction (e)) has been performed at E(³He) = 120 MeV: large peaks were observed which appear to correspond to ³He - d quasi-free scattering followed by p - d FSI. No evidence was seen for excited states of ³He (FU78F). See also (TA80Q). At E(³He) = 50, 65 and 78 MeV (LA79S, AL78H) have examined reactions (c), (e), (f), (g) and have compared the results with PWIA: deviations are observed. See also (PI79H), (79AJ01, SL82A), (PE80K, BA82B, TR83B; astrophysics) and (FE78D, FU79Q, BA81BB, HO81L; theor.).

2. 4He(3He, n)6Be

Qm = -9.089

Neutron groups to ⁶Be*(0, 1.7) have been observed at E(³He) = 19.4 to 38.61 MeV: see Table 6.8 (in PDF or PS) in (74AJ01) for the parameters of the first excited state. There is no evidence for other states of ⁶Be with E_x < ~ 5 MeV, not for a state near the ³He threshold at 11.5 MeV: see (79AJ01).

3. (a) 6Li(p, n)6Be	Qm = -5.070
(b) 6Li(p, pn)5Li	Qm = -5.66

Neutron groups have been observed to ⁶Be*(0, 1.7) as has the ground-state threshold. The width of the ground state is 95 ± 28 keV. The parameters of ⁶Be*(1.7) are displayed in Table 6.8 (in PDF or PS) of (74AJ01). Angular distributions have been reported at E_p = 8.3 to 49.4 MeV [see (79AJ01)] and at E_p = 144 MeV (MO80G; n₀). See also (KI82D; E_p = 800 MeV). In reaction (b) (WA77F) report, at E_p = 47 MeV, some evidence for sequential decay via ⁶Be*(15.5 ± 2, 24 ± 2). See also (RA79G, GO80G), (PE82E) and (BA80II, DU80A, GU83B; theor.).

4. 6Li(3He, t)6Be

Qm = -4.307

Triton groups have been observed to ⁶Be*(0, 1.7). The width of the ground state is 89 ± 6 keV. The parameters of the excited state are displayed in Table 6.8 (in PDF or PS) of (74AJ01). No other excited states have been seen with E_x < 13 MeV. There is no evidence for a state near 11.5 MeV; see (79AJ01). The angular distribution of t₀ has been studied by (BA81KK: E(³He) = 33.3 MeV). The α-spectrum following the α + p + p decay of ⁶Be_g.s. has been measured by (GE77A): the yield of low-energy α-particles appears to be enhanced compared with calculations based on the available phase space. The continuum has also been studied by (DE83G). See also (DE81T), (BA79; theor.) and ⁹B.

5. 6Li(6Li, 6He)6Be

Qm = -7.795

See reactions 10 in ⁶He and 20 in ⁶Li.

6. 9Be(3He, 6He)6Be

Qm = -9.687

Discrete states are not observed: see (DE81T, DE83G) [see also for a study of the continuum].