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GENERAL: See also (1975AJ02) and Table 11.1 [Table of Energy Levels] (in PDF or PS).

Model calculations: (1974TA1E, 1975MI12, 1976IR1B, 1977SE1D, 1978BO31, 1979BE1H).

Special reactions: (1975FE1A, 1976OS04, 1977AR06, 1977YA1B).

Muon capture (See also reaction 2.): (1978DE15).

Pion reactions: (1975CO06, 1976CO1M, 1977DO06, 1977GE1D).

Ground state of ¹¹Be: (1975BE31, 1978BO31).

1. 11Be(β-)11B

Qm = 11.508

The decay proceeds to ¹¹B*(0, 2.12, 5.02, 6.79, 7.98, 9.88) with J^π = 3/2^-, 1/2^-, 3/2^-, 1/2⁺, 3/2⁺, 3/2⁺, respectively: see Table 11.15 (in PDF or PS) (1971AL07). The half-life is 13.81 ± 0.08 sec (1970AL21). The nature of the decay indicates J = 1/2 or 3/2, even parity for the ground state of ¹¹Be: see (1971AL07). See also (1977TE01; theor.).

2. 9Be(t, p)11Be

Qm = -1.167

Proton groups have been observed to many states of ¹¹Be: see Table 11.2 (in PDF or PS) (1962PU01, 1972AJ01, 1978AJ02). The first excited state has an excitation energy of 319.8 ± 0.2 keV and τ_m = 0.18 ± 0.06 psec corresponding to a very strong E1 transition of 0.33 W.u. (1971HA25). The J^π of ¹¹Be*(0.32) is 1/2^-, as determined by a study of the yield of 320 keV γ-rays as a function of time in μ^- capture by ¹¹B (1968DE20). The strength of the E1 transition fixes J^π of ¹¹Be_g.s. to be 1/2⁺ or 3/2⁺, using the parity information obtained from the nature of the β^- decay of the ground state [see reaction 1]. ¹¹Be*(5.24, 6.71, 8.82) are strongly populated at E_t = 20 MeV indicating that these states have a large overlap with ⁹Be_g.s. + two neutrons (1972AJ01).

3. 10Be(n, γ)11Be

Qm = 0.503

See (1975AJ02).

4. 10Be(d, p)11Be

Qm = -1.722

Angular distributions of the p₀ and p₁ groups have been measured at E_d = 6 MeV (1970GO11: p₁ only) and 12 MeV (1970AU02): l_n = 0 [and therefore J^π = 1/2⁺ for ¹¹Be(0)] and 1, S = 0.73 ± 0.06 and 0.63 ± 0.15, respectively (1970AU02). At E_d = 25 MeV ¹¹Be*(0, 0.32, 1.78) are strongly populated: S = 0.77, 0.96 and 0.50, respectively, J^π = (5/2, 3/2)⁺ for ¹¹Be*(1.78) [l_n = 2] (1979ZW01).

5. 11Li(β-)11Be

Qm = 20.76

See ¹¹Li.

6. 11B(n, p)11Be

Qm = -10.726

See ¹²B.

7. 13C(6Li, 8B)11Be

Qm = -25.886

At E(⁶Li) = 80 MeV, ¹¹Be*(0.32) is strongly populated and the angular distribution to this state has been measured (1977WE03). ¹¹Be*(2.69, 4.0) are also observed. It is suggested that these states have odd parity (1976WE09) [see, however, reaction 2 for evidence concerning the positive parity of ¹¹Be*(2.69)]. See also (1977WE1B).

8. 14C(18O, 21Ne)11Be

Qm = -12.206

See (1974BA15).