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GENERAL: See also (68AJ02) and Table 11.1 [Table of Energy Levels] (in PDF or PS).

Model calculations: (TA70H, SA73S, SP73, IR74A).

Special reactions: (AR69E, AR71, VO72C, BA73PP, KO73F, WI73J).

Muon capture (See also reaction 2.): (DE67T, DE68L, BE69S, VA70K, BE71S, MU73M).

Pion reactions: (DY62, BE71GG).

Mass of ¹¹Be: The mass excess of ¹¹Be is given as 20.181 ± 0.015 MeV (MA65A) [based on (PU62, RY65)] and as 20.174 ± 0.007 MeV (GO70). (WA71M) adopt 20.177 ± 0.006 MeV, and so do we. See also (TH74).

1. 11Be(β-)11B

Qm = 11.509

The decay proceeds to ¹¹B*(0, 2.12, 5.02, 6.79, 7.98, 9.87) with J^π = 3/2^-, 1/2^-, 3/2^-, 1/2⁺, 3/2⁺ and 3/2⁺, respectively: see Table 11.16 (in PDF or PS) (AL71B). The half-life is 13.81 ± 0.08 sec (AL70I). See also (FL67E, 68AJ02). The nature of the decay indicates J = 1/2 or 3/2, even parity for the ground state of ¹¹Be: see (AL71B).

2. 9Be(t, p)11Be

Qm = -1.167

Proton groups have been observed to many states of ¹¹Be by (PU62: E_t = 14 MeV) and (AJ72A: E_t = 20 MeV): see Table 11.2 (in PDF or PS). 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. (HA71I). 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 (DE68L). 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]. J^π limits for ¹¹Be*(1.79, 2.69, 3.41) are derived from angular distribution studies (PU62, HI64B). ¹¹Be*(5.25, 6.72, 8.84) are strongly populated at E_t = 20 MeV indicating that these states have a large overlap with ⁹Be_g.s. + two neutrons (AJ72A). See also (68AJ02) and (AL70I, AL71B).

3. 9Be(6He, α)11Be

Qm = 6.344

See ¹⁵C in (70AJ04).

4. 10Be(n, γ)11Be

Qm = 0.503

The capture cross section is < 1 mb (E.T. Jurney, private communication).

5. 10Be(d, p)11Be

Qm = -1.722

Angular distributions of the p₀ and p₁ groups have been measured at E_d = 6 MeV (GO70: p₁ only) and 12 MeV (AU70C): 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 (AU70C). E_x = 318 ± 7 keV for ¹¹Be*(0.32) (GO70). See also (GO73H) and ¹²B.

6. 11Li(β-)11Be

Qm = 20.7

See ¹¹Li.

7. 11B(n, p)11Be

Qm = -10.726

See (FL67E) and ¹²B.

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

Qm = -12.208

See (BA74C).