A=9Be (1979AJ01)

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⁹Be (1979AJ01)

(See Energy Level Diagrams for ⁹Be)

GENERAL: See also (1974AJ01) and Table 9.2 [Table of Energy Levels] (in PDF or PS).

Shell model: (1975KU27, 1975SC1K, 1977CA08, 1977JA14, 1978BO31).

α and cluster models: (1974CH19, 1974GR42, 1974PA1B, 1975AB1E, 1975CH28, 1975KR1D, 1975RO1B, 1975SC1K, 1976ZA06, 1977DE1K, 1977HO1F, 1977OK01, 1977SE1D, 1978FO1J, 1978FO1G, 1978HO1E, 1978OK01, 1978OS01).

Collective and deformed models: (1974BO25, 1976BR26, 1977CA08).

Special levels: (1974IR04, 1974KU06, 1975CH28, 1975LI20, 1975WI1E, 1976IR1B, 1976ZA06, 1977CA08, 1977JA14, 1978BO31, 1978FO1G, 1978HO1E, 1978OK01, 1978OK1B).

Electromagnetic transitions: (1974CH46, 1974HA1C, 1974KU06, 1974MU13, 1976KU07, 1977DO06, 1978KI08).

Astrophysical questions: (1973CA1B, 1973SC1C, 1973SC1D, 1973TI1A, 1973TR1B, 1973WE1D, 1974AU1A, 1974BO1J, 1974BO1K, 1974RE1A, 1974RO1G, 1975CH1F, 1975LA1E, 1975ME1E, 1975PR1B, 1976AU1B, 1976AU1C, 1976BO1E, 1976BO1H, 1976BO1J, 1976CO1B, 1976EP1A, 1976FU1B, 1976GI1C, 1976HA1F, 1976PE1A, 1976RA1C, 1976RO1J, 1976RO12, 1976SI1C, 1976SI1D, 1976VI1A, 1977AU1B, 1977BO1F, 1977DR1C, 1977DW1A, 1977GA1C, 1977HA1L, 1977MA1H, 1977PR1D, 1977SC1D, 1977WE1D, 1978AU1C, 1978BY1A, 1978DW1A).

Special reactions: (1975AR14, 1975FE1A, 1975KU01, 1975RA12, 1975RA14, 1975RA21, 1975ZE01, 1976BE1K, 1976BU16, 1976CH28, 1976FR05, 1976HI05, 1976LE1F, 1976MI13, 1976NA11, 1976OS04, 1976RA1C, 1976RO12, 1977AR06, 1977FE1B, 1977GE08, 1977GO07, 1977GR1D, 1977KU1D, 1977PR05, 1977ST34, 1977ST1G, 1977YA1B, 1978BA1J, 1978BI08, 1978DI04, 1978FA1D, 1978GE1C, 1978GR1F, 1978UN01, 1978WE1D).

Muon and neutrino capture and reactions: (1974EN10, 1975CA1H, 1975CH22, 1975FE1B, 1975KN1C, 1976SH1H, 1977CA1E, 1977DO06, 1977MU1A, 1978DE15, 1978LE04).

Pion capture and reactions: (1973AL1A, 1973AR1B, 1973BA1G, 1973GO41, 1973WI1A, 1974AM01, 1974CL04, 1974DI20, 1974GO04, 1974HU14, 1974KA07, 1974MI06, 1974SP1A, 1974ST1G, 1974TA18, 1975BA1L, 1975BA1G, 1975BU1A, 1975ER03, 1975HU1D, 1975NI1B, 1975RO1G, 1975TA1C, 1975VO1D, 1975YA02, 1976AB1B, 1976AL1F, 1976AS1B, 1976BA1P, 1976DO1D, 1976DU1B, 1976ED1A, 1976EN02, 1976HEZU, 1976KI1E, 1976PI1B, 1976RA1F, 1976TR1A, 1977AB09, 1977AL1C, 1977AN1D, 1977AP1A, 1977AR1F, 1977AS1D, 1977BA51, 1977BA1Q, 1977BA2D, 1977BE1V, 1977DE1F, 1977DE1G, 1977DE1H, 1977DE1J, 1977DO06, 1977FY1A, 1977HO1B, 1977MA35, 1977MC1E, 1977PI1C, 1977SC1F, 1977SH1C, 1977SP1B, 1977TE1A, 1978BA1L, 1978BO01, 1978ER1C, 1978GEZX, 1978KI08, 1978MI1D, 1978MO01, 1978OL1A, 1978SE1D, 1978TH1B, 1978ZE01).

Kaon reactions and reactions involving other mesons: (1973GO41, 1975PO1C, 1976AB1B, 1976BO1K, 1976BR1G, 1976KI1E, 1977AN1D, 1977BA27, 1977BE1U, 1977PO1A, 1978AT01, 1978BR1G).

Other topics: (1973DZ1A, 1974CH19, 1974IR04, 1974KU06, 1974MU13, 1975CH1E, 1975CH28, 1975KU27, 1975LI20, 1975SC1M, 1976BR26, 1976DA1D, 1976DA1E, 1976ES1A, 1976GA1C, 1976IR1B, 1976KU07, 1976MA04, 1977KO1K, 1977PO1A, 1978OS01).

Ground state properties: (1974DE1E, 1974EN10, 1974KU06, 1974MU13, 1974PA1B, 1974SHYR, 1975BE31, 1975CH28, 1976BR26, 1976FU06, 1977BA2E, 1977MA35, 1977OK01, 1978AN07).

μ = -1.1778 ± 0.0009 nm (1976WE17);

Q = +53 ± 3 mb (1978SHZM).

The neutron spectroscopic factor of ⁹Be is 0.42 ± 0.04 (1977LA11).

1. (a) ⁶Li(t, n)⁸Be Q_m = 16.0240 E_b = 17.6892
(b) ⁶Li(t, p)⁸Li Q_m = 0.801
(c) ⁶Li(t, d)⁷Li Q_m = 0.993
(d) ⁶Li(t, α)⁵He Q_m = 15.22
(e) ⁶Li(t, n)⁴He⁴He Q_m = 16.1159

The 0° differential cross section for reaction (a) increases monotonically between E_t = 0.10 and 2.4 MeV (1960SE12, 1961VA43, 1962SE1A) except for a resonance at E_t = 1.875 MeV (⁹Be* = 18.938). The excitation function for ⁸Li (reaction (b)) increases monotonically for E_t = 0.275 to 1.000 MeV (1972CI05, 1972CI1C). In the range E_t = 2.0 to 6.8 MeV, a broad peak [Γ ≈ 1.3 MeV] is observed at E_t = 4.57 MeV [E_x = 20.73 MeV] (1973AB10). For reaction (c), (d) and (e) see (1966LA04). See also ⁸Li and (1977SU1A).

2. ⁶Li(α, p)⁹Be Q_m = -2.1248

Angular distributions of p₀ have been measured at E_α = 10.2 to 14.7 MeV and at 30 MeV: see (1974AJ01). In a study of the inverse reaction [⁹Be(p, α)⁶Li] at 45 MeV, the spectroscopic factors for (⁶Li + t) and (⁵He + α) cluster structures in ⁹Be are calculated to be 0.003 and 0.102, respectively (1972DE01, 1972DE02).

3. ⁷Li(d, γ)⁹Be Q_m = 16.6960

For E_d = 0.1 to 1.1 MeV, a resonance in the yield of capture γ-rays is observed at E_d = 362 ± 3 keV (1965WO01), 361 ± 2 keV (1965IM01), corresponding to ⁹Be*(16.976) with Γ_c.m. < 0.47 keV. The small width of this state and its energy correspondence with ⁹Li*(2.69) argue for T = 3/2 (1965WO01). The angular distribution of the γ-rays to ⁹Be(0) is isotropic to within 7% (1965IM01). The branching ratios to ⁹Be*(0, 1.7, 2.4, 2.8, 3.1, 4.7) are 100 / 11.8 ± 0.6 / 3.3 ± 0.7 / 13.3 ± 4.2 / - / 12.9 ± 1.3 (1971SC19). The E_x and Γ of ⁹Be*(2.8, 4.7) are 2.82 and 1.7 MeV, and 4.64 and 0.95 MeV, respectively. The character of the decay suggests (1/2)^- for the second T = 3/2 state [⁹Be*(16.98)] and is consistent with J^π = (1/2)^- for ⁹Be*(2.8) (1971SC19).

4. (a) ⁷Li(d, n)⁸Be Q_m = 15.031 E_b = 16.6960
(b) ⁷Li(d, α)⁵He Q_m = 14.23
(c) ⁷Li(d, n)⁴He⁴He Q_m = 15.123

The yield of neutrons has been measured for E_d = 0.2 to 19 MeV [see (1974AJ01)] and for 0.4 to 3.0 MeV (1975MC02; σ_t), 2.5 MeV (1974JO1C) and 14.8, 18 and 23 MeV (1977LO10). Resonances in the yield of neutrons are reported at E_d = 0.36, 0.68, 0.98 and (1.8) MeV: see Table 9.3 (in PDF or PS). Polarization measurements have been reported at E_d = 0.64 MeV and at 2.5 to 3.7 MeV: see (1974AJ01). See also (1975SE07, 1977SE09).

The yield of α-particles has been studied for E_d = 0.2 to 3.0 MeV [see (1974AJ01)] and at E_d = 0.60 to 1.25 MeV (1973RO42: α₁). Resonances are observed at E_d = 0.75, 1.00 and 2.5 MeV: see Table 9.3 (in PDF or PS).

At E_d = 1.0 MeV reaction (c) is dominated by sequential decay via ⁸Be*(2.9) and ⁵He_g.s.. There is evidence also for the involvement of ⁹Be*(17.50): J = 3/2 is suggested (1973HE26). See also (1975DA15, 1978SP03). See also ⁵He, ⁸Be, (1975FO19; astrophysics) and (1974JO1C, 1975GO38, 1977GR1F, 1977LO10, 1977SA28; applications).

5. ⁷Li(d, p)⁸Li Q_m = -0.192 E_b = 16.6960

The yield of p₀ has been measured for E_d = 0.29 to 0.78 MeV and the ⁸Li yield for E_d = 0.4 to 7.0 MeV [see (1974AJ01)] and from threshold to 3.6 MeV (1974MCZS, 1975MC02: σ_t; also cross sections for p₀ and p₁, from 0.5 MeV). The yield of ⁸Li has also been measured for E_d = 0.61 to 1.95 MeV (1976SC14): resonances are displayed in Table 9.3 (in PDF or PS). The total cross section at the E_d = 0.77 MeV resonance is 181 ± 8 mb (1976SC14). For earlier values see (1974AJ01). The cross section at the 0.77 MeV resonance serves as normalization for the ⁷Be(p, γ)⁸B data and to calculations of the S-factor, of interest in relation to the solar neutrino problem. See also (1976HA1J).

6. ⁷Li(d, d)⁷Li E_b = 16.6960

The elastic scattering [E_d = 0.4 to 1.8 MeV] shows a marked increase in cross section for E_d = 0.8 to 1.0 MeV (perhaps related to ⁹Be*(17.30)) and a conspicuous anomaly at E_d = 1.0 MeV, due to p-wave deuterons [⁹Be*(17.50)]. The elastic scattering has also been studied for E_d = 1.0 to 2.6 MeV (1974LO10) and E_d = 10.0 to 12.0 MeV (1971BI11). See also ⁷Li.

7. (a) ⁷Li(d, t)⁶Li Q_m = -0.993 E_b = 16.6960
(b) ⁷Li(d, ³He)⁶He Q_m = -4.482

The cross section for reaction (a) rises steeply from threshold to 95 mb at E_d = 2.4 MeV and then more slowly to ≈ 165 mb at E_d = 4.1 MeV (1955MA20). The t₀ yield curve (θ_lab = 155°) decreases monotonically for E_d = 10.0 to 12.0 MeV (1971ZA07). See also ⁶Li. For reaction (b) see ⁶He.

8. ⁷Li(t, n)⁹Be Q_m = 10.4387

See (1974AJ01) and ¹⁰Be.

9. (a) ⁷Li(³He, p)⁹Be Q_m = 11.2025
(b) ⁷Li(³He, np)⁸Be Q_m = 9.537

Observed proton groups are listed in Table 9.4 (in PDF or PS). The parameters for the particle and γ-decay of observed states are displayed in Table 9.5 (in PDF or PS), and in Table 9.6 (in PDF or PS) (1976MC10). Angular distributions have been reported in the range E(³He) = 0.9 to 10 MeV [see (1974AJ01)], at 1.0 to 2.5 MeV (1975BO55: p₀, p₂) and at 14 MeV (1976IR02: p₀). See also ¹⁰B and (1973WE15, 1975ST16; theor.).

10. ⁷Li(α, d)⁹Be Q_m = -7.1507

At E_α = 30 MeV d₀, d₁ and d₂ angular distributions have been measured (1972ME07). See also (1976LE1K).

11. ⁷Li(⁶Li, α)⁹Be Q_m = 15.223

Angular distributions of the α₀ group have been measured at E(⁷Li) = 3.78 to 5.95 MeV (1967KI03). See also (1974AJ01).

12. ⁷Li(¹¹B, ⁸Be)⁹Be Q_m = 7.286

Not reported: see (1970LK1A; theor.).

13. ⁹Li(β^-)⁹Be Q_m = 13.607

⁹Li decays by β^- emission with τ_1/2 = 178.3 ± 0.4 msec to ⁹Be*(0, 2.43, 2.78): see reaction 1 in ⁹Li, and Table 9.7 (in PDF or PS). ⁹Be(2.43, 2.78) are neutron unstable. The probability that ⁹Li decays to these two states is 0.35. The branching ratio for the ⁹Be*(2.43) → ⁸Be(0) + n decay is (6.4 ± 1.2)%. ⁹Be*(2.78) decays mainly to ⁸Be(0) + n. The assignment J^π = 1/2^- to ⁹Be*(2.78) derives from the nature of the ⁹Li decay, and the large value of θ²_p [0.48 ± 0.06] which is in agreement with the shell model prediction that the 1/2^- state should decay mainly by p-wave neutron emission to ⁸Be(0): if J^π = 3/2^- this decay branch should be small (1970CH07).

14. (a) ⁹Be(γ, n)⁸Be Q_m = -1.6652
(b) ⁹Be(γ, α)⁵He Q_m = -2.47
(c) ⁹Be(γ, n)⁴He⁴He Q_m = -1.5733
(d) ⁹Be(γ, 2n)⁷Be Q_m = -20.565

The photoneutron cross section has been measured from threshold to 320 MeV: see Table 9.6 (in PDF or PS) in (1966LA04) and (1974KN08, 1975KN03: 17 to 37 MeV; monoenergetic γ), (1973AN29, 1975HU03, 1977BU02, 1978BU01). A sharp peak occurs 6 keV above threshold (1967BE49) [but see discussion in (1968BA1C)] with σ_max = 1.6 mb. The cross section then decreases slowly to 1.2 mb at E_γ = 40 keV (1967BE49). From bremsstrahlung studies, peaks in the (γ, Tn) cross section are observed corresponding to E_x = 1.80 and 3.03 MeV (1975HU03) [see both (1973AN29, 1975HU03) for additional structures]. At higher energies, using monoenergetic photons, (1975KN03) [who also report (γ, n) + (γ, pn) and (γ, 2n)] find the (γ, Tn) cross section to be relatively smooth from E_γ = 17 to 37 MeV with weak structures which correspond to E_x = 17.1, 18.8, 19.9, 21.4, 22.4, 23.8 [ ± 0.2] MeV and 27 ± 0.5 MeV (broad). See also (1976BE1H).

In the range E_γ = 18 to 26 MeV the integrated (γ, n₀) cross section is < 0.1 MeV · mb, that for (γ, n₁) = 2.4 ± 0.4 MeV · mb (1977BU02) and the combined integrated cross section for (γ, n) to ⁸Be*(16.6) and (γ, α₀) to ⁵He_g.s. is 13.1 ± 2 MeV · mb (1978BU01).

The total absorption cross section has been measured for E_γ = 10 to 210 MeV: it rises to ≈ 5 mb at ≈ 21 MeV, decreases to about 0 at 160 MeV and then increases to ≈ 1.5 mb at 210 MeV (1974AH03, 1975AH06). (1969DO09) report an integrated cross section of 156 ± 15 MeV · mb for E_γ = 10 to 29 MeV and resonant structure at E_γ = 11.8, (13.5), 14.8, (17.3), (19.5), 21.0, (23.0) and (25.0) MeV (1969DO09). Fine structure is reported at E_γ = 20.47 ± 0.04 and 20.73 ± 0.04 MeV (1964TE04). The absorption coefficient of 6.418 MeV γ-rays is reported by (1975MO27). Double pair production by 6.6 MeV γ-rays has been observed by (1976RO1N): σ_ππ/σ_π = (1.8 ± 0.6) × 10^-5 [average of values from interaction with several different nuclei]. See also (1973VE12, 1975SC05), (1974BU1A, 1975AB1F, 1975BR1F, 1977DA1B), (1975FO19; astrophysics) and (1976KH1C, 1978OC1B, 1978OK1B; theor.).

15. (a) ⁹Be(γ, p)⁸Li Q_m = -16.888
(b) ⁹Be(γ, np)⁷Li Q_m = -18.921

The yield shows structure in the energy region corresponding to the ⁹Be levels at 17 - 19 MeV (1962CL06) followed by the giant resonance at E_γ ≈ 23 MeV (1962CL06; σ = 2.64 ± 0.30 mb). (1966DE13) report structure attributed to eleven states of ⁹Be with 18.2 < E_x < 32.2 MeV. Integrated cross sections have been obtained for each of these resonances, and over different energy intervals for protons leading to ⁸Li*(0 + 0.98, 2.26 + 3.21, 9.0, 17.0) (1966DE13). Angular and energy distributions of photoprotons in various energy intervals have been studied by many groups: see (1974AJ01) and (1974GO04). See also (1974DO07, 1975MA1K, 1978DO02) and (1975AN1H; theor.).

16. (a) ⁹Be(γ, d)⁷Li Q_m = -16.6960
(b) ⁹Be(γ, t)⁶Li Q_m = -17.6892

The integrated cross sections are reported to be 1.0 ± 0.5 MeV · mb (E_γ = 21 → 33 MeV) for reaction (a) to ⁷Li*(0 + 0.4) and 0.6 ± 0.3 MeV · mb (E_γ = 25 → 33 MeV) for reaction (b) to ⁶Li(0). The total integrated cross section for [(γ, p) + (γ, pn) + (γ, d) + (γ, t)] is given as 33 ± 3 MeV · mb by (1966DE13), who also report resonances in the (γ, d) and (γ, t) cross sections corresponding to ⁹Be*(26.0 ± 0.2) and ⁹Be*(32.2 ± 0.3), respectively. See also (1974AJ01).

17. ⁹Be(γ, γ)⁹Be

See (1977CR1C) and (1974AJ01).

18. (a) ⁹Be(e, e)⁹Be
(b) ⁹Be(e, en)⁸Be Q_m = -1.6652
(c) ⁹Be(e, ep)⁸Li Q_m = -16.888
(d) ⁹Be(e, eα)⁵He Q_m = -2.47
(e) ⁹Be(e, eπ⁺)⁹Li Q_m = -153.174

< r² >^1/2 = 2.46 ± 0.11 fm, Q = 6.5_-0.6^+0.9 fm², b = 1.5_-0.2^+0.3 fm [b = oscillator parameter] (1973BE19);

< r² >^1/2 = 2.519 ± 0.012 fm, Q = 6.4 ± 2.4 fm² (1972JA10) and private communication to J.C. Bergstrom);

< r² >^1/2_M = 3.2 ± 0.3 fm; Ω = 6 ± 2 μ_N · fm² [this value of the magnetic octupole moment implies a deformation of the average nuclear potential] (1975LA23; see also for calculations of (b)).

The elastic scattering of electrons has been studied for E_e up to 700 MeV: see (1974AJ01). Magnetic elastic scattering gives indications of both M1 and M3 contributions (1965GR18, 1966RA29). See also (1973FE13).

Inelastic scattering populates a number of levels: Table 9.8 (in PDF or PS) displays the parameters of the states. See also (1974TI05, 1975DI05). Electron bremsstrahlung has been measured at E_e = 1.0 and 2.0 MeV by (1968RE11). For reaction (b) see (1974AJ01). At E_e = 700 MeV the proton separation spectra are similar to those observed in (p, 2p) except for an upward shift in the excitation (1978NA05). See also (1977BE1Q, 1977TU1C: E_e = 500 MeV; observe a peak at E_x ≈ 25 MeV), (1973KU19: 1.184 GeV) and (1974AJ01). For reaction (d) see (1975GE12). For reaction (e) see (1977SH1C). See also (1974DE1E, 1975FA1A) and (1973GA19, 1973KE1B, 1974BE10, 1974KU06, 1975AB1E, 1976DU05, 1977KU12, 1977OK01, 1977OK1A, 1978OK01; theor.).

19. (a) ⁹Be(n, n)⁹Be
(b) ⁹Be(n, 2n)⁸Be Q_m = -1.6652
(c) ⁹Be(n, nd)⁷Li Q_m = -16.6960

Population of ⁹Be*(0, 1.7, 2.4, 3.1) and possibly ⁹Be*(6.8) has been reported in this reaction: see (1974AJ01). For the neutron decay of these states see Table 9.5 (in PDF or PS). Angular distributions have been reported at E_n = 14 MeV [see (1974AJ01)], at 5.9, 10.1 and 14.2 MeV (1977DR09: n₀, n_1+2+3+4), and 14.1 MeV (1974HY01: n₀, n₂). See also (1974HO1E, 1975HO1F, 1976BI1B). For reactions (a) and (b) see also ¹⁰Be. For reaction (c) see (1978RI02). See also (1976MC1E) and (1978BY1B, 1978BY1C; theor.).

20. ⁹Be(p, p)⁹Be

Elastic and inelastic scattering angular distributions have been studied at many energies for E_p = 5 to 1000 MeV [see (1974AJ01)] and (1974YA1C: p₀(5.0, 6.0 MeV), p₁(5.2, 6.0 MeV), p₂(4.2 → 6.0 MeV)), (1977CO1G: p₀(35.2 MeV)) and (1976AL1G: p₀; 1 GeV). The elastic angular distributions show pronounced diffraction maxima characteristic of the optical model. See (1973MO01) for a discussion of optical model parameters. (1973VO02), in a coupled channels analysis, find that a quadrupole-deformed optical model potential with a deformation parameter β = 1.1 provides an improved description of the elastic data and a good fit to the p₂ data.

The structure corresponding to ⁹Be*(1.7) is asymmetric: the line shape peaks 25⁺¹⁵_-11 keV above the threshold for ⁸Be + n (1970TU06). The population of ⁹Be*(1.7) has been studied for E_p = 4.2 to 5.5 MeV: it is consistent with a scattering length of about -20 fm between a neutron and ⁸Be. An anomaly at E_p = 5.1 MeV is attributed to FSI between n, p and ⁸Be (1974YA05).

The weighted mean of the values of E_x listed in (1974AJ01) is 2432 ± 3 keV. ⁹Be*(3.1) has a width 250 ± 50 keV (1960SP08), J^π = 3/2⁺, 5/2⁺, E_x = 3.03 ± 0.03 MeV (1956BO18), 3.04 ± 0.05 MeV (1960SP08). Higher states are observed at E_x = 4.8 ± 0.2, 6.76 ± 0.06 [J^π = 1/2⁺, 5/2⁺, 7/2⁺ (but see below), Γ = 1.2 ± 0.2 MeV], 7.94 ± 0.08 (Γ ≈ 1 MeV), 11.3 ± 0.2 MeV (Γ ≈ 1 MeV), 14.4 ± 0.3 (Γ ≈ 1 MeV), 16.7 ± 0.3, 17.4 ± 0.3, 19.0 ± 0.4, 21.1 ± 0.5 and 22.4 ± 0.7 MeV [the five highest states are all broad] (1965HA17). (1965JA1A) reports for ⁹Be*(2.4, 6.8) B(E2↑) = 49 ± 6 and 24 ± 4 fm⁴ and Γ(E2↓) = 0.0025 and 0.10 eV, respectively. The strong population of ⁹Be*(2.4, 6.8) is consistent with the assumption that they have J^π = 5/2^- and 7/2^-, respectively, and are members of the ground state K = 3/2^- band. See also (1966LA04).

(1974BI14) have studied the elastic scattering at E_p = 25 MeV: a non-zero D (depolarization) is reported; its existence constitutes evidence of a nucleon-nucleus spin-spin interaction. On the other hand (1976MOZF: E_p-bar = 32 MeV) find no evidence for a non-zero value of D in the transition to ⁹Be*(2.4). See also (1977KI04, 1978FR1D), (1974LO1B), (1973WE15, 1974GU13, 1974GU1D, 1974JA1F, 1978BY1B, 1978BY1C, 1978WO13; theor.) and ¹⁰B.

21. (a) ⁹Be(p, 2p)⁸Li Q_m = -16.888
(b) ⁹Be(p, pd)⁷Li Q_m = -16.6960
(c) ⁹Be(p, pα)⁵He Q_m = -2.47
(d) ⁹Be(p, pn)⁸Be Q_m = -1.6652
(e) ⁹Be(p, p³He)⁶He Q_m = -21.177
(f) ⁹Be(p, d³He)⁵He Q_m = -20.82

The summed proton spectrum (reaction (a)) shows two peaks with Q = -16.4 ± 0.3 and -25.4 ± 0.5 MeV, corresponding to removal of a p-proton and an s-proton respectively, and a third peak of uncertain assignment (perhaps due to unresolved states) with Q = -32.3 ± 0.6 MeV (1966TY01: E_p = 460 MeV). See also ⁸Li and (1973MA67; theor.). For reaction (b) see (1974AJ01). Quasi-free scattering of the incident protons by zero-momentum α-particle clusters is consistent with the data obtained at E_p = 26.0, 35.0, 46.8 and 57 MeV (1968RO19, 1972QU01). At E_p = 100 MeV (1977CO07, 1977RO02) find < S_α > = 0.45 ± 0.02 using DWIA analysis: this value is consistent with that predicted by a simple LS coupling shell model calculation. See also (1975RO1B, 1978CH1H) and (1975SA01; theor.).

At E_p = 12.7 MeV, ⁹Be*(3.05) is strongly populated and ⁹Be*(4.70) is also observed in reaction (d) (1977JE01). See also Table 9.5 (in PDF or PS). (1978CH07), ⁸Be (1977WA05; E_p = 45 and 47 MeV), (1974MI05, 1974YA05) and (1974AV02; theor.). See also (1974AJ01). In reaction (f), at E_p = 100 MeV, (1977CO07) find < S_α > = 0.47 ± 0.04.

22. ⁹Be(d, d)⁹Be

Elastic angular distributions have been studied in the range 1.1 to 410 MeV [see (1974AJ01)] and at E_d = 1.0 to 2.2 MeV (1972LO05), E_d-bar = 15 MeV (1976DA15; also d₂, d₄) and E_d = 27.98 MeV (1977OO01). Angular distributions to ⁹Be*(2.4) have also been reported at E_d = 11.8, 14.35 and 15.8 MeV: see (1974AJ01).

Inelastic groups have been reported to ⁹Be*(1.7, 2.4, 3.1, 4.7, 6.8): see (1966LA04). (1968KR02) report E_x = 2431.9 ± 7.0 keV and 3040 ± 15 keV (Γ = 294 ± 20 keV). See also (1978LO1C), (1977TE1A) and (1974BO39, 1974CH58, 1974GU1D, 1977DM1A; theor.).

23. (a) ⁹Be(t, t)⁹Be
(b) ⁹Be(t, nt)⁸Be Q_m = -1.6652

The angular distribution of elastically scattered tritons has been measured at E_t = 2.10 MeV (1969HE08, 1970CO04). Reaction (b) at E_t = 4.2 and 4.6 MeV proceeds via ⁹Be*(2.4) (1967SE11).

24. (a) ⁹Be(³He, ³He)⁹Be
(b) ⁹Be(³He, 2α)⁴He Q_m = 19.0045

Angular distributions of elastically scattered ³He particles have been obtained at E(³He) = 4 to 32.3 MeV [see (1974AJ01)], at E(³He) = 1.6 to 2.4 MeV (1974BO38) and 32.6 MeV (1975BU11; polarized ³He). See also (1975DA1A). At E(³He) = 217 MeV (1973WI07, 1976WI05) angular distributions have been studied to ⁹Be*(0, 2.4). For optical model parameters see discussions in (1972BU30, 1973WI07, 1976WI05). At E(³He) = 39.8 MeV inelastic ³He groups are observed to ⁹Be*(1.7, 2.4, 3.1, 4.7, 6.8, 14.4) (1969BA06). See also (1976RO1L). In a study of reaction (b) the (⁵He + α) system is found to be mainly in an S-state: the probability of finding such a cluster in ⁹Be is N_eff = 0.05 (1975KA05). See also ⁸Be.

25. (a) ⁹Be(α, α)⁹Be
(b) ⁹Be(α, 2α)⁵He Q_m = -2.47
(c) ⁹Be(α, αn)⁸Be Q_m = -1.6652

Elastic scattering has been studied at many energies for E_α = 8.76 to 104 MeV [see (1974AJ01)] and at 5.00 to 5.50 MeV (1973GO15). See (1972DE01, 1972DE02) for a discussion of optical model parameters. The structure (⁵He + α) for ⁹Be is found to be much more probable than (⁶Li + t): the ratio of spectroscopic factors is about 30 (1972DE01, 1972DE02) .

Inelastic groups have been observed to ⁹Be*(1.7, 2.4, 3.1, 6.8, 11.3): see (1966LA04). The angular distribution of the α₁ group to ⁹Be*(1.7) is consistent with J^π = 1/2⁺ (1964LU02: E_α = 18.4 MeV). The angular distributions for α₂ are consistent with l = 2 [J^π = (1/2, 5/2, 7/2)^-] (1958SU14, 1967FU08). Analysis based on the rotational model leads to a deformation coefficient β₂ = 0.34 ± 0.01 (1964GR39).

The summed α-spectra from reaction (b) show a peak corresponding to quasi-elastic scattering leaving ⁵He in its ground state. The angular distribution peaks at the angle corresponding to zero-momentum α-cluster. The probability of formation of such clusters is (7⁺¹³_-5)% (1969PI11). See also (1977WA1M). (1976WO11) find S_α = 0.96.

A study of continuum neutrons at E_α = 4.9 to 6.4 MeV (reaction (c)) indicates that sequential decay takes place via ⁹Be*(1.7, 2.4, 3.1) (1972OB01). See also (1974AJ01, 1975RO1B) and (1974CH58, 1974KU15, 1974LO09, 1974PI11, 1976AV05, 1977DE1K, 1977DM1A, 1977MO11; theor.).

26. (a) ⁹Be(⁶Li, ⁶Li)⁹Be
(b) ⁹Be(⁷Li, ⁷Li)⁹Be

Elastic angular distributions have been measured at E(⁶Li) = 4 and 6 MeV (1974VO06) and 24 MeV (1968DA20) and at E(⁷Li) = 24 MeV (1972WE08) and 34 MeV (1977KE09).

27. ⁹Be(⁹Be, ⁹Be)⁹Be

Elastic angular distributions have been obtained at E = 5, 9, 12 and 16 MeV (1977YO02).

28. ⁹Be(¹²C, ¹²C)⁹Be

Elastic angular distributions are reported at E(¹²C) = 12, 15, 18 and 21 MeV (1970BA49) and E(⁹Be) = 14, 20 and 26 MeV (1978LA1G) and 43 MeV (1977MA1L). The neutron spectroscopic factor for ⁹Be is 0.84 (1970BA49). For spallation studies see (1977IG1D, 1978CH02). See also (1976ECZZ, 1977PE1B, 1978MA1L), (1978EN06) and (1978PA1B; theor.).

29. ⁹Be(¹⁴N, ¹⁴N)⁹Be

Elastic angular distributions have been measured at E(¹⁴N) = 25 (1966OE1A) and 27.3 MeV (1959HA28).

30. (a) ⁹Be(¹⁶O, ¹⁶O)⁹Be
(b) ⁹Be(¹⁸O, ¹⁸O)⁹Be

Elastic angular distributions have been reported at E(¹⁶O) = 15, 18, 21.5 and 25 MeV (1970BA49), 25.7 to 29.5 MeV (1975FU05) and 30 MeV (1969KR03), and at E(¹⁸O) = 12.1, 16 and 20 MeV (1971KN05). See also (1974TA1C, 1978CH02), (1978EN06) and (1978PA1B; theor.).

31. (a) ⁹Be(²⁴Mg, ²⁴Mg)⁹Be
(b) ⁹Be(²⁷Al, ²⁷Al)⁹Be
(c) ⁹Be(²⁸Si, ²⁸Si)⁹Be

Elastic angular distributions have been measured at E(⁹Be) = 14, 20 and 26 MeV for reactions (a), (b) and (c) (1977BA71) and at 14 and 17 MeV for reaction (c) (1977EC04). See also (1978DE1M) and (1978EN06).

32. ¹⁰Be(d, t)⁹Be Q_m = -0.5545

Forward angular distributions have been obtained at E_d = 15.0 MeV for the tritons to ⁹Be*(0, 1.7, 2.4, 3.1). The ground state transition is well fitted by l = 1. The transition to ⁹Be*(1.7) [Γ ≈ 165 ± 25 keV] is consistent with J^π = 1/2⁺, that to ⁹Be*(2.4) is quite well fitted with l = 3 [J^π = 5/2^-], and that to ⁹Be*(3.1) [Γ = 280 ± 25 keV] is consistent with l = 2. No other narrow states are seen up to E_x = 5.5 MeV (1970AU02).

33. (a) ¹⁰B(γ, p)⁹Be Q_m = -6.5853
(b) ¹⁰B(e, ep)⁹Be Q_m = -6.5853

See reactions 24 and 26 in¹⁰B.

34. ¹⁰B(n, d)⁹Be Q_m = -4.3607

A good fit to the angular distributions of the deuterons to ⁹Be*(0, 2.4) has been obtained at E_n = 14.4 MeV, using DWBA. The spectroscopic factors are in close agreement with shell model predictions (1965VA05). See also ¹¹B in (1980AJ01).

35. ¹⁰B(p, 2p)⁹Be Q_m = -6.5863

The summed proton spectrum at E_p = 460 MeV yields Q = -6.7 ± 0.5, -11.9 ± 0.5, -17.1 ± 0.6 (all l ≠ 0) and Q = -30.5 ± 0.6 MeV (l = 0) (1966TY01). See also ¹⁰B.

36. ¹⁰B(d, ³He)⁹Be Q_m = -1.0918

Angular distributions of the ³He groups corresponding to ⁹Be*(0, 2.4) have previously been measured at E_d = 11.8 and 28 MeV: see (1974AJ01). Recent angular distribution measurements at E_d-bar = 15 MeV (1974LU06; to ⁹Be*(0, 2.4)) and at E_d = 52 MeV (1975SC41; to ⁹Be*(0, 2.4, 6.7)) lead to S = 0.72 and 0.82 (1974LU06) and relative S = 1.00, 0.98 and 0.58 (1975SC41). In the latter experiment ⁹Be*(11.3) appears also to be strongly populated. The data for ⁹Be*(0, 2.4) are very similar, as predicted, to those obtained in the mirror reaction: see reaction 12 in ⁹B. See also (1974DA1D; theor.) and ¹²C in (1980AJ01).

37. ¹⁰B(t, α)⁹Be Q_m = 13.2287

At E_t = 12.9 MeV α-groups are observed to the ground state of ⁹Be and to excited states at E_x = 1.75 ± 0.03, 2.43, 3.02 ± 0.04 (Γ = 320 ± 60 keV), 11.27 ± 0.04 (Γ = 530 ± 70 keV), (14.4) [Γ ≈ 800 keV], 14.39 and 16.67 MeV. The T = 3/2 state ⁹Be*(14.39) is very weakly populated [≈ 5% of intensity of α₂]. The angular distribution of the α₂ group shows sharp forward and backward peaking. The α₀ group is not peaked in the backward direction (1968AJ01). A study at E_t = 1.0 to 3.2 MeV finds E_x = 1.750 ± 0.025 MeV, Γ = 220 ± 8 keV. The angular distribution of the corresponding α-group has been determined at E_t = 2.5 MeV (1971GE09). See also (1977CI1A) and ¹³C in (1981AJ01).

38. ¹⁰B(⁷Li, ⁸Be)⁹Be Q_m = 10.670

See (1977KO27).

39. ¹⁰B(¹⁴N, ¹⁵O)⁹Be Q_m = 0.712

The ground state angular distribution has been measured at E(¹⁴N) = 27.5 MeV (1962NE01).

40. ¹⁰B(¹⁶O, ¹⁷F)⁹Be Q_m = -5.985

See (1968OK06).

41. ¹¹B(n, t)⁹Be Q_m = -9.5586

The angular distribution of t₀ has been measured at E_n = 14.4 MeV (1970MI14).

42. (a) ¹¹B(p, ³He)⁹Be Q_m = -10.3224
(b) ¹¹B(p, pd)⁹Be Q_m = -15.8159

At E_p = 45 MeV angular distributions are reported for the ³He ions corresponding to ⁹Be*(0, 2.4, 11.8, 13.8, 14.39 [T = 3/2], 15.96 ± 0.04 [T = 1/2]). In addition one or more states may be located at ⁹Be*(15.13). It is suggested that ⁹Be*(11.8, 13.8, 15.96) are the J^π = 3/2^-, T = 1/2 analogs to ⁹B*(12.06, 14.01, 16.02) (1971HA10). Angular distributions are also reported at E_p = 40 MeV (1971KA21: α₀, α₂). The intensity of the group to ⁹Be*(3.1) is ≈ 1% of the ground state group (1971KA21). The excitation energy of the first T = 3/2 state is E_x = 14392.6 ± 1.8 keV (1974KA15) using the (1977WA08) mass for ⁹Be_g.s.. For reaction (b) see (1964BA1C).

43. (a) ¹¹B(d, α)⁹Be Q_m = 8.0308
(b) ¹¹B(d, nα)⁴He⁴He Q_m = 6.4575

Alpha groups are reported corresponding to ⁹Be*(0, 1.7, 2.4, 3.1). The width of ⁹Be*(1.7) [E_x = 1.70 ± 0.01 MeV (1975FO13)] is Γ_c.m. = 224 ± 25 (1958KA31, 1966PU02), 200 ± 10 keV (1975FO13). The weighted mean of the values of E_x of ⁹Be*(2.4), reported in (1974AJ01), is 2425 ± 3 keV. The 5/2⁺ state is at E_x = 3.02 ± 0.03 MeV (1955LE36), 3.05 ± 0.03 MeV (1956BO18): Γ_c.m. = 257 ± 25 keV (1958KA31, 1966PU02). The ratio Γ_γ/Γ of ⁹Be*(1.7) ≤ 2.4 × 10^-5, that for ⁹Be*(2.4) is (1.16 ± 0.14) × 10^-4 (1966PU02). Since Γ_γ is known from (e, e') [see Table 9.8 (in PDF or PS): 0.089 ± 0.010 eV], Γ = 0.77 ± 0.15 keV.

Angular distributions for α₀ and α₂ are reported at E_d = 0.39 to 2.5 MeV and at 12 MeV [see (1974AJ01)] and at 3.0 to 3.9 MeV (1974CA34, 1975CA1J, 1975CA1K). Reaction (b), at E_d = 10.4 and 12.0 MeV, proceeds via ⁹Be*(2.4) and to some extent via ⁹Be*(3.1, 4.7) and possibly some higher excited states. The dominant decay of ⁹Be*(2.4) is to ⁵He(0) + α while ⁹Be*(3.1, 4.7) decay to ⁸Be(0) + n (1971RE19). It should be noted, however, that the peaks corresponding to ⁹Be*(3.1) have a FWHM of ≈ 1 MeV, which may imply that ⁹Be*(2.8) is involved (1971RE19). See also (1978GR07) and ¹³C in (1981AJ01).

44. ¹¹B(¹⁶O, ¹⁸F)⁹Be Q_m = -8.290

See (1968OK06).

45. (a) ¹²C(n, α)⁹Be Q_m = -5.7015
(b) ¹²C(n, nα)⁴He⁴He Q_m = -7.2748

Angular distributions of the α₀ group have been measured at E_n = 13.9 to 18.8 MeV; ⁹Be*(1.7, 2.4, 3.1) are also populated: see (1974AJ01). Reaction (b) at E_n = 13 to 18 MeV involves ⁹Be*(2.4) (1966MO05). See also (1975AN01, 1976AN16), (1973PE19; theor.) and ¹²C in (1980AJ01), and ¹³C in (1981AJ01).

46. ¹²C(α, ⁷Be)⁹Be Q_m = -24.693

Angular distributions have been obtained for the transition to ⁷Be*(0, 0.43) + ⁹Be_g.s. (1972RU03: 42 MeV).

47. ¹²C(¹⁰B, ¹³N)⁹Be Q_m = -4.642

See (1975RA13; theor.).

48. ¹²C(¹⁸O, ²¹Ne)⁹Be Q_m = -6.398

See (1974BA15).

49. ¹³C(γ, α)⁹Be Q_m = -10.6479

See ¹³C in (1981AJ01).

50. ¹³C(p, pα)⁹Be Q_m = -10.6479

See (1975OB01) and ¹⁴N in (1981AJ01).

51. ¹³C(d, ⁶Li)⁹Be Q_m = -9.174

See (1966DE09).

52. ¹³C(³He, ⁷Be)⁹Be Q_m = -9.062

Angular distributions have been obtained at E(³He) = 70 MeV for the transitions to ⁹Be*(0, 2.4) and ⁷Be*(0, 0.43). Broad states at 2.9, 4.8 ± 0.2, 7.3 ± 0.2 and 11.9 ± 0.4 MeV are also populated (1976ST11).

53. ¹³C(α, ⁸Be)⁹Be Q_m = -10.740

At E_α = 65 MeV angular distributions have been measured for the transitions to ⁹Be*(0, 2.4) (1976WO11).

54. (a) ¹³C(¹⁷O, ²¹Ne)⁹Be Q_m = -3.300
(b) ¹³C(¹⁸O, ²²Ne)⁹Be Q_m = -0.980

See (1974CH1Q) and (1978EN06).

55. ¹⁴C(¹⁸O, ²³Ne)⁹Be Q_m = -3.956

See (1974BA15) and (1978EN06).

56. ¹⁶O(α, ¹¹C)⁹Be Q_m = -24.310

See (1972RU03).