A=9Be (1974AJ01)

1. (a) ⁶Li(t, n)⁸Be Q_m = 16.024 E_b = 17.6895
(b) ⁶Li(t, p)⁸Li Q_m = 0.801
(c) ⁶Li(t, d)⁷Li Q_m = 0.9930
(d) ⁶Li(t, α)⁵He Q_m = 15.22
(e) ⁶Li(t, n)⁴He⁴He Q_m = 16.116

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). 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 reactions (c) and (d) see (1966LA04). For reaction (e) see (1966LA02, 1967BE13). See also ⁵He, ⁷Li and ⁸Li.

2. ⁶Li(α, p)⁹Be Q_m = -2.1251
Q₀ = -2.1256 ± 0.0012 (1967BR1B).

Angular distributions of ground state protons have bee measured at E_α = 10.2, 11.5 and 13.5 MeV (1960MA15), 13.6 and 14.7 MeV (1962KO13) and 30 MeV (1960KL03). See also (1966LA04).

3. ⁶Li(⁶Li, ³He)⁹Be Q_m = 1.895

See (1964KI02).

4. ⁷Li(d, γ)⁹Be Q_m = 16.6965

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*(16.977) with Γ_cm < 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 100/8.5 ± 4.3/10.6 ± 5.3/ - / ≤ 4.5/9.6 ± 4.8 (1965IM01), 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). See also (1968SN1A).

5. (a) ⁷Li(d, n)⁸Be Q_m = 15.031 E_b = 16.6965
(b) ⁷Li(d, α)⁵He Q_m = 14.23
(c) ⁷Li(d, n)⁴He⁴He Q_m = 15.1233

The yield of neutrons has been measured for E_d = 0.2 to 4.8 MeV (1952BA64, 1957SL01, 1965IM01), 0.86 to 1.33 MeV by (1969NU1C), 3 to 8 MeV by (1967KE1F: yield of neutrons to ⁸Be*(16.6, 17.6, 18.1), at one MeV intervals) and 5 to 19 MeV by (1973WE19). Polarization measurements have been reported by (1971MO1R, 1973MO07: E_d = 0.64 MeV; n₀) and (1970TH08: E_d = 2.5 to 3.7; n₀, n₁). See also (1972SE09; theor.) and (1966LA04). Resonances in the yield of neutrons are observed at E_d = 0.36, 0.68, 0.98 and (1.8) MeV: see Table 9.3 (in PDF or PS).

The yield of α-particles has been measured for E_d = 0.2 to 0.3 MeV by (1964MA60), 0.6 to 2.0 MeV by (1971FR04), 0.7 to 1.6 MeV (1969DE31) and 0.7 to 3.0 MeV by (1963PA04). The excitation function for reaction (b) shows resonances at E_d = 0.75 and 1.00 MeV (1971FR04), 0.78 and 1.08 MeV (1969DE31), as well as a broad structure at E_d = 2.5 MeV (1963PA04). Also reported are α-particles from reaction (a) associated with ⁸Be*(11.4, 16.6, 16.9); the α-particles from the decay of ⁸Be*(11.4) seems to show resonance behavior at E_d = 0.7, 1.0 and 1.75 MeV. It is not clear whether the α-particles corresponding to ⁸Be*(16.6) show resonance at E_d = 2.5 MeV or whether the ⁸Be*(16.9) α-particles are appearing at this point (1963PA04).

A study of the B_L coefficients of the angular distributions of the α₀ group for E_d = 0.45 to 2.0 MeV and of the α-α angular correlation coefficient, together with a re-analysis of the (d, d₀) data of (1964FO13), lead to assignments of 3/2^- and (3/2, 5/2)⁺ for ⁹Be*(17.30, 17.50). The analysis also requires a (3/2, 5/2)^- state at lower excitation energy and a (3/2, 5/2)⁺ state at higher energy (1972DE44). See also (1973MO07) for an interpretation of results from reaction (a).

A kinematically complete study of reaction (c) at E_d = 1.0 MeV shows that the yield is dominated by sequential decay via ⁸Be*(2.9) and ⁵He_g.s.. There is evidence also for the involvement of ⁹Be*(17.50) [measurement of relative yield for E_d = 0.9 to 1.1 MeV]: J = 3/2 is suggested (1973HE26). See also ⁵He, ⁸Be and (1966AS04, 1967KE1F, 1967VA11, 1968WI1E, 1973HE06). See also (1966NU1B, 1966PO1D, 1967BE13, 1967WI1C, 1968DA1H, 1971DA21, 1972BR1R, 1972SU1E, 1973DA1R).

6. ⁷Li(d, p)⁸Li Q_m = -0.1919 E_b = 16.6965

The yield of p₀ measured for E_d = 0.29 to 0.78 MeV shows a single resonance with E_d = 360 ± 3 keV, Γ < 2 keV, Γ_p/Γ_γ ≈ 0.5 (1965IM01, 1965WO01): see also reaction 4.

The yield of ⁸Li has been measured for E_d = 0.4 to 4 MeV (1952BA64, 1954BA46, 1956BE1A, 1960KA05), for E_d = 0.62 to 1.97 MeV by (1972SC1U) and for E_d = 2.0 to 7.0 MeV by (1973AB10): observed resonances are displayed in Table 9.3 (in PDF or PS). The yield of 0.98-MeV γ-rays [from ⁷Li(d, p)⁸Li*] rises monotonically from E_d = 1.9 to 3.3 MeV (1962CH14).

The total cross section at the E_d = 0.77 MeV resonance is 202 ± 9 mb (1972SC1U). Earlier values were 176 ± 15 mb (1960KA05) and 211 ± 15 mb (1966PA16). We adopt 205 ± 8 mb. This cross section is important since the ⁷Be(p, γ)⁸B data are normalized to it and the S-factor is of interest in relation to the solar neutrino problem: see (1968PA1M). See also ⁸Li.

7. ⁷Li(d, d)⁷Li E_b = 16.6965

The upper limit for the relative partial width for elastic scattering at E_d = 0.36 MeV (⁹Be* = 16.98), Γ_d₀/Γ_γ is 400 (1965IM01).

The elastic scattering, at 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)] (1964FO13) [and discussion in (1972DE44) and in reaction 5]. The elastic scattering cross section (θ_cm = 162°) decreases monotonically for E_d = 10.0 to 12.0 MeV (1971BI11). See also ⁷Li.

8. (a) ⁷Li(d, t)⁶Li Q_m = -0.993 E_b = 16.6965
(b) ⁷Li(d, ³He)⁶He Q_m = -4.488

The cross section for reaction (a) rises 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.

9. ⁷Li(t, n)⁹Be Q_m = 10.4389

See (1959AJ77, 1962SE1A) and ¹⁰Be.

10. (a) ⁷Li(³He, p)⁹Be Q_m = 11.2027
(b) ⁷Li(³He, np)⁸Be Q_m = 9.538

Observed proton groups are listed in Table 9.4 (in PDF or PS) (1968CO07). See also Table 9.5 (in PDF or PS) in (1966LA04) for a listing of the older work. Angular distributions have been measured for the protons to ⁹Be*(0, 1.7, 2.4, 3.1) at E(³He) = 0.90 to 1.10 MeV (1971ST35: not to ⁹Be*(1.7)), 2.2 to 3.2 MeV (1969SA04, 1972LI31) and at E(³He) = 10 MeV (1970DI12, 1970DI1F), and for the group corresponding to ⁹Be*(14.39) at E(³He) = 10 MeV (1971AD01). The characteristics of the neutron and γ-decays of ⁹Be states are displayed in Tables 9.5 (in PDF or PS) and 9.6 (in PDF or PS) (1965GR08, 1965LY01, 1966CH20, 1968CO08, 1968KR02, 1971AD01, 1972AD04, 1972MC1E). See also (1964MA57, 1970LI1Q), (1969BA1Z), (1968SA1G, 1968TA1N, 1970LK1A, 1971WE1L; theor.), ⁸Be and ¹⁰B.

11. ⁷Li(α, d)⁹Be Q_m = -7.1511

At E_α = 30 MeV angular distributions have been measured for the deuterons corresponding to ⁹Be*(0, 1.7, 2.4) (1972ME07). See also (1971BU1K; theor.) and (1966LA04).

12. ⁷Li(⁶Li, α)⁹Be Q_m = 15.223

At E(⁷Li) = 2.9 MeV α-particle groups are observed corresponding to ⁹Be*(0, 1.7, 2.4, 3.1, 11.9 ± 0.2 [Γ = 0.5 ± 0.1 MeV]) (1964ME07). Angular distributions of the α₀ group have been measured at E(⁷Li) = 3.78 to 5.95 MeV (1967KI03). At E(⁶Li) = 26.0 MeV and E(⁷Li) = 30.3 MeV the excitation of ⁹Be*(0, 11.8, 13.8, 15.2, 17.8, 21.0) is reported (1971GL07). See also (1967CH34, 1968DA20, 1970OG1A) and (1966RO1E, 1966RO1F, 1966RO1H, 1969RO1G; theor.).

13. ⁷Li(¹¹B, ⁸Be)⁹Be Q_m = 7.286

See (1970LK1A; theor.).

14. ⁹Li(β^-)⁹Be Q_m = 13.618

⁹Li decays by β^- emission with τ_1/2 = 176 ± 2 msec to ⁹Be*(0, 2.43, 2.78): see 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 allowed 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, 1970CH1T). See also (1963AL18, 1965SC17, 1973RO2F) and (1969MA11) for a general discussion of the problems in identifying the parameters of the low-lying states of ⁹Be.

15. (a) ⁹Be(γ, n)⁸Be Q_m = -1.6651
(b) ⁹Be(γ, α)⁵He Q_m = -2.46
(c) ⁹Be(γ, n)⁴He⁴He Q_m = -1.5732
(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). 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). A satisfactory fit to the cross section is obtained with a one-level approximation of R-matrix theory (1968BA1C). Peaks in the cross section of (γ, xn) are reported corresponding to E_x = 2.43 ± 0.03, 3.00 ± 0.03, 19.00 ± 0.03, 21.50 ± 0.05 and 23.9 ± 0.1 MeV, and there is some indication also of structure at E_x = 9.1, 10.8, 12.8 and 14.8 MeV (1973HU1G). See also (1966CO16, 1972TH12) and (1966LA04) for references to earlier work.

The total absorption cross section has been measured for E_γ = 10 to 155 MeV by (1972AH1B, 1973AH1A)^†. The integrated cross section for E_γ = 16 to 29 MeV is 53 MeV · mb (1972AH1B). (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). See also (1965WY02).

^† We are deeply indebted to E.G. Fuller for his very helpful remarks on the ⁹Be + γ processes.

See (1966LA04) for a discussion of the early evidence on ⁹Be levels from reaction (a). See also (1966TH03, 1967GL1B, 1968AD09, 1968KA38, 1971KA70, 1972BU1R, 1972CR1E), (1967SH1E) and (1965BO1B, 1965MA1H, 1967BO1K, 1967BO34, 1969BO1U, 1968MA1Y, 1968MA1X, 1968PA1H, 1969AU05, 1970SA17, 1972TA31, 1973SL02; theor.).

16. (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 resonances 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 (1966LA04) and (1966VO06, 1968AD09). See also (1965KO1B, 1969AN1H, 1971AN04, 1973DO13), (1967SH1E, 1973CO1N) and )1968MA1X; theor.).

17. (a) ⁹Be(γ, d)⁷Li Q_m = -16.6965
(b) ⁹Be(γ, t)⁶Li Q_m = -17.6895

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 (1966LA04) and (1966VO06, 1968AD09, 1969AN1H, 1971AN04, 1971AN15) for reaction (a) and (1966VO06, 1972AN09) for reaction (b). See also (1968MA1X; theor.).

18. ⁹Be(γ, γ)⁹Be

See (1967LO1B, 1968SN1A, 1969MO1H).

19. (a) ⁹Be(e, e)⁹Be
(b) ⁹Be(e, en)⁸Be Q_m = -1.6651
(c) ⁹Be(e, ep)⁸Li Q_m = -16.888
(d) ⁹Be(e, eα)⁵He Q_m = -2.46

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

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

< r² >^1/2 = 2.43 ± 0.08 fm, Q = 3 fm² (1969BE21).

See also (1966AF1A, 1967BE26, 1967BE1P, 1973SL02). (1973LA1T) report b = 1.80 ± 0.03 fm from magnetic scattering.

The elastic scattering of electrons has been studied at E_e up to 700 MeV: see (1966LA04), the references listed above, and (1965VA1G, 1966RA29, 1969BE50). Magnetic elastic scattering at θ = 180° gives indication of both M1 and M3 contributions [(1965GR18, 1966RA29): see (1968KU1D)].

Inelastic scattering reveals a number of levels: Table 9.8 (in PDF or PS) displays the parameters of these states (1960BA47, 1962ED02, 1963NG01, 1965NG1A, 1966CL01, 1967AR1A, 1968CL08, 1968VA05, 1973BE19, 1973SL02). See also (1966LA04) for a discussion of the earlier work.

Electron bremsstrahlung has been measured at E_e = 1.0 and 2.0 MeV by (1968RE11). See also (1966PE1E), (1968GO1J) and (1965GR1E, 1965NE1B, 1966DE1K, 1966KU1C, 1967KA1A, 1967ST1G, 1967WA1E, 1967WA1F, 1968JA1D, 1968KU1B, 1969BO1V, 1969BO19, 1969VI02, 1970BE1G, 1970TI1C, 1971DRZW, 1971GO14, 1972BL12, 1972BO01, 1973OK1B; theor.).

For reaction (b) see (1970AL1M; theor.). For reaction (c) see (1968AM1A, 1968BO46, 1970HI1F, 1970RE1E) and (1965AL1F, 1973HI03; theor.). For reaction (d) see (1973JU1E).

20. (a) ⁹Be(n, n)⁹Be
(b) ⁹Be(n, 2n)⁸Be Q_m = -1.6651

The neutron spectrum at E_n = 3.7 MeV is consistent with the excitation of ⁹Be*(0, 1.7, 2.4, 3.1) with subsequent neutron decay of the two higher states (1957HU14, 1958WA05). About 1/2 of the inelastic processes involve ⁹Be*(2.4) for E_n = 2.6 to 6.0 MeV; that level decays only (12 ± 5)% via ⁸Be(0) + n (1959MA34). See Table 9.5 (in PDF or PS). At E_n = 14 MeV ⁹Be*(6.8) appears to be excited (1963JE05). Angular distributions have been measured at E_n = 14 MeV (1958AN32, 1958NA09, 1968RO1H, 1969RO1F; n₀, n₂). See also ¹⁰Be, (1966LA04) and (1965BO19, 1965FR1B, 1965GO1E, 1966AM1A, 1966BO1C, 1966BO1F, 1967BO1F, 1970DR11) and (1969WA11; theor.).

21. ⁹Be(p, p)⁹Be

The elastic scattering has been studied at many energies for E_p = 5 to 725 MeV: see (1966LA04). More recent angular distribution measurements have been carried out at E_p = 2.009 to 2.099 MeV (1970SI12; p₀), 6.36 and 6.48 MeV (1971VA34; p₁), 13.0, 14.0, 15.0, 21.35 and 30.3 MeV (1973VO02; p₀, p₂), 17.0, 21.0, 25.0, 29.1 (1973MO01; p₀, p₂ and p to ⁹Be*(3.1)), 33.6 MeV (1970KU1D; p₀), 46 MeV (1967SA13, 1967VE01; p₀, p₂ and p to ⁹Be*(11.3, 14.4, 16.7, 17.5)), 49.75 MeV (1971MA13, 1971MA44; p₀, p₂ and p to ⁹Be*(6.4)), and 100 MeV (1966MA38, 1968LI1C; p₀, p₂ and p to ⁹Be*(4.7, 6.8)). The elastic angular distributions show pronounced diffraction maxima characteristic of the optical model. See (1973MO01) for a discussion of optical model parameters. (1973VO02), in coupled channels analysis, find that a quadrupole-deformed optical model potential with a deformation parameter β = 1.1 [see also (1967SA13)] provides an improved description of the elastic data and a good fit to the p₂ data [to ⁹Be*(2.4)].

The structure corresponding to ⁹Be*(1.7) is asymmetric: the line shape peaks 25⁺¹⁵_-11 keV above the threshold for ⁸Be + n (1970TU06): see also the discussions in (1960SP08, 1971JE03) and in (1966LA04). The energy of ⁹Be*(2.4) is given as 2433 ± 5 (1951BR72), 2434 ± 5 (1956BO18), 2432 ± 4 (1955GO48), 2430 ± 5 keV (1960SP08). ⁹Be*(3.1) has a width of 250 ± 5 keV (1960SP08): E_x = 3.03 ± 0.03 MeV (1956BO18), 3.04 ± 0.05 MeV (1960SP08), J^π = 3/2⁺, 5/2⁺. 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] (1956BE14, 1965HA17). See also Table 9.8 (in PDF or PS) in (1966LA04). (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) in this reaction is consitent 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 discussion in (1966LA04). See also (1966MA38).

22. (a) ⁹Be(p, 2p)⁸Li Q_m = -16.888
(b) ⁹Be(p, pd)⁷Li Q_m = -16.6965
(c) ⁹Be(p, pα)⁵He Q_m = -2.46
(d) ⁹Be(p, pn)⁸Be Q_m = -1.6651
(e) ⁹Be(p, p³He)⁶He Q_m = -21.181

The summed proton spectrum (reaction (a)) shows two peaks with Q = -16.4 ± 0.3 and Q = -25.4 ± 0.5 MeV, corresponding to removal of a p-proton and an s-proton respectively, and a third peak of uncertain assignment with Q = -32.3 ± 0.6 MeV (probably due to unresolved states) (1966TY01: E_p = 460 MeV). See also (1966LA04), (1966WA12, 1968PE1A), (1965BE1E, 1966JA09, 1966JA1A, 1967BE1Q, 1967JA1E, KO67Q, 1968JA1G, 1969KO1J; theor.) and ⁸Li. For reaction (b) see (1966LA04) and (1973KO1M). Reaction (c) is characterized by a sequential mechanism at low energies and by a quasi elastic scattering mechanism at higher energies. At E_p = 26.0, 35.0, 46.8 and 57 MeV the data are consistent with quasi free scattering of the incident protons by zero-momentum α-particle clusters in ⁹Be: the probability of finding such clusters at these four energies is determined to be 0.166, 0.099, 0.124 and 0.09, respectively (1968RO19, 1970QU1C, 1972QU01). See also (1967TA1C, 1969YA1B, 1970GO12, 1973WO1E), (1969HO1K, 1971GA1J) and (1973HO30; theor.).

For reaction (d), see (1969WI1F, 1970TH1F, 1971HU1A, 1973MI1J) and (1967BE1Q; theor.). For reaction (e) see (1969KO1G). See also (1968KO1E, 1969ED01).

23. ⁹Be(d, d)⁹Be

Elastic scattering has been studied at many energies in the range E_d = 7.8 to 27.7 MeV: see (1966LA04). Elastic angular distributions are also reported for E_d = 1.1 to 2.5 MeV (1968MA1H), 4.5 to 6.0 MeV (1970PO03), 5.00 to 7.00 MeV (1971DJ02), 11.8 MeV (1967FI07; also d₂), 12.8 MeV (1973VA08; d₁), 13.6 MeV (1968VE11, 1968VE1C, 1970VE06, 1972MA47), 14.35 MeV (1966NG01; also d₂), 15.0 MeV (1969AR1B), 15.8 MeV (1966CO24; also d₂) and 410 MeV (1960BU25; forward angles). For optical model parameters see discussions in (1966CO24, 1967FI07).

Inelastic deuteron groups have been observed 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 (1963ST1A, 1969VE09, 1970EL16, 1973ZW1A; theor.) and ¹¹B.

24. (a) ⁹Be(t, t)⁹Be
(b) ⁹Be(t, nt)⁸Be Q_m = -1.6651

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).

25. ⁹Be(³He, ³He)⁹Be

Angular distributions of elastically scattered ³He particles have been obtained at E(³He) = 4, 6, 8, 10, 15 and 18 MeV (1969PA11), 6.0 and 8.0 MeV (1967EA01), 13.2, 20.4, 22.2 and 27.0 MeV (1972BU30), 22.7 and 32.3 MeV (1965AR1E), and 217 MeV (1973WI07). See also (1970BA1P). For optical model parameters see discussions in (1972BU30, 1973WI07). 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) (1968BA1E, 1969BA06). See also (1968HO1C, 1968PA1P, 1969HO27; theor.), (1966LA04) and reaction 28 in ⁶Li.

26. (a) ⁹Be(α, α)⁹Be
(b) ⁹Be(α, 2α)⁵He Q_m = -2.46
(c) ⁹Be(α, αn)⁸Be Q_m = -1.6651

Elastic scattering has been studied at many energies for E_α = 9.5 to 48 MeV: see (1966LA04). Recent measurements of the angular distributions of α₀ are reported at E_α = 8.76, 9.27 and 10.13 MeV (1967BR39), 28.5 MeV (1967FU08; also α₂, and partial angular distributions for α₁ and α₃) and 104 MeV (1969HA14, 1970HA1G, 1972DE01, 1972DE02). 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 the 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 group corresponding 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: E_α = 48 MeV) and (1967FU08: E_α = 28.5 MeV). Analysis based on the rotational model leads to a deformation coefficient β₂ = 0.46 (1959BL31), 0.34 ± 0.01 (1964GR39). See also (1966GR1E, 1966GR1F, 1968LI1E, 1970WO1B, 1972DM01, 1972RA34).

The summed α-spectra from reaction (b) show a peak corresponding to quasi-elastic scattering leaving ⁵He in the ground state. The angular distribution peaks at the angle corresponding to a zero-momentum α-cluster. The probability of formation of such clusters is 7⁺¹³_-5% (1969PI11, 1970PI1D: E_α = 55 MeV). See also (1965YA02, 1968YA02, 1969DO02, 1969DO03) and ⁵He. The reaction cross section has been measured at E_α = 42.8 and 49.2 MeV by (1971GU15).

See also (1965HI1B, 1965KU1B, 1966HI1A, 1967ME1C, 1968BA1H, 1968TA1K, 1969BA1J, 1970MI12, 1972AV04, 1972HI16; theor.) and (1971GA1J).

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, 3.0) (1972OB01). See also (1971GE09, 1973GE1J, 1973WE03).

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

Elastic angular distributions have been measured at E(⁶Li) = 24 MeV (1968DA20) and E(⁷Li) = 24 MeV (1972WE08). See also (1970LK1A; theor.) for reaction (b).

28. ⁹Be(¹²C, ¹²C)⁹Be

Elastic scattering angular distributions have been obtained at E(¹²C) = 12, 15, 18 and 21 MeV. The neutron spectroscopic factor for ⁹Be is 0.84 (1970BA49).

29. ⁹Be(¹⁴N, ¹⁴N)⁹Be

Elastic angular distributions have been measured at E(¹⁴N) = 25 MeV (1966OE1A) and 27.3 MeV (1959HA28). See also (1966LA04), (1969BR1D) and (1965BO37).

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) and 30 MeV (1969KR03), and at E(¹⁸O) = 12.1, 16 and 20 MeV (1971KN05).

31. ¹⁰Be(d, t)⁹Be Q_m = -0.5544

Forward angular distributions have been obtained at E_d = 15.0 MeV for the tritions 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).

32. ¹⁰B(γ, p)⁹Be Q_m = -6.5853

See ¹⁰B.

33. ¹⁰B(e, ep)⁹Be Q_m = -6.5853

See (1969BA1F; theor.) and ¹⁰B.

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 (1966GO1D), (1966WE1B, 1971MI12), (1966LA04) and ¹¹B in (1975AJ02).

35. ¹⁰B(p, 2p)⁹Be Q_m = -6.5853

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 (1965BE1E, 1966JA09, 1966JA1A, 1967JA1E, 1967KO1B, 1968JA1G; theor.), ¹⁰B and (1966LA04).

36. ¹⁰B(d, ³He)⁹Be Q_m = -1.0916

Angular distributions of the ³He groups corresponding to ⁹Be*(0, 2.4) have been measured at E_d = 11.8 MeV (1966BA21, 1967FI07: S_exp = 0.76 and 0.66, respectively) and at 28 MeV [(1971IN1C); (1968GA13: ground state only)]. The data are very similar, as predicted, to those obtained in the mirror reaction: see reaction 12 in ⁹B. See also (1965SY02, 1971WA1K, 1972WA1M).

37. ¹⁰B(t, α)⁹Be Q_m = 13.229

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).

38. ¹⁰B(¹⁴N, ¹⁵O)⁹Be Q_m = 0.707

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

39. ¹⁰B(¹⁶O, ¹⁷F)⁹Be Q_m = -5.985

See (1968OK06).

40. ¹¹B(n, t)⁹Be Q_m = -9.5591

The angular distribution of the ground state group has been measured at E_n = 14.4 MeV (1970MI14).

41. (a) ¹¹B(p, ³He)⁹Be Q_m = -10.3229
(b) ¹¹B(p, pd)⁹Be Q_m = -15.8167

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). For reaction (b) see (1964BA1C).

42. (a) ¹¹B(d, α)⁹Be Q_m = 8.0309
(b) ¹¹B(d, nα)⁴He⁴He Q_m = 6.4577
Q₀ = 8.0297 ± 0.0028 (1967OD01). See also (1964MA57, 1967SP09).

Alpha groups are reported corresponding to ⁹Be*(0, 1.7, 2.4, 3.1). The width of ⁹Be*(1.7): Γ_cm = 224 ± 25 keV (1958KA31, 1966PU02). The energy of ⁹Be*(2.4) is 2422 ± 5 keV (1951VA08), 2431 ± 6 keV (1954EL10), 2424 ± 5 keV (1956BO18). The 5/2⁺ state is at E_x = 3.02 ± 0.03 MeV (1955LE36), 3.05 ± 0.03 MeV (1956BO18): Γ_cm = 257 ± 25 keV (1958KA31, 1966PU02).

Angular distributions are reported at E_d = 0.39 to 0.7 MeV (1965SA15; α₀, α₂), 0.8 to 2.5 MeV (1968CO31; α₀, α₂) and at 12.6 MeV (1966DR04; α₀, α₂). See also (1966ME1E; theor.).

The ratio of the γ-decay width to the total width, Γ_γ/Γ, of ⁹Be*(2.4) is (1.16 ± 0.14) × 10^-4. Since Γ_γ is known from (e, e') [see Table 9.8 (in PDF or PS)], Γ = 1.03 ± 0.18 keV. For ⁹Be*(1.7), Γ_γ/Γ ≤ 2.4 × 10^-5 (1966PU02).

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 ⁹Be(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 ⁸Be, ¹³C in (1976AJ04) and (1966LA04).

43. ¹¹B(¹⁶O, ¹⁸F)⁹Be Q_m = -8.290

See (1968OK06).

44. (a) ¹²C(n, α)⁹Be Q_m = -5.7016
(b) ¹²C(n, nα)⁴He⁴He Q_m = -7.2748

Angular distributions of the α₀ group have been measured at E_n = 14.1 MeV (1969HS02, 1969KI02), 13.9 and 15.6 MeV (1968BR21), and 14.8 to 18.8 MeV (1971SA31). (1968BR21, 1969HS02) also report the population of ⁹Be*(1.7, 2.4, 3.1). Reaction (b) at E_n = 13 to 18 MeV involves ⁹Be*(2.4) (1966MO05). See also (1965MO09, 1966MI1D, 1968BE1J, 1969KA1D, 1969LO1D, 1971DO1K, 1971FA04), (1966CI1A, 1966LA04), (1967EL1D, 1968CH1J; theor.), ¹²C in (1975AJ02), and ¹³C in (1976AJ04).

45. ¹²C(α, ⁷Be)⁹Be Q_m = -24.694

Angular distributions have been obtained for the transitions to ⁷Be*(0, 0.43) + ⁹Be(0) (1972RU03; 42 MeV). See also (1971LE33).

46. ¹³C(γ, α)⁹Be Q_m = -10.6480

See ¹³C in (1976AJ04).

47. ¹³C(p, pα)⁹Be Q_m = -10.6480

See (1971BR07).

48. ¹³C(d, ⁶Li)⁹Be Q_m = -9.174

A partial angular distribution involving the transition to ⁶Li(0) + ⁹Be(0) has been measured at E_d = 14.6 MeV (1966DE09).

49. ¹⁶O(α, ¹¹C)⁹Be Q_m = -15.387

The angular distribution involving the transition to ¹¹C(0) + ⁹Be(0) has been measured at E_α = 42 MeV (1972RU03).