A=8Be (1974AJ01)

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⁸Be (1974AJ01)

(See Energy Level Diagrams for ⁸Be)

GENERAL: See also (1966LA04) and Table 8.3 [Table of Energy Levels] (in PDF or PS).

Shell model: (1965CO25, 1965VO1A, 1966BA26, 1966GU06, 1966HA18, 1966PA15, 1967BA1K, 1967BO1C, 1967HS1A, 1967PA10, 1967ST1C, 1967SV1A, 1968BA1L, 1968FA1B, 1968GO01, 1969AB1D, 1969GU1E, 1969GU03, 1969IK1A, 1969KU1F, 1969SV1A, 1970BA75, 1970BO1J, 1970CO1H, 1970DE1F, 1970GU11, 1970KO04, 1970KR1D, 1970NO1C, 1970RU1A, 1970TU01, 1970WO12, 1970ZO1A, 1971BO22, 1971BO29, 1971CO28, 1971GU20, 1971HA1U, 1971NO02, 1972AB12, 1972BO38, 1972HA05, 1972LE1L, 1973BO07, 1973HA05, 1973HA49, 1973JO1K).

Collective and deformed models: (1962MO1B, 1965VO1A, 1967LA09, 1967PA10, 1969AB05, 1969RU04, 1970BO41, 1970GO1Q, 1971BO22, 1971BO29, 1971HO19, 1972AB1C, 1972BO38, 1972HA05, 1972HO56, 1973BO07, 1973HO40, 1973KO1F, 1973KU13, 1973PE08).

Cluster and α-particle model: (1965IN1A, 1965NE1B, 1966KA1A, 1966PA15, 1966WE1C, 1969AB1B, 1969AB1D, 1969IK1A, 1969KU1C, 1969KU1F, 1969ME1C, 1969TA1C, 1970BA75, 1970YU1B, 1971AB07, 1971AB1B, 1971FR06, 1971KH06, 1971LE1N, 1971NO02, 1972AB1C, 1972AB19, 1972AK10, 1972BA59, 1972FR1B, 1972GR42, 1972HA05, 1972HI16, 1972HO56, 1972IK1A, 1972LE1L, 1972VA45, 1973HO40).

Special levels: (1966BA26, 1966BR1H, 1966DA02, 1966GU06, 1966PA15, 1966ST1D, 1967BA1N, 1967HO03, 1967HS1A, 1967MA1B, 1967ST1C, 1968GO01, 1968LA1B, 1969BA43, 1969GU03, 1969HA1G, 1969HA1F, 1969SH1A, 1970BO1J, 1970KI1D, 1970PE18, 1970RU1A, 1971AN03, 1971CO28, 1971GU20, 1971NO02, 1972BE1E, 1972HA1R, 1972VA45, 1973AS02, 1973BO07, 1973FE1J, 1973HO40, 1973MA1K, 1973ST1Q).

Electromagnetic transitions: (1965CO25, 1966BA26, 1966PA15, 1966WA1E, 1967HS1A, 1968LA1B, 1969AB05, 1969HA1G, 1969HA1F, 1971BO22, 1972AB12, 1972BO38, 1972HA05, 1972NA05, 1973AS02, 1973BO07, 1973HA49, 1973HA1Q).

Special reactions: (1966ME1D, 1967GO1F, 1968BA61, 1968CH1F, 1969DE1M, 1969VI1C, 1970RA1J, 1972BI10, 1972CR1F, 1972HA2F, 1973JO07, 1973KO1P).

Other topics: (1965CO25, 1965VO1A, 1966DA02, 1966GU06, 1966HA18, 1966PA15, 1966TO04, 1966YO1B, 1967BA1K, 1967BA12, 1967BA1M, 1967BO1G, 1967BO1C, 1967BR1E, 1967CA17, 1967DI1B, 1967LA09, 1967LA1G, 1967PA10, 1967SV1A, 1968BA1L, 1968FA1B, 1968GO01, 1968LA1B, 1968NE1C, 1969AB05, 1969GU03, 1969KU1F, 1969HO1M, 1969KE1B, 1969NA1E, 1969NA1L, 1969RU04, 1969SH1A, 1969SV1A, 1970BA75, 1970BO1J, 1970CO1H, 1970GR44, 1970HO1J, 1970KO04, 1970KR1D, 1970NO1C, 1970PE18, 1970RU1A, 1970TU01, 1970ZO1A, 1971AN03, 1971DE1V, 1971GR2C, 1971HO19, 1971JE1B, 1971SO11, 1971ST40, 1971ZA1D, 1972AB12, 1972AN05, 1972EL1C, 1972FR1B, 1972HA05, 1972HA57, 1972LE1L, 1972LE23, 1972PN1A, 1972VA45, 1973HA05, 1973JO1K, 1973JU2A, 1973KO26, 1973NA26, 1973RA1E, 1973RO1R, 1973ST1Q).

Ground state: (1965CO25, 1965VO1A, 1966BA26, 1966TO1B, 1967BO1G, 1967BR1E, 1967LA1G, 1967PA10, 1968BA1L, 1968BO19, 1968FA1B, 1969AB05, 1969GU03, 1969KE1B, 1969KU1F, 1970GR44, 1970KO04, 1970KR1D, 1970TU01, 1971BO29, 1971GR2C, 1971RU14, 1972AB12, 1972GR42, 1972LE1L, 1972VA45, 1973KO26, 1973MA1K).

Adjusted mass excess^† of ⁸Be: 4941.87 ± 0.13 keV (1972WA1G).

^† Not used in Q_m calculations in this paper.

1. ⁸Be → ⁴He⁴He Q_m = 0.09189
Q₀ = 92.6 ± 0.8 keV (1966RE02).

In α - α scattering (reaction 4) the Q₀ is found to be 92.12 ± 0.05 keV, Γ_c.m. = 6.8 ± 1.7 eV (1968BE02). See also (1966LA04) for earlier values.

2. ⁴He(α, γ)⁸Be Q_m = -0.09189

Radiative widths have been measured for ⁸Be*(16.6, 16.9): see (1974NA1H: E_α = 31 to 35 MeV).

3. (a) ⁴He(α, n)⁷Be Q_m = -18.9921 E_b = -0.09189
(b) ⁴He(α, p)⁷Li Q_m = -17.348

For reaction (a) see (1952WA31). For reaction (b) see ⁷Li.

4. ⁴He(α, α)⁴He E_b = -0.09189

Alpha - α scattering reveals the ground state as a resonance with Q₀ = 92.12 ± 0.05 keV, Γ_c.m. = 6.8 ± 1.7 eV, [τ = (0.97 ± 0.24) × 10^-16 sec] (1966BE05, 1968BE02). Effective range theory analysis of higher energy scattering yields widths consistent with this value but subject to considerable uncertainty (1966TO1B). However, (1967KE1B, 1967KE1E) and (1967RA1B) have carried out such analyses yielding Γ = 6.14 ± 0.04 eV and 6.4⁺0.8_-0.5 eV, respectively. Using a three-level, one-channel R-matrix formalism (1968BA2D) find Γ = 5.1 ± 0.4 eV for the ground state of ⁸Be. R-matrix analysis of the s-wave scattering and of the ⁹Be(p, d)⁸Be reaction indicates the presence of a second 0⁺ state at E_x ≈ 6 ± 3 MeV, Γ = 9 ± 4 MeV (a₀ = 7 fm) (1968BA2D). For E_α = 30 to 70 MeV the l = 0 phase shift shows resonant behavior at E_α = 40.7 MeV, corresponding to a 0⁺ state at E_x = 20.2 MeV, Γ < 1 MeV, Γ_α/Γ < 0.5. No evidence for other 0⁺ states is seen above E_α = 43 MeV (1972BA83).

The d-wave phase shift becomes appreciable for E_α > 2.5 MeV and passes through resonance at E_α = 6 MeV (E_x = 3.18 MeV, Γ = 1.5 MeV, J^π = 2⁺) (1963TO02). See Table 8.4 (in PDF or PS). Analyses by many-level R-matrix theory of the α-scattering, of the ⁹Be(p, d)⁸Be reaction and of the ⁸Li and ⁸B β-decays lead to approximately correct values for the E_x and Γ of ⁸Be*(2.9) and suggest a second 2⁺ state at E_x ≈ 8.5 MeV, Γ ≈ 10.5 MeV (1969BA43: a₂ = 6.75 fm), E_x = 12.0^-3.0_+3.5 MeV, Γ = 14^-3₊₄ MeV (1969CL10: a₂ = 6.0 ± 0.5 fm). Five 2⁺ levels are observed from the l = 2 phase shifts measured from E_α = 30 to 70 MeV: ⁸Be*(16.6, 16.9) with Γ_α = Γ, and states with E_x = 20.2, 22.2 and 25.2 MeV. The latter has a small Γ_α (1972BA83). See also reaction 11.

The l = 4 shift rises from E_α ≈ 11 MeV and indicates a broad 4⁺ level at E_x = 11.4 ± 0.3 MeV (1959BR71). See also (1973CH1W). A rapid rise of δ₄ at E_α = 40 MeV corresponds to a 4⁺ state at 19.9 MeV with Γ_α/Γ ≈ 0.96; Γ < 1 MeV and therefore Γ_α < 1 MeV, which is < 5% of the Wigner limit. A broad 4⁺ state is also observed near E_α = 51.3 MeV (E_x = 25.5 MeV) but there is no evidence for a previously reported state at E_x = 27.5 MeV (1972BA83).

Over the range E_α = 30 to 70 MeV a gradual increase in δ₆ is observed (1972BA83). Some indications of a 6⁺ state at E_x ≈ 28 MeV and of an 8⁺ state at ≈ 57 MeV have been reported by (1965DA11), with Γ_c.m. ≈ 20 and ≈ 73 MeV, respectively. The elastic scattering has been studied at E_α = 140 MeV by (1972FR1K). For a listing of the older work see Table 8.7 (in PDF or PS) [(dσ/dΩ)], Table 8.8 (in PDF or PS) [parameters of ⁸Be states from ⁴He(α, α)] and Table 8.9 (in PDF or PS) [parameters of ⁸Be*(2.9)] in (1966LA04). See also (1972FR1J). For studies of inelastic scattering of α-particles from ⁴He see (1969GR06, 1971HA41) and the review in (1973FI04). See also (1965SL1A, 1967ST30, 1968CO1M).

The bremsstrahlung cross section has been measured at E_α = 9.35 MeV and for E_α = 11.4 to 13.5 MeV: no significant enhancement is found at the final state energy corresponding to ⁸Be*(2.9) (1972FR02, 1973FR17). The cross section has also been measured for E_α = 12.1 to 18.7 MeV by (1972PE16).

5. ⁶Li(d, γ)⁸Be Q_m = 22.282

Not observed: (1953SA1A, 1954SI07).

6. (a) ⁶Li(d, n)⁷Be Q_m = 3.382 E_b = 22.282
(b) ⁶Li(d, n)⁴He + ³He Q_m = 1.795

The yield curve has been measured for E_d = 0.06 to 5.5 MeV [see (1966LA04) and (1966SC26)], and at E_d = 12 to 17 MeV (1970GA07: population of ⁷Be*(0 + 0.43)). A broad s-wave resonance is indicated at E_d = 0.41 MeV, Γ = 0.45 MeV (1952BA64, 1956NE13). Polarization measurements are reported at E_d = 0.27 to 0.60 MeV (1966MI06; n₁) and 2.5 to 3.7 MeV (1970TH08; n₀, n₁). The distributions observed by (1970TH08) are quite constant over the range 2.5 to 3.7 MeV, indicating that the predominant reaction mechanism is direct. See also ⁷Be.

Comparisons of the populations of ⁷Be*(0, 0.43) and of ⁷Li*(0, 0.48) have been made at many energies, up to E_d = 7.2 MeV. The n/p ratios are closely equal for analog states, consistent with charge symmetry (1957WI24, 1963BI27, 1963CR08). See also (1966AU1A).

7. (a) ⁶Li(d, p)⁷Li Q_m = 5.026 E_b = 22.282
(b) ⁶Li(d, p)⁴He + ³H Q_m = 2.559

Excitation functions have been measured for E_d = 30 keV to 5.4 MeV [see (1966LA04) and (1966LO18, 1968BE1P, 1969BL14)]. A broad maximum near E_d = 1.0 MeV is interpreted as indicating a level at E_d = 0.4 MeV (1950WH02). In the range E_d = 1 to 5 MeV there is evidence for both direct interaction and compound nucleus formation (1963BI27, 1963ME09, 1964PA06): at back angles the (d, p₁) data show evidence of the E_d = 3.7 MeV resonance [see ⁶Li(d, α)⁴He]. An anomaly is observed in the p₁/p₀ intensity ratio at E_d = 6.945 MeV, corresponding to the J^π = 0⁺; T = 2 analog of the ground state of ⁸He: E_x = 27.483 ± 0.010 MeV, Γ = 10 ± 3 keV, Γ_p₀ ≪ Γ_p₁, Γ_p₀ < Γ_d (1969BL14). The parameters of this state have been calculated by (1969BA36).

Polarization measurements have been made at E_d = 0.6 and 0.96 MeV (1969NA1J, 1972SE09; p₀, p₁) and at E_d = 2.1 to 10.9 MeV (1968DU09, 1968FI07, 1970FI07; p₀, p₁). The latter report pronounced differences in the angular distributions of the vector analyzing power of the two l_n = 1 transitions to ⁷Li*(0, 0.48). See also (1972FI1E, 1973FI1C). For reaction (b) see (1966FR06). See also ⁷Li and (1966AU1A, 1966BR25).

8. ⁶Li(d, d)⁶Li E_b = 22.282

The yield of elastically scattered deuterons has been measured for E_d = 2 to 4.8 MeV (1964PA06), 4.0 to 6.5 MeV (1966BR1J), and 6.33 to 7.14 MeV (1969BL14): no resonances are reported. At E_d = 12.0 MeV, θ_lab = 95°, the differential cross section for elastic scattering is 9.82 ± 0.20 mb/sr (1971BI11). See also ⁶Li and (1972FI1E, 1973FI1C).

9. ⁶Li(d, t)⁵Li Q_m = 0.59 E_b = 22.282

The cross section for tritium production rises rapidly to 190 mb at 1 MeV, then more slowly to 290 mb near 4 MeV. There is evidence of deviation from isotropy near 0.4 MeV (1955MA20). See also ⁵Li.

10. ⁶Li(d, ³He)⁵He Q_m = 0.90 E_b = 22.282

See ⁵He.

11. (a) ⁶Li(d, α)⁴He Q_m = 22.374 E_b = 22.282
(b) ⁶Li(d, αp)³H Q_m = 2.559
(c) ⁶Li(d, αn)³He Q_m = 1.795
(d) ⁶Li(d, 2d)⁴He Q_m = -1.4737

Cross sections and angular distributions (reaction (a)) have been measured for E_d = 0.03 to 12 MeV: see (1966LA04) and (1969LE22: E_d = 40 to 130 keV), (1966LO18: 0.2 to 2 MeV), (1968BE1P: 0.3 to 1.0 MeV), (1965RO1E, 1969DE31, 1969HU17: 0.35 to 1.50 MeV), (1966BR25: 1.0 to 2.0 MeV), (1964AN1A: 1.0 to 2.5 MeV), (1967CL06: 3 to 12 MeV) and (1969BL14: 6.33 to 7.14 MeV). Polarization measurements are reported at E_d = 0.40, 0.60, 0.80, 0.96 MeV (1971NE12, 1972SE09), 0.7 to 2.2 MeV (1967PL02), 2.1 to 10.9 MeV (1968DU07), 4.3, 6.3, 8.0, 10.1 and 11.8 MeV (1968BU13) and at E(⁶Li) = 0.6 MeV (1970HO11). See also (1967BU1B, 1972KO1P).

Maxima are observed at E_d = 0.8 MeV, Γ_lab ≈ 0.8 MeV and E_d = 3.75 MeV, Γ_lab ≈ 1.4 MeV (1963ME09, 1964PA06). Analysis of these and other data up to E_d = 12 MeV indicate a 2⁺, 0⁺, (6⁺), 2⁺, 4⁺ sequence of states: see Table 8.10 (in PDF or PS) in (1966LA04) (1965FR02, 1967CL06). See, however, reaction 4.

The assignment of J^π = 2⁺ to ⁸Be*(22.2) is consistent with the polarization information (1971NE12, 1972SE09), but the 0⁺ state may actually be virtual with respect to ⁶Li + d (1972SE09) [⁸Be*(20.3): see reaction 4 and (1972BA83)]. At E_d = 6.945 MeV, the α-yield shows an anomaly corresponding to ⁸Be*(27.48), the J^π = 0⁺; T = 2 analog of the ⁸He ground state (1969BL14). See also reaction 7 and (1969BA36; theor.).

See also (1966LE1C), (1971PL1C) and (1967TS1A, 1968CO1L, 1968KO1G, 1969CH1J, 1970FI11; theor.). For reactions (b), (c) and (d), see (1972HA34) and (1973FI04).

12. (a) ⁶Li(t, n)⁸Be Q_m = 16.024
(b) ⁶Li(t, n)⁴He⁴He Q_m = 16.116

For reaction (b) see (1966LA02, 1967BE13, 1967BI1D). See also (1966LA04).

13. (a) ⁶Li(³He, p)⁸Be Q_m = 16.788
(b) ⁶Li(³He, p)⁴He⁴He Q_m = 16.880

Proton groups are observed to ⁸Be*(0, 2.9, 16.63, 16.91, 17.64): see (1966LA04) and Tables 8.4 (in PDF or PS) and 8.5 (in PDF or PS). The excitation of ⁸Be*(18.15, 19.0, 19.4, 19.9) is also reported by (1971GL07). Angular distributions have been measured at E(³He) = 1.4 to 1.8 MeV (1969VI05; p₀, p₁) and 5, 6, 7, 9, 10, 13 and 17 MeV (1965FL03; p₀, p₁; PWBAE analysis). A gradual change is observed from a dominant back angle maximum to a dominant forward maximum (1965FL03). Measurements of the energies of all the particles emitted in this reaction and reactions 23, 38 and 42 show that the apparent width of ⁸Be*(2.9) does not depend on the relative velocity of the spectator particle: E_x = 2.83 ± 0.20 MeV, Γ = 1.75 ± 0.30 MeV (1969NU01). See also Table 8.4 (in PDF or PS).

Reaction (b) proceeds via ⁸Be*(16.63, 16.91): Γ = 117 ± 10 and 85 ± 10 keV, respectively. Interference effects are observed (1969VI05). See also ⁵Li and (1967RE03, 1968RE10, 1972TH08).

See also (1964MA57, 1968VI03, 1970GA1G, 1971TR1B), (1967HO1C) and (1967BA1E, 1968HE1F, 1969TH1D, 1970DE41, 1973ED02; theor.).

14. (a) ⁶Li(α, d)⁸Be Q_m = -1.5656
(b) ⁶Li(α, 2α)²H Q_m = -1.4737

Deuteron groups have been observed to ⁸Be*(0, 2.9, 11.3 ± 0.4) (1959ZE1A, 1962CE01). Angular distributions have been measured at E_α = 20 and 24 MeV (1973GR1N), 20.5 to 24.5 MeV and at 38 MeV (1965DE1F; d₀), 43 MeV (1959ZE1A; d₀, d₁) and 48 MeV (1962CE01; d₀, d₁). At E_α = 12 MeV (θ = 15° and 20°) the deuteron spectrum does not show a "ghost" anomaly at E_x = 0.1 - 0.5 MeV (1971BE52). A study of reaction (b) shows that the peak due to ⁸Be*(2.9) is best fitted by using Γ = 1.2 ± 0.3 MeV (1969BA18): see also Table 8.4 (in PDF or PS). See also (1968LA1E) and (1971BU1K; theor.). For reaction (b) see ⁶Li. See also (1966LA04).

15. (a) ⁶Li(⁶Li, α)⁸Be Q_m = 20.808
(b) ⁶Li(⁶Li, α)⁴He⁴He Q_m = 20.900

This reaction proceeds via ⁸Be*(0, 2.9, 16.6, 16.9, 22.5), and there is indication also that the direct three-body break-up (reaction (b)) is possible (1971GA1N, 1971GA21, 1972GA32: E_max(⁶Li) = 13.0 MeV). The involvement of a state at E_x = 19.9 MeV (Γ = 1.3 MeV) is suggested by (1966MA40). See also (1971GL07). Good agreement with the shapes of the peaks corresponding to ⁸Be*(16.6, 16.9) is obtained by using a simple two-level formula with interference, corrected for the effect of final state Coulomb interactions, assuming Γ(16.6) = 90 and Γ(16.9) = 70 keV: see also Table 8.5 (in PDF or PS) (1971NO04). See also (1968NO03, 1969IN06). The ratio of the intensities of the groups corresponding to ⁸Be*(16.6, 16.9) remains constant for E(⁶Li) = 4.3 to 5.5 MeV: I(16.6)/I(16.9) = 1.22 ± 0.08 (1966KI09, 1966MA40). Partial angular distributions for the α₀ group have been measured at fourteen energies for E(⁶Li) = 4 to 24 MeV (1970FR06). For reaction (b) see also (1966BE22).

For a review of the older work see (1966LA04). See also (1964MA26, 1967AL1F, 1967CH34, 1968DA20, 1971PO1D), (1966BR1G, 1967CA1D), (1966BA1T, 1966EL1A, 1966RO1E, 1966RO1F, 1966RO1H, 1972JO1D; theor.) and ¹²C.

16. ⁷Li(p, γ)⁸Be Q_m = 17.256

Cross sections and angular distributions have been reported from E_p = 30 keV to 18 MeV. Gamma rays are observed to the ground (γ₀) and to the broad, 2⁺, excited state at 2.9 MeV (γ₁) and to ⁸Be*(16.6, 16.9) (γ₃, γ₄). Resonances for both γ₀ and γ₁ occur at E_p = 0.44 and 1.03 MeV, and for γ₁ alone at 2, 4.9, 6.0, 7.3, and possibly at 3.1 and 11.1 MeV. In addition broad resonances are reported at E_p ≈ 5 MeV (γ₀), Γ ≈ 4 - 5 MeV, and at E_p ≈ 7.3 MeV (γ₁), Γ ≈ 8 MeV. The E_p ≈ 5 MeV resonance (E_x ≈ 22 MeV) represents the giant dipole resonance based on ⁸Be(0) while the γ₁ resonance, ≈ 2.3 MeV higher, is based on ⁸Be*(2.9). The γ₀ and γ₁ giant resonance peaks each contain about 10% of the dipole sum strength (1966FI1B, 1968BL1E, 1970FI1B). The main trend between E_p = 8 and 17.5 MeV is a decreasing cross section (1970FI1B). See, however, (1967FE04). See also Table 8.6 (in PDF or PS).

At the E_p = 0.44 MeV resonance (E_x = 17.64 MeV) the radiation is nearly isotropic consistent with p-wave formation, J^π = 1⁺, with channel spin ratio σ(J_c = 2)/σ(J_c = 1) = 3.2 ± 0.5 (1961ME10). Radiative widths for the γ₀ and γ₁ decay are displayed in Table 8.7 (in PDF or PS). The E2/M1 amplitude ratio for the 17.6 → 2.9 transition varies over the energy of the broad final state: the average value is δ = 0.21 ± 0.04 (1967CO19). See also (1967CO29).

⁸Be*(16.63, 16.91) are 2⁺ states with mixed T = 0, 1 isospin [see (1965MA1G, 1966MA03, 1968PA09, 1969SW01)], with the lower state of ⁷Li + p parentage and the higher of ⁷Be + n parentage (1965SW03, 1968PA09). A careful study of the α-breakup of ⁸Be*(16.63, 16.91) for E_p = 0.44 to 2.45 MeV shows that the non-resonant part of the cross section for production of ⁸Be*(16.63) is accounted for by an extranuclear direct-capture process. Resonances for production of ⁸Be*(16.63, 16.91) are observed at E_p = 0.44, 1.03 and 1.89 MeV [⁸Be*(17.64, 18.15, 18.9)]. The results are consistent with the hypothesis of nearly maximal isospin mixing for ⁸Be*(16.63, 16.91): decay to these states is not observed from the 3⁺ states at E_x = 19 MeV, but rather from the 2^- state at 18.9 MeV excitation (1969SW01). See also reaction 17. (1968PA09) find squared T = 1 components of 40% and 60% in ⁸Be*(16.6, 16.9) and of 95% and 5% in ⁸Be*(17.6, 18.2). Gamma - α angular correlation measurements at E_p = 0.44 MeV show that the 17.64 → 16.63 γ is nearly pure M1 δ(E2/M1) = -0.014 ± 0.013 (1969SW02). See also (1965SW03). Radiative widths are shown in Table 8.7 (in PDF or PS).

For a review of the earlier work, see (1959AJ76, 1966LA04). See also (1973SU1E), (1966EV1B, 1966PE1D, 1966WA1C, 1969KA1J), and (1973AS02; theor.).

17. ⁷Li(p, n)⁷Be Q_m = -1.64422 E_b = 17.256

Recent measurements of cross sections have been made for E_p = 1.9 to 2.36 MeV (1967BE61; σ_t), 1.93 to 2.66 MeV (1969LE23), 2.1 to 3.8 MeV (1971BU1D), 2.4 to 6.0 MeV (1972PR03; n₁γ), 2.6 to 5.4 MeV (1972EL19; n₀), 3 to 10 MeV (1966HA1J; n₁γ), 3.2 to 5.4 MeV (1972EL19; n₁), 23 to 52 MeV (1967LO07; n₁γ), and 30 and 50 MeV (1969CL06; n₀, n₁). See also (1973WA34). The shape of the neutron yield near threshold has been studied by (1966PA03). Polarization measurements are reported at E_p = 2.05 to 3.00 MeV (1973RO35, 1973RO2E), 3.0 to 4.0 MeV (1971HA27; n₀, n₁), 3.0 to 5.5 MeV (1971TH07; n₀, n₁) and 30 and 50 MeV (1969RO20). For a report on the earlier yield and polarization measurements, see (1966LA04). For angular distributions, see ⁷Be.

The yield of ground state neutrons (n₀) rises steeply from threshold and shows pronounced resonances at E_p = 2.25 and 4.9 MeV (1963BO06). The yield of n₁ also rises steeply from threshold (1964BU08) and exhibits a broad maximum near E_p = 3.2 MeV (1961BE05, 1972PR03) and a broad dip at E_p ≈ 5.5 MeV, also observed in the p₁ yield (1972PR03).

Multi-channel scattering length approximation analysis of the 2^- partial wave near the n₀ threshold indicates that the 2^- state at E_x = 18.9 MeV is virtual relative to the threshold and that its width Γ = 50 ± 20 keV (1974AR10). The ratio of the cross section for ⁷Li(p, γ)⁸Be*(18.9) γ / → ⁸Be*(16.6 + 16.9) [obtained by (1969SW01)] to the thermal neutron capture cross section ⁷Be(n, γ)⁸Be*(18.9) γ / → ⁸Be*(16.6 + 16.9) [obtained by (1973BA1J)], provides a rough estimate of the isospin impurity of ⁸Be*(18.9): σ_p,γ/σ_n,γ ≈ 1.5 × 10^-5 and therefore the T = 1 isospin impurity is < 4% in intensity (1974AR10).

The structure at E_p = 2.25 MeV is ascribed to a 3⁺, T = (1), l = 1 resonance with Γ_n ≈ Γ_p and γ²_n/γ²_p = 3 to 10: see (1966LA04). See also (1973RO35). At higher energies the broad peak in the n₀ yield at E_p = 4.9 MeV can be fitted by J^π = 3⁽⁺⁾ with Γ = 1.1 MeV, γ²_n ≈ γ²_p (1963BO06). The behavior of the n₁ cross section can be fitted by assuming a 1^- state at E_x = 19.5 MeV and a J = 0, 1, 2, positive-parity state at 19.9 MeV [presumably the 20.2 MeV state reported in reaction 4]. In addition the broad dip at E_p ≈ 5.5 MeV may be accounted for by the interference of two 2⁺ states (1972PR03). See Table 8.8 (in PDF or PS).

The ratio of the cross sections of the (p, n₁) reaction to ⁷Be*(0.43) to that for the (p, p₁) reaction to the analog state ⁷Li*(0.48) has been measured for E_p = 2.4 to 6.0 MeV (1972PR03), 3 to 10 MeV (1966HA1J) and 23 to 52 MeV (1967LO07). At the lower energies it deviates markedly from unity and varies strongly with energy (1966HA1J). At the higher energies the measurements seem to indicate that the spin-flip, isospin-flip part of the effective interaction is essentially independent of energy while the pure central part appears to decrease as the energy increases (1967LO07). See also (1969CL06).

See also (1968DA1H, 1970DA26, 1971JU05, 1971SC32, 1973AR1R, 1973NE1G), (1971WA1D) and (1970HO04, 1970LU1A, 1970RA33; theor.).

18. (a) ⁷Li(p, p)⁷Li E_b = 17.256
(b) ⁷Li(p, p')⁷Li*

Absolute differential cross sections for elastic scattering have been reported for E_p = 0.4 to 12 MeV (1953WA27, 1956MA12, 1965GL03), 14.5, 20.0 and 31.5 MeV (1956KI54) and more recently at 0.85 to 2.0 MeV (1966BA1Q), at 1.36 MeV (1969LE08) and at 6.868 MeV (1971BI11). The yield of inelastically scattered protons (p₁, to ⁷Li*(0.48)) and of 0.48 MeV γ-rays have been measured in the range E_p = 0.8 to 12 MeV (1951BR10, 1954KR06, 1954MO04, 1955HA34, 1957NE22, 1965GL03, 1966BA1Q, 1972PR03).

Polarization measurements are reported at E_p = 0.67 to 2.45 MeV (1973BR13; p₀), 2.7 to 10.6 MeV (1969KI04; p₀, p₁), 14.5 MeV (1965RO22; p₀), 49.8 MeV (1971MA13, 1971MA44; p₀, p₁), 152 MeV (1966RO1C; p₀) and 155 MeV (1968GE04; p₀, p₂). For earlier measurements see (1966LA04). For a summary of angular distribution studies see ⁷Li.

Anomalies in the elastic scattering appear at E_p = 0.44, 1.03, 1.88, 2.1, 2.5, 4.2 and 5.6 MeV. Resonances at E_p = 1.03, 3 and 5.5 MeV and an anomaly at E_p = 1.88 MeV appear in the inelastic channel. A phase shift analysis and a review of the existing cross section data by (1973BR13) show that the 0.44 and 1.03 MeV resonances are due to 1⁺ states which are a mixture of ⁵P₁ and ³P₁ with a mixing parameter of +25°; that the 2^- state at the neutron threshold (E_p = 1.88 MeV) has a width of about 50 keV [see also reaction 17]; and that the E_p = 2.05 MeV resonance corresponds to a 3⁺ state. The anomalous behavior of the ⁵P₃ phase around E_p = 2.2 MeV appears to result from the coupling of the two 3⁺ states [resonances at E_p = 2.05 and 2.25 MeV]. The ³S₁ phase begins to turn positive after 2.2 MeV suggesting a 1^- state at E_p = 2.5 MeV (1973BR13): see Table 8.9 (in PDF or PS) and (1972PR03).

An attempt has been made to find the T = 2 analog of the ground state of ⁸He: no resonances were observed in either the p₀ or the p₁ yield for E_p = 11.1 to 11.9 MeV (1968HA1H). Measurements of the intensity ratios of the reactions (p, p₁) and (p, n₁) have been made by (1966HA1J, 1967LO07, 1972PR03): see reaction 17.

See also (1967CA1G, 1972RU1C) and (1967JO01, 1967SA1C, 1969WA11; theor.).

19. ⁷Li(p, d)⁶Li Q_m = -5.026 E_b = 17.256

See (1969KO1P; theor.) and ⁶Li.

20. ⁷Li(p, t)⁵Li Q_m = -4.43 E_b = 17.256

See ⁵Li.

21. ⁷Li(p, α)⁴He Q_m = 17.348 E_b = 17.256

The cross section follows the expression E^-1e^{-B/√E (square
root of E)}, with B = 91.5 ± 4.5 keV^1/2, in the range E_p = 23 to 50 keV. The cross section in that interval rises from 0.013 to 2.4 μb (1967FI05). In the range E_p = 131 to 561 keV, the cross section increases from 0.16 ± 0.02 to 3.7 ± 0.4 mb (1971SP05; and T.A. Tombrello, private communication). The cross section has also been measured for E_p = 0.04 to 0.13 MeV by (1969LE22). Taking into account ⁸Be J^π = 2⁺ levels at 16.7, 16.9 and 20.6 MeV, (1972BA41) has made an R-matrix fit to the revised data of (1971SP05) and has obtained a quadratic energy dependence for the S-factor: S = 0.065[1 + 1.82E - 2.51E²] MeV · b, over the energy range E_p = 0 to 600 keV.

Excitation functions and angular distributions have been measured at many energies up to 18.6 MeV: see (1966LA04) for earlier references. Recently, differential cross-section measurements are reported by (1966MA03, 1969SW01: E_p = 0.4 to 2.45 MeV), (1969LE08: E_p = 1.36 MeV) and (1967CR05: E_p = 41.3 and 45.2 MeV). Polarization measurements have been carried out for E_p = 0.8 to 3 MeV (1968PE03), 2.7 to 10.6 MeV (1969KI04), 3.00 to 10.04 MeV (1968PL01), 5.5 to 6.7 MeV (1966BO09), and 7.4 to 10.4 MeV (1968AR04). See also (1966LA04) for a listing of the earlier references and (1966DA1B, 1971PL1C). In the range E_p = 3 to 10 MeV the asymmetry has one broad peak in the angular distribution at all energies except near 5 MeV; the peak value is 0.98 ± 0.04 at 6 MeV and is essentially 1.0 for E_p = 8.5 to 10 MeV (1968PL01, 1969KI04) [see Fig. 12 in (1969KI04) and Fig. 6 (1968PL01) for contour maps of the asymmetry].

Broad resonances are reported to occur at E_p = 3.0 MeV, Γ ≈ 1 MeV (1948HE01) and at E_p = 5.6 MeV, Γ ≈ 1 MeV (1961HA27 (and private communication), 1962TE04, 1964MA51). Some structure is also reported near E_p = 6.0 to 6.5 MeV, and at E_p = 9.0 MeV (1964MA51). The latter is also reflected in the behavior of the A₂ coefficient (1968PL01). The experimental data on yields and on polarization have been analyzed by (1970KU1H, 1971KU10): the data appear to require including two 0⁺ states [at E_x ≈ 19.7 and 21.8 MeV] with very small α-particle widths, and four 2⁺ states [at E_x ≈ 15.9, 20.1, 22.2 and 25 MeV]. See, however, reaction 4 and (1972BA83). A 4⁺ state near 20 MeV was also introduced in the calculation but its contribution was negligible. The observed discrepancies are said to be probably due to the assumption of pure T = 0 for these states (1971KU10).

See also (1968CO1L, 1968CO1M, 1970CO1M), (1969AU1C, 1972BA2M, 1973TR1E; astrophys. considerations), (1967BO38, 1969DA1G, 1970PE1D).

At E_p = 9.1 MeV, α-particle spectra are discussed in terms of the first excited state of ⁴He (1970LI06): see (1973FI04).

22. (a) ⁷Li(d, n)⁸Be Q_m = 15.031
(b) ⁷Li(d, n)⁴He⁴He Q_m = 15.1233

At E_d = 2 MeV, recoil proton spectra show only the ground state and ⁸Be*(2.9). No other groups with E_x < 9 MeV appear with intensity > 10% of n₀. The spectrum yields E_x = 3.1 ± 0.1, Γ = 1.75 ± 0.1 MeV (1964JO04) [(1971RO05) report E_x = 3.10 ± 0.09, Γ = 1.74 ± 0.08 MeV]. See Table 8.4 (in PDF or PS). At higher deuteron energies the population of ⁸Be*(16.6, 16.9, 17.6, 18.2, 18.9, 19.1, 19.2) is reported and l_p = 1 is obtained for the transitions to ⁸Be*(16.6, 17.6, 18.2): see (1960DI02, 1966DI1B, 1967KE1A, 1967KE1F). Angular distributions of the n₀ and n₁ groups to ⁸Be*(0, 2.9) are reported by (1966JU1A: E_d = 0.7 and 0.8 MeV), (1969NU1C: E_d = 0.90 to 1.09 MeV), (1966MI09: E_d = 1 MeV), and by (1970OSZY: E_d = 1.62 to 2.97 MeV). See also (1966LA04) for earlier references, (1966MA1J, 1966NU1B, 1966PO1D, 1968SA14, 1970SA20, 1970SA25, 1970SA29, 1973JO1L, 1973WE19) and the important theoretical paper by (1969BA43).

Reaction (b) appears to proceed primarily by sequential decay via ⁸Be*(2.9, 16.6, 16.9) and ⁵He(0): see (1967VA11). See also (1966AS04, 1966MI09, 1967JE01, 1972DE44, 1973HE26, 1973MC13). However, (1969HO11) deduce the involvement of a state with E_x = 11.4 ± 0.05 MeV, Γ_c.m. = 2.8 ± 0.2 MeV. See also (1973KA32). Attempts to observe n - α rescattering ("proximity scattering") proceeding via ⁸Be*(16.6, 16.9) have been unsuccessful: see (1968VA12, 1971SW10, 1972BR08). See also (1969TH02, 1971TH08) and the discussion in ⁵He.

For polarization measurements see ⁹Be. See also (1965LE12, 1967BE13, 1967BI1D, 1967FL12, 1967WI1C, 1969CO1F, 1971HU1H).

23. (a) ⁷Li(³He, d)⁸Be Q_m = 11.762
(b) ⁷Li(³He, pn)⁸Be Q_m = 9.538

Deuteron groups are observed to ⁸Be*(0, 2.9, 16.6, 16.9, 17.6). The group to ⁸Be*(2.9) is well fitted by E_x = 2.82 MeV, Γ = 1.27 MeV (1971PI06). See also reaction 13 (1969NU01). The J^π = 1⁺ mixed isospin state have E_x = 16.627 ± 0.005 and 16.901 ± 0.005 MeV and Γ = 113 ± 3 and 77 ± 3 keV (1967MA12): see also Table 8.5 (in PDF or PS) and (1971PI06). Angular distributions have been measured at E(³He) = 0.90 and 1.10 MeV (1971ST35; d₀), 3 MeV (1972LI31; d₀, d₁), and at 10 MeV by (1970DI12, 1970DI1F; d₀, d₁) and by (1968CO07; d to ⁸Be*(16.6, 16.9)). Spin-dependent effects in the angular distributions of d₀ and d₁ obtained by (1963WE1B) at 24.3 MeV are discussed by (1967SI1A). The angular distribution to ⁸Be*(16.6) is forward peaked, that for ⁸Be*(16.9) is roughly isotropic (1968CO07). See also (1964MA57).

The decay of various ⁹Be states to ⁸Be*(0, 2.9) has been studied by (1966CH20, 1968CO08, 1972MC1E): see ⁹Be and Table 9.5 (in PDF or PS). See also (1968LI1D, 1970LI1Q) and (1967CO1L; theor.).

24. (a) ⁷Li(α, t)⁸Be Q_m = -2.559
(b) ⁷Li(α, αt)⁴He Q_m = -2.4668

The angular distributions of the t₀ group have been measured at many energies up to 48 MeV: see (1966LA04). Recently, measurements have been carried out at E_α = 23.2 and 25.0 MeV (1972VA34; t₀, t₁), 30 MeV (1972ME07; t₀, t₁; PWBAE and DWBA analysis) and at 50 MeV (1970LA14; t₀). The ground state of ⁸Be does decay isotropically in the c.m. system and therefore J^π = 0⁺ (1970LA14). Spin-dependent effects in the angular distributions for t₀ and t₁ obtained by (1963WE1B: E_α = 28 MeV) are discussed by (1967SI1A). At E_α = 10 MeV an anomaly ("ghost") is observed in the ⁸Be excitation spectrum at E_x ≈ 0.5 MeV. It may be due to interference of the 0⁺ states ⁸Be*(0, 6.) [see reaction 4] or to thresholds of particle channels (1971BE52).

In reaction (b), sequential decay is observed at E_α = 50 MeV, via ⁸Be*(0, 2.9, 11.4, 16.6, 16.9, 19.9) (1970LA14). See also (1968BE1Q, 1968MA25).

25. ⁷Li(⁷Li, ⁶He)⁸Be Q_m = 7.278

At E(⁷Li) = 1.4, 1.7 and 1.8 MeV, the angular distributions of ⁶He ions leaving ⁸Be in its ground and 2.9 MeV states are essentially isotropic (1968ST12). See also (1966LA04).

26. (a) ⁷Be(n, p)⁷Li Q_m = 1.64422 E_b = 18.900
(b) ⁷Be(n, α)⁴He Q_m = 18.992
(c) ⁷Be(n, γα)⁴He Q_m = 18.992

At thermal energies, the (n, p) cross section is (4.8 ± 0.9) × 10⁴ b (1955HA34, 1973MU14), the (n, α) cross section is ≤ 0.1 mb (1962BA1B, 1963BA34) and the (n, γα) cross section is 155 mb (1963BA34). These values, and comparison of the (p, n) cross section with that of reaction (a), support the J^π = 3/2^- assignment for ⁷Be(0) (1957NE22, 1963BA34). The role of these reactions in astrophysical phenomena is discussed by (1968FOZY, 1969BA1N). See also (1959AJ76) and reaction 17.

27. ⁷Be(d, p)⁸Be Q_m = 16.676

For E_d = 0.8 to 1.7 MeV, proton groups are observing corresponding to the ground state and ⁸Be*(2.9): derived parameters for the latter are shown in Table 8.4 (in PDF or PS) (1959SP1A, 1960KA17). See also (1969BA43; theor.).

28. ⁸Li(β^-)⁸Be Q_m = 16.006

⁸Li decays mainly to the broad 2.9 MeV, 2⁺ level of ⁸Be, which decays into two α-particles. Both the β-spectrum and the resulting α-spectrum have been extensively studied. There appears to be an increasing excess of α-particles with E_α which may reflect transitions into the tail of the J^π = 2⁺ level at E_x = 16.67 MeV. See (1959AJ76, 1966LA04) for earlier references. See also (1969KL08) and ⁸B(β⁺).

Studies of the distribution of recoil momenta and neutrino recoil correlation indicate that the decay is overwhelmingly GT, axial vector [see reaction 1 in ⁸Li] and that the ground state of ⁸Li has J^π = 2⁺: see (1966LA04).

Angular correlations have been measured for the decays of ⁸Li and ⁸B as a test of the conserved vector current theory of β-decay. The values of the coefficients are displayed in Table 8.10 (in PDF or PS). See also (1973TR1J, 1973TR1K, 1973TR1L). The experimental value of δ [δ ≡ B(⁸Li) - B(⁸B)] is (5.4 ± 0.4)W_β, consistent with CVC theory (1966EI02).

A recent asymmetry measurement is reported by (1971VA19). See also (1971VA1E, 1973NE10). Measurements of the excitation spectra in the decays of ⁸Li and ⁸B show no evidence for second class currents: |g_IT| < 7 × 10^-4 (1971WI05). See also (1966JA1C) and (1960KU05, 1960WE1A, 1966BA26, 1966LI1C, 1968KR10, 1969BA43, 1970DA21, 1971LI1H, 1971WI18, 1971WI1C, 1972EM02, 1972HO23, 1972MI1M, 1972WI28, 1972WI1C, 1973EM1B, 1973HA49, 1973TO14, 1973WI11, 1974WI1L; theor.).

29. ⁸B(β⁺)⁸Be Q_m = 17.981

The decay proceeds mainly to ⁸Be*(2.9) [see Table 8.4 (in PDF or PS) for its parameters]. Detailed study of the high energy portion of the α-spectrum reveals a maximum near E_α = 8.3 MeV, corresponding to transitions to ⁸Be*(16.63), for which parameters E_x = 16.67 MeV, Γ = 150 to 190 keV or E_x = 16.62 MeV, Γ = 95 keV are derived. Using τ_1/2 = 769 ± 4 msec, log ft = 2.9. The low ft value supports the identification J^π = 2⁺; T = 1 for ⁸Be*(16.63) (1964MA35). See, however, (1965MA1G). The energy distribution of α-particles has also been measured by (1969CL10). Analysis of this data and of data from α - α scattering in a three level R-matrix formalism indicate a 2⁺ state of ⁸Be at E_x = 12.0^-3.0_+3.5 MeV and of Γ = 14^-3₊₄ MeV (a₂ = 6.0 ± 0.5 fm) (1969CL10). See also (1969BA43; theor.).

For angular correlation measurements see reaction 28 (1966EI02) and Table 8.10 (in PDF or PS). See also (1973TR1J, 1973TR1K, 1973TR1L).

30. (a) ⁹Be(γ, n)⁸Be Q_m = -1.6651
(b) ⁹Be(n, 2n)⁸Be Q_m = -1.6651
(c) ⁹Be(p, pn)⁸Be Q_m = -1.6651
(d) ⁹Be(t, tn)⁸Be Q_m = -1.6651
(e) ⁹Be(α, αn)⁸Be Q_m = -1.6651

For reaction (a) see (1966DE07, 1968AD09, 1969GA1M) and (1965BO1B, 1969AU05; theor.). See also ⁹Be.

Reaction (b) appears to proceed largely via excited states of ⁹Be, with subsequent decay to ⁸Be, mainly ⁸Be*(2.9): see (1966LA04), ⁹Be and ¹⁰Be. At E_n = 14 MeV the cross section at 20° for production of dineutrons is < 2 mb/sr (1966RO1G). See also (1965GO1C, 1965GO1E, 1966BO1C, 1966BO1F, 1966FE1C, 1967BO1F, 1969PR13).

For reaction (c) see (1966NO1A; theor.) and ⁹Be. For reaction (d) see (1967SE11). For reaction (e) see (1971GU15, 1973GE1J) and ⁹Be.

31. (a) ⁹Be(p, d)⁸Be Q_m = 0.5595
(b) ⁹Be(p, d)⁴He⁴He Q_m = 0.651
Q₀ = 559.0 ± 1.1 keV (1966RE02, 1967ST30);
Q₀ = 559.6 ± 0.6 keV (1967OD01); see also (1967SP09).

Angular distributions of deuteron groups have been reported at E_p = 0.11 to 0.55 MeV (1973SI27; d₀), 0.30 to 0.90 MeV (1968BE1N; d₀), 5 to 11 MeV (1972HU03; d₀) [analysis by DWBA and BHMM (1967BU23); derived spectroscopic factors], 13.0, 14.0, 15.0 and 21.35 MeV (1972VO1H; d₀), 17.0, 21.0, 25.0, 29.1 MeV (1973MO01; d₀, d₁), 33.6 MeV (1967KU10, 1970KU1D: deuterons to ⁸Be*(0, 2.9, 16.95, 17.62, 18.18, 19.21); also derived spectroscopic factors) [also saw ⁸Be*(11.4); determined Γ_c.m.(16.95) = 103 ± 15 keV, Γ_c.m.(19.21) = 208 ± 30 keV], 40.8 MeV (1966MA22: deuterons to ⁸Be*(16.63, 16.91)), 46 MeV (1967VE01: deuterons to ⁸Be*(0, 2.9, 16.9, 17.6, 18.2, 19.1) [also report ⁸Be*(24.5)], 100 MeV (1968LE01: deuterons to ⁸Be*(0, 2.9, 16.9, 18.9)) [also saw ⁸Be*(11.0, 23.0, 26.0)], 155 MeV (1969BA05, 1969TO1A: deuterons to ⁸Be*(0, 2.9) [Γ = 2.0 ± 0.1 MeV], 11.5 [Γ = 8 ± 1 MeV], 16.8 ± 0.2, 18.9 ± 0.3) [also saw ⁸Be*(17.6 ± 0.4, 21.5 ± 0.3)] and 185 MeV (1969SU02: deuterons to ⁸Be*(0, 2.94 ± 0.08, 11.3 ± 0.3, 16.87 ± 0.06, 17.58 ± 0.08, 18.10 ± 0.10, 19.16 ± 0.07, 22.0 ± 0.15, 22.9 ± 0.15)) [also report ⁸Be*(20.0 ± 0.2 (?)); Γ_c.m.(2.9) = 1.5 ± 0.1 MeV; Γ_c.m.(22.0, 22.9) ≥ 1 MeV (the angular distributions for these two states are not clear cut)]. (1971SC26) have analyzed the angular distributions obtained by (1967VE01, 1968LE01) using DWBA with a local-energy approximation and have derived spectroscopic factors. With the exception of ⁸Be*(11.4, 22.0, 22.9) the angular distributions are consistent with l = 1. The yield of the deuterons corresponding to ⁸Be*(16.63) is very low: [≈ 5% compared to ⁸Be*(16.91)] as expected by predictions of the cluster model (1966MA22: E_p = 40.8 MeV). See also (1967KU10) and reaction 21 in ⁹Be in (1966LA04).

Anomalies in the deuteron spectrum between the d₀ and the d₁ groups have been reported at various energies [see (1966LA04) and (1967FI1D, 1967HA1K, 1971BE52, 1971MI1C)]. The shape of the deuteron spectrum near ⁸Be*(2.9) requires a₂ ≈ 7.1 fm (1969BA43). See also reaction 4 and (1968BA2D). At E_p = 17 MeV, for the transitions to ⁸Be*(0, 2.9) the ratios of σ(p, d)/σ(p, d) = 11.8 and 14.1, respectively (1967CO09, 1969CO06). See also (1968NA1A; theor.).

Reaction (b) at E_p = 9 MeV is dominated by strong final state interactions through ⁸Be*(0, 2.9) and ⁶Li*(2.19) with little or no yield from a direct three-body decay (1971EM01). See also (1967FI1D). See also ¹⁰B and (1966CA1E, 1966LA20, 1967OG1A, 1967RO07, 1968TI1A, 1972QU01) and (1967BA1M, 1967JO1D, 1968BO1P, 1970BO1K; theor.).

32. (a) ⁹Be(d, t)⁸Be Q_m = 4.5925
(b) ⁹Be(d, t)⁴He⁴He Q_m = 4.684
Q₀ = 4591.7 ± 3.1 keV (1967OD01: see also (1967SP09)).

At E_d = 11.8 MeV, angular distributions have been obtained for the tritons to ⁸Be*(0, 2.9) (1967FI07): S = 0.51 and 0.75, respectively (DWBA analysis). At E_d = 38 MeV, angular distributions of the tritons to ⁸Be*(16.91, 17.64, 19.0) have been compared with those of the ³He to the analog states in ⁸Li. The cross-section ratios σ_17.64/σ_0.98(⁸Li) = 0.45 ± 0.04 and σ_16.91/σ_0(⁸Li) = 0.75 ± 0.04, consistent with the pure T = 1 nature of ⁸Be*(17.64) and the mixed T nature of ⁸Be*(16.91) [and ⁸Be*(16.63)] (1966GA21; abstract). Angular distributions have also been measured at E_d = 0.3 to 1.0 MeV (1968BE1E; t₀), 0.9 to 3.1 MeV (1973SA1Q; t₀), 15.0 MeV (1969AR1B; t₀) and at many other energies up to E_d = 20 MeV: see (1966LA04). The ghost anomaly which is seen near the t₀ group has been studied at E_d = 2.5 MeV: it is interpreted as being due to an extreme threshold effect (1971BE52). See also (1967DE1J) and (1970BO1K, 1973HE1J; theor.). A kinematically complete study of reaction (b) at E_d = 26.3 MeV indicates the involvement of ⁸Be*(0, 2.9, 11.4, 16.9, 19.9 + 20.1). Parameters obtained for ⁸Be*(2.9, 11.4) are E_x = 3.20 ± 0.03 and 11.70 ± 0.07 MeV, Γ = 1.72 ± 0.09 and 4.41 ± 0.5 MeV (1973SO08).

33. (a) ⁹Be(³He, α)⁸Be Q_m = 18.9134
(b) ⁹Be(³He, α)⁴He⁴He Q_m = 19.005
(c) ⁹Be(³He, αp)⁷Li Q_m = 1.657

Angular distributions have been measured at E(³He) = 3.0 MeV (1968MO05; α_16.91), 3.0 and 4.0 MeV (1963DO08; α₀, α_2.9, α_16.6, α_16.9, α_17.6), 18.0, 22.7, 26.7, 32.3 MeV (1965AR07; α₀, α₁) and 26.7 MeV (1968AR12; α_16.9, α_17.6, α_18.1, α_19.2). See also (1959AJ76) and (1967SI1A). The parameters of the observed states are shown in Tables 8.4 (in PDF or PS) and 8.5 (in PDF or PS) (1961ER01, 1963DO08).

Reaction (b) has been studied at E(³He) = 1.6 MeV (1970EH1A), 3.0 MeV (1966SU04, 1968MO05) and 3.0 and 4.0 MeV (1972TA04). See also (1966LA04) and (1967ST1E). The reaction proceeds by sequential decay via ⁸Be*(0, 2.9, 11.4, 16.6, 16.9, 19.9, 22.5) (1972TA04). The angular correlation via ⁸Be*(16.91) is consistent with J^π = 2⁺ for that state (1968MO05). J^π = 2⁺ is also indicated for ⁸Be*(16.63) (1966SU04). See also (1968TH1G). For reaction (c) see (1967ST1D). See also (1964MA57, 1966CA08, 1966DI1C, 1967OG1A, 1970CA28, 1971TR1B, 1972RO1N), (1967HO1C) and (1970BO1K, 1971OS05, 1972TH04, 1973RO28; theor.).

34. (a) ⁹Be(⁶Li, ⁷Li)⁸Be Q_m = 5.586
(b) ⁹Be(⁷Li, ⁸Li)⁸Be Q_m = 0.368
(c) ⁹Be(¹²C, ¹³C)⁸Be Q_m = 3.281
(d) ⁹Be(¹⁶O, ¹⁷O)⁸Be Q_m = 2.477
(e) ⁹Be(¹⁸O, ¹⁹O)⁸Be Q_m = 2.292
(f) ⁹Be(¹⁹F, ²⁰F)⁸Be Q_m = 4.936

At E(⁶Li) = 3.5 MeV the population of ⁸Be*(2.9) is very small but ⁸Be_g.s. is involved (1968JA08). See also (1966LA04). For reaction (b) see (1966LE10) and (1968TO1C; theor.). For reaction (c) see (1970BA1J, 1970BA1Y). For reaction (d) see (1968KN1A, 1970BA1J, 1970BA1Y). Reaction (e) has been studied at E(¹⁸O) = 16 and 20 MeV (1971KN05). See also (1968FA04). For reaction (f) see (1968FA04).

35. ¹⁰B(γ, d)⁸Be Q_m = -6.0258

See ¹⁰B and (1959AJ76).

36. (a) ¹⁰B(n, t)⁸Be Q_m = 0.2318
(b) ¹⁰B(n, t)⁴He⁴He Q_m = 0.3237

Angular distributions have been measured at E_n = 14.4 MeV (1964VA14; t₀, t₁). Reaction (b) has been studied at the same energy by (1967VA12). See also (1971MI1H) and (1967BA1E; theor.). See also ¹¹B in (1975AJ02).

37. (a) ¹⁰B(p, ³He)⁸Be Q_m = -0.5320
(b) ¹⁰B(p, pd)⁸Be Q_m = -6.0258

At E_p = 49.5 MeV angular distribution measurements have been carried out for the ³He groups to ⁸Be*(0, 2.9, 16.6, 16.9): the ratio dσ(16.63)/dσ(16.91) has a mean value of 0.65 ± 0.05 for θ = 15° to 30°, suggesting possibly a preferential excitation of the T = 1 components of these two states. The ratio of the differential cross sections dσ(p, t) [to ⁸B_g.s.] to dσ(p, ³He) [to ⁸Be*(16.63, 16.91)] (15° to 30°) seems to also suggest this (1971SQ01).

38. (a) ¹⁰B(d, α)⁸Be Q_m = 17.822
(b) ¹⁰B(d, α)⁴He⁴He Q_m = 17.9138
Q₀ = 17.8186 ± 0.0041 (1967OD01).

Angular distributions have been reported at E_d = 0.5 to 1.0 MeV (1968FR07; α₀, α₁), 0.8 to 2.5 MeV (1968CO31; α₀, α₁), 3.0 to 7.2 MeV (1967LE1C; α₀) and 7.5 MeV (1966BR08; α to ⁸Be*(16.63, 16.91, 17.64, 18.15)). At E_d = 7.5 MeV the total cross section for formation of ⁸Be*(16.63), σ_t(16.63), is about 1.15 σ_t(16.91), consistent with the mixed isospin character of these two states. σ_t(18.15) is ≈ 0.85 σ_t(16.91), but the other nearby 1⁺ state ⁸Be*(17.64) has σ_t(17.64) ≈ 0.07 σ_t(16.91), consistent with the nearly pure T = 1 nature of ⁸Be*(17.64) (1966BR08). These four states [⁸Be*(16.63, 16.91, 17.64, 18.15)] have been studied for E_d = 4.0 to 12.0 MeV. Interference between the 2⁺ states [⁸Be*(16.63, 16.91)] varies as a function of energy. The cross section ratios for formation of ⁸Be*(17.64, 18.15) vary in a way consistent with a change in the population of the T = 1 part of the wave function over the energy range: at the higher energies, there is very little isospin violation. At higher E_x only the 3⁺ state at E_x = 19.2 MeV is observed, the neighboring 3⁺ state at E_x = 19.06 MeV is not seen. The J^π = 1⁺; T = 0 state is found to have E_x = 18.146 ± 0.005 MeV (based on 17.638 for the J^π = 1⁺; T = 1 state) and Γ = 138 ± 6 keV (1970CA12). There is some question as to whether a two-level fit can be made for the α groups to ⁸Be*(16.63, 16.91). ((1970CA12) and W.D. Callender, private communication) are dubious about this, feeling that other 2⁺ states have to be brought into the calculation. Based on a two-level fit they find the following average values: Γ_16.6 = 113 keV, Γ_16.9 = 80 keV, ΔQ = 302 keV. However, (1971NO04) state that the two-level fit is appropriate if the spectra are properly corrected for effects of final state Coulomb interactions: Γ_16.6 = 90 ± 5 keV, Γ_16.9 = 70 ± 5 keV, ΔQ = 290 ± 7 keV. See also (1966BR22) and (1970KI1D; theor.). For a listing of the parameters of observed states see Tables 8.4 (in PDF or PS) and 8.5 (in PDF or PS) (1961ER01, 1969NU01, 1970CA12).

Angular correlation studies [E_d ≤ 3 MeV] indicate that reaction (b) takes place mainly by a sequential process involving ⁸Be*(0, 2.9, 11.4, 16.6, 16.9): see (1968LO01, 1970ST02, 1971LA14) and (1967CA13, 1968AS01). (1968LO01) report E_x = 2.7 ± 0.2 MeV, Γ = 1.0 ± 0.1 MeV, and Γ = 3.0 ± 0.5 MeV for ⁸Be*(11.4). See also (1967CA13, 1970ST02). For a study of rescattering effects see (1972VA1L).

See also ¹²C and (1964MA57, 1965PA1E, 1966AS10, 1966DI1C, 1967AS1A, 1967NA11, 1967PE1B, 1968TH1G, 1969NA17, 1972RO1N), (1966BR1G) and (1967BA1M, 1968NA1B, 1970KO01, 1970NA06, 1973RO28; theor.).

39. ¹⁰B(³He, pα)⁸Be Q_m = 12.328

At E(³He) = 2.45 and 6.00 MeV this reaction proceeds primarily by sequential decay via ⁸Be*(0, 2.9) and via ⁵Li, ⁹B and ¹²C states [see also the latter nuclei] (1966WA16). See also (1966WI08, 1968KR02, 1970BE1F), (1966LA04, 1967HO1C) and (1967PR1B; theor.).

40. ¹⁰B(α, ⁶Li)⁸Be Q_m = -4.552

At E_α = 46 MeV angular distributions obtained for the transitions to ⁸Be*(0, 2.9) are consistent with a direct interaction mechanism (1970ZE03).

41. (a) ¹¹B(γ, t)⁸Be Q_m = -11.2242
(b) ¹¹B(γ, t)⁴He⁴He Q_m = -11.1323

See ¹¹B in (1975AJ02).

42. (a) ¹¹B(p, α)⁸Be Q_m = 8.591
(b) ¹¹B(p, α)⁴He⁴He Q_m = 8.6824
Q₀ = 8.575 ± 0.011 (1967SP09).

Angular distributions have been measured at E_p = 0.78 to 12.00 MeV (1963SY01, 1968WA1G; α₀), 1.4, 2.0 and 2.6 MeV (1972GE19; α₀, α₁ (not at 2.0)), 12, 20, 24 and 30 MeV (1971CA16; α₀), 26.7 and 38 MeV (1969GA03, 1970GU06; α₀), 40 MeV (1971KA21; α₀, α₁ and α to ⁸Be*(12.5) [Γ = 4.0 ± 0.5 MeV] and to ⁸Be*(16.6 + 16.9, 17.6, 18.1, 19.0)) and at E_p = 45 MeV (1971DE2B, 1972DE01, 1972DE02; α₀, α₁). At E_p = 45 MeV the angular distributions are typical of a direct reaction mechanism, with a rise in the backward direction indicative of heavy particle stripping (1972DE01, 1972DE02). Observed parameters for ⁸Be*(2.9) are shown in Table 8.4 (in PDF or PS) (1969NU01, 1971KA21). At E_p = 40 MeV, θ = 20°, dσ_16.6/dσ_16.9 = 2.3 ± 0.4 (1971KA21).

Reaction (b) has been studied for E_p = 0.15 to 9.5 MeV. The reaction proceeds predominantly by sequential two-body decay via ⁸Be*(0, 2.9): see, e.g., (1965BR18, 1968CH01, 1972HU04). See also (1967KA09, 1967MA11, 1968GI03, 1969QU01, 1970CO03, 1971KO22, 1972MI1J). Some papers report very narrow widths in this reaction for ⁸Be*(2.9). However, (1972HU04) find a good fit to the data with E_x = 2.99 MeV, Γ = 1.45 MeV when an interference term is included. The interference effect is attributable to the identity of the three α-particles and to the ambiguity in their order of emission (1965BR18).

See also ¹²C in (1968AJ02, 1975AJ02), (1966LA04), (1966LO1G, 1967CO29, 1967EN1A, 1967FL12, 1967TR1B, 1968LA1C, 1969LA1B, 1969TR1D, 1972DZ10, 1973PR1C), (1969PH1B) and (1969GO13, 1970GO1J, 1970GO33, 1970GO49, 1970KO1K, 1970MC25, 1970MC1T, 1970SC01, 1972TH1M, 1973DU1D, 1973GO35; theor.).

43. ¹¹B(d, nα)⁸Be Q_m = 6.3658

See (1971RE19) and ⁹Be.

44. ¹¹B(³He, ⁶Li)⁸Be Q_m = 4.570

This reaction has been studied for E(³He) = 1.4 to 5.8 MeV. Angular distributions have been measured at E(³He) = 5.2 MeV involving ⁸Be_g.s. + ⁶Li_g.s., ⁸Be_g.s. + ⁶Li^*_3.56, and ⁸Be^*_2.9 + ⁶Li_g.s. (1967YO02, 1967YO1C, 1968ME13).

45. (a) ¹¹B(α, ⁷Li)⁸Be Q_m = -8.758
(b) ¹¹B(α, ⁷Li)⁴He⁴He Q_m = -8.666

Angular distributions have been reported at E_α = 28.4 and 29.0 MeV for ⁸Be_g.s. + ⁷Li_g.s., ⁸Be_g.s. + ⁷Li^*_0.48 and ⁸Be^*_2.9 + ⁷Li (29 MeV only) by (1968KA24) and at 42 MeV for ⁸Be_g.s. + ⁷Li_g.s. and ⁸Be_g.s. + ⁷Li^*_0.48 by (1968MI05). At E_α = 65 MeV ⁸Be*(16.6 + 16.9, 20.0) are apparently also excited (1973WO06). See also (1966GE12) and ⁷Li. For reaction (b) see (1969FU09).

46. (a) ¹²C(γ, α)⁸Be Q_m = -7.367
(b) ¹²C(e, eα)⁸Be Q_m = -7.367

For reaction (a) see (1966LA04), (1973CL1E) and (1965DZ1A; theor.). For reaction (b) see (1970EN1A).

47. ¹²C(n, nα)⁸Be Q_m = -7.367

This reaction proceeds via ⁸Be*(0, 2.9) at E_n = 13 to 18 MeV, and via states in ⁵He, ⁹Be and ¹²C (1966MO05). See also (1966LA04) and (1971DO1K).

48. ¹²C(p, pα)⁸Be Q_m = -7.367

This reaction has been studied for 13 ≤ E_p ≤ 160 MeV. At low energies it involves ⁸Be(0); at higher energies ⁸Be*(0, 2.9) (1966RO1D, 1967GA01, 1969LU1B, 1970GO12, 1970KE1B, 1972MA62). It is not clear whether higher states are also involved: see (1970KE1B). See also (1966LA04) and (1966JA1B, 1968YA1C, 1972YA1B).

49. ¹²C(d, ⁶Li)⁸Be Q_m = -5.893

Angular distributions have been determined at E_d = 19.5 MeV (1971GU07), 28 MeV (1972BE1T, 1972BE29: ⁸Be(0)) and 51.8 MeV (1970EI05: both ⁸Be*(0, 2.9)). At E_d = 28 MeV a structure is observed which is attributed to the process ¹²C(d, α)¹⁰B → α + ⁶Li (1972CO23). At E_d = 55 MeV the population of ⁸Be*(11.4, 16.6 + 16.9) is also reported (1971MC04). See also (1966DA1C, 1970AN1E), (1967OG1A, 1972GA1E) and (1968RO1D, 1970EL1F, 1971DR02, 1973HE1J; theor.). See also ¹²C and (1966LA04).

50. ¹²C(³He, ⁷Be)⁸Be Q_m = -5.780

Angular distributions have been measured for the transitions to ⁷Be_g.s. + ⁸Be_g.s. and ⁷Be^*_0.43 + ⁸Be_g.s. at E(³He) = 25.5 to 29 MeV (1972PI1A, 1973PI1B, 1973PI1D), 28 MeV (1970DE12, 1973KL1B) and at 35.7 MeV (1969ZE1A, 1970FO1D). The transitions to ⁷Be_g.s.+0.43 + ⁸Be^*_2.9 have also been studied by (1970DE12). See also (1967ZA1B, 1973ST1N) and (1969NE1D; theor.).

51. (a) ¹²C(α, 2α)⁸Be Q_m = -7.367
(b) ¹²C(α, ⁸Be)⁸Be Q_m = -7.4587

This reaction has been studied up to E_α = 104 MeV. At E_α = 25 MeV it involves ⁸Be(0) (1966BO28); at E_α = 28.0, 37.4, 70, 90 and 104 MeV, the reaction goes via ⁸Be*(0, 2.9) (1965YA02, 1967TA1C, 1968YA02, 1971BR1G, 1972SH1J) and at 90 MeV it may, in addition, involve the broad 4⁺ state at 11.4 MeV (1970JA06). See also (1966LA04) and (1965KU1B, 1967ME1C; theor.).

Reaction (b) has been studied for 11.9 ≤ E_α ≤ 19.4 MeV and angular distributions are reported for E_α = 12.70 to 16.25 MeV (1967CH21) and 65 MeV (1973WO06: ⁸Be*(0, 2.9)). See ¹⁶O in (1971AJ02).

52. ¹²C(¹²C, ¹⁶O)⁸Be Q_m = -0.2051

Angular distributions have been measured for E(¹²C) = 11.6 to 13.4 MeV (1972CO1H). At E(¹²C) = 50 to 65 MeV the population of ⁸Be*(0, 2.9) is reported by (1972FL1C). See also (1968JA1F, 1970JA1B, 1972GR1T, 1973CR1A, 1973SC1J).

53. ¹²C(¹⁴N, ¹⁸F)⁸Be Q_m = -2.951

See (1965WI1A).

54. ¹²C(¹⁶O, ²⁰Ne)⁸Be Q_m = -2.637

See (1972GR1Q).

55. ¹³C(p, ⁶Li)⁸Be Q_m = -8.615

Angular distributions have been measured at E_p = 45 MeV for the transitions to ⁸Be*(0, 2.9) (1971BR07).

56. ¹³C(d, ⁷Li)⁸Be Q_m = -3.589

Angular distributions are reported at E_d = 14.6 MeV for the transitions to ⁸Be_g.s. + ⁷Li_g.s. and ⁸Be_g.s. + ⁷Li^*_0.48 (1967DE03).

57. ¹³C(³He, ⁸Be)⁸Be Q_m = 8.173

Angular distributions have been obtained at E(³He) = 3.3, 5.0 and 5.8 MeV for the transition to ⁸Be_g.s. + ⁸Be_g.s. (1968JA07, 1969JA1L). See also ¹⁶O in (1971AJ02) and (1967SA1E).

58. (a) ¹⁴N(n, ⁷Li)⁴He⁴He Q_m = -8.823
(b) ¹⁴N(n, t)⁴He⁴He⁴He Q_m = -11.290

See (1967MO21, 1971SC16) and ⁷Li.

59. ¹⁴N(¹⁰B, 6α) Q_m = 0.366

See (1965SH11, 1966SH1E).

60. ¹⁶O(γ, 2α)⁸Be Q_m = -14.528

See (1966LA04) and ¹²C in (1968AJ02).

61. ¹⁶O(p, p)⁴He⁴He⁴He⁴He Q_m = -14.436

See (1961KO02, 1962VA1A) and ¹⁶O in (1971AJ02).

62. ¹⁶O(α, ¹²C)⁸Be Q_m = -7.2535

Angular distributions have been measured at E_α = 65 MeV involving ⁸Be_g.s. and ¹²C*(0, 4.4) (1973WO06). See also (1968PA12) and ¹⁶O in (1971AJ02) and ²⁰Ne in (1972AJ02).

63. ¹⁶O(¹⁰B, 6α) Q_m = -7.234

See (1965SH11).

64. ¹⁹F(p, ¹²C)⁸Be Q_m = 0.861

See (1969GO1B, 1971GO1U) and ²⁰Ne in (1972AJ02).

65. ²⁰Ne(α, ¹⁶O)⁸Be Q_m = -4.822

This reaction has not been observed: see (1962LA15).