(See Energy Level Diagrams for 7Li)
Cluster and α-particle models: (1978MI13, 1979MA11, 1979VE08, 1980KA16, 1980SU04, 1981BE27, 1981EL06, 1981FI1A, 1981HA1Y, 1981KR1J, 1981RA1M, 1981SR01, 1982DE12, 1982FI13, 1982MU10, 1983DU1B, 1983KA1K).
Astrophysical questions: (1978BU1B, 1978CA1C, 1978DW1A, 1978HA1E, 1978OR1A, 1978ST1C, 1978ST1D, 1979BA1P, 1979MA1F, 1979MC1A, 1979MO04, 1979RA1C, 1979RO1A, 1979WI1D, 1979YA1C, 1980CA1C, 1980CO1R, 1980FR1G, 1980LA1G, 1980RE1B, 1980SC1K, 1981AU1D, 1981AU1G, 1981GA1C, 1981SC1M, 1982BA80, 1982PA1G, 1982SP1B).
Complex reactions involving 7Li: (1978BH03, 1978DU1B, 1978HE1C, 1978KN1C, 1979AL22, 1979DY01, 1979GA04, 1979GE1A, 1979GO11, 1979LO11, 1979MO22, 1979SC08, 1979SC1D, 1979ST1D, 1979VI05, 1979WE06, 1980BO31, 1980GR10, 1980GU1E, 1980ME1F, 1980MI01, 1980MO28, 1980ST06, 1980WI1L, 1980ZU01, 1981BH02, 1981BL1G, 1981BO1X, 1981CH18, 1981CI03, 1981EG1E, 1981HN02, 1981ME13, 1981MO20, 1981MU10, 1981PH1D, 1981TA22, 1981ZU1B, 1982BO1J, 1982BO1Q, 1982BO35, 1982BO1Y, 1982DE1Y, 1982FU04, 1982GL01, 1982GO1E, 1982GU1H, 1982JA1C, 1982LU01, 1982LY1A, 1982MO13, 1982MO1N, 1982MU10, 1982NI03, 1982OH09, 1982WU1B, 1983FU04, 1983KW01, 1983MO03, 1983SA06, 1983TH04).
Pion capture and reactions involving pions: (1978DY01, 1978ER1A, 1978FU09, 1978KI13, 1978KN1C, 1978SI1D, 1979AK02, 1979AL1J, 1979BA17, 1979BA1M, 1979BO1F, 1979BO1G, 1979BO23, 1979CO1C, 1979DO17, 1979EN1C, 1979IN1A, 1979KI1G, 1979MA02, 1979ME07, 1979MI1C, 1979NA04, 1979PE1D, 1979RE1A, 1979SI16, 1979TI1A, 1980BA27, 1980BO03, 1980ER01, 1980JO06, 1980JO1D, 1980KA11, 1980LE02, 1980PE1C, 1980SA04, 1980SC24, 1980WH1A, 1981AS07, 1981BE63, 1981BE13, 1981BL1F, 1981DU1H, 1981EV01, 1981HE1H, 1981IO01, 1981IS11, 1981OS04, 1981SE1H, 1981SE11, 1981SE1B, 1981SI1D, 1981WH01, 1981WH1C, 1981WH1D, 1982AL31, 1982AP1A, 1982BL1G, 1982DO02, 1982IS10, 1982LEZY, 1982OS01, 1982RI1A, 1982SE08, 1982WA1G, 1982WH1A, 1983HU02, 1983IRZZ, 1983PIZW, 1983RI1C, 1983SEZV).
Hypernuclei: (1978DA1A, 1978PO1A, 1978SO1A, 1979GA1D, 1979GA1E, 1980AU1C, 1980GA1P, 1980IW1A, 1981BE45, 1981BE17, 1981BO09, 1981DA1C, 1981WA1J, 1982DEZQ, 1982DO1M, 1982ER1B, 1982ER1E, 1982JO1C, 1982KO11, 1982MA1Y, 1982MO1Q, 1982PI1J, 1982RA1L, 1983JO1E).
Ground-state properties of 7Li: (1978HE1D, 1980BO1N, 1980KA16, 1980SU04, 1981BE27, 1981BO1Y, 1981EG1E, 1981EL06, 1981HN02, 1981MO08, 1981RA1M, 1981SA16, 1981SR01, 1982BA2G, 1982DE35, 1982FIZY, 1982FI13, 1982HN1A, 1982MO13, 1982MU10, 1982NG01, 1982PE06, 1983DU1B).
Excitation functions and angular distributions have been studied for Eα = 0.5 to 1.9 MeV. The cross section rises smoothly as expected for a direct-capture process: see (1966LA04). For calculations of the low-energy S-factor see (1981WI04). See also (1979YA1C; astrophysics).
The cross section for this reaction has been measured for Eα = 11 to 18 MeV: the data show the effect of 7Li*(7.46) and indicate a broad resonance near Eα = 16.8 MeV [7Li*(9.6)]. The level parameters derived from this reaction and from reaction 3 are displayed in Table 7.3 (in PDF or PS). The yield of 6Li ions at 0° (lab) has also been measured for Eα = 11.310 to 11.930 MeV with 2 - 3% accuracy: the data were then reduced to obtain the cm differential cross sections at 0° and 180° for the inverse reaction in the energy region corresponding to formation of 7Li*(7.46) (1977BR21). See also (1977KN1A).
The excitation curves for the elastic scattering show the effects of 7Li*(4.63, 6.68, 7.46, 9.67). The derived level parameters are displayed in Table 7.3 (in PDF or PS). Angular distributions have been studied for Eα = 2.13 to 2.98 MeV [see (1979AJ01)] and Epol. t = 6.0 to 17 MeV (1977BR21, 1980JA1F, 1981JA1G; very accurate σ(θ)). Analyzing power measurements are reported for Epol. t = 6.0 to 17 MeV (1976HA17, 1980JA1F, 1981JA1G): a polarization extremum (Ay = -1) occurs near Et = 11.1 MeV, θc.m. = 95°. There is some suggestion for a Jπ = 1/2- state in 7Li at Ex = 9.6 MeV (1981JA1G; N. Jarmie, private communication): see also reaction 7. The breakup of 7Li [at kinematic energy of 70 MeV] into α + t proceeds sequentially via 7Li*(4.63) when 12C is bombarded. When 208Pb is hit by 7Li, both this sequential process and breakup in the nuclear field of the 208Pb nucleus appear to occur (1981SH01). See also (1977KN1A, 1978BR1A) and (1977HA1E, 1978MI13, 1978TA1A, 1978TH1A, 1979LE1B, 1979WI1B, 1981AO02, 1981BE01, 1981FR1N, 1982FU01, 1982KA11, 1983AO03; theor.).
Angular distributions have been reported at Eα = 39.9 to 49.5 MeV (p0, p1) and 60.2, 92.4 and 140.0 MeV (p0+1) [see (1979AJ01)] and at Eα = 37.5 to 43.0 MeV (1982SL01; p0, p1). See also (1978GL03, 1979AL1F), (1982RA1M; astrophys.) and 8Be.
The thermal capture cross section is 38.5 ± 3.0 mb (1981MUZQ). Gamma rays are observed corresponding to transitions to 7Li*(0, 0.48) with branching ratios of (61 ± 3) and (39 ± 2)%. 7Li*(4.63) is not involved in the decay [≲ 2%]: see (1979AJ01). See also (1980BA34; theor.).
The scattering amplitude (bound) a = 2.2 ± 0.25i fm, σfree = 0.45 ± 0.08 b. The thermal scattering cross section = 0.75 ± 0.02 b (1981MUZQ). The total cross section has been measured from En = 4 eV to 49.6 MeV [see (1976GAYV)]. Recent measurements include those of (1982SM02: En = 0.1 to 0.8 MeV) and (1979LA1D, 1980KE1L,; En = 2.99 to 49.64 MeV) and the integrated cross sections of (1979KN01; n0; 4.1 to 7.5 MeV) and (1979HO11; n0 and n1; 7.47 to 13.94 MeV). A pronounced resonance occurs at En = 244.5 ± 1.0 keV with a peak cross section of 11.2 ± 0.2 b (1982SM02): see Table 7.4 (in PDF or PS) [Ex = 7459.7 ± 1.2 keV]. No other clearly defined resonance is observed to En = 49.6 MeV although the total cross section exhibits a broad maximum at En ≈ 4.5 MeV J.A. Harvey and N.W. Hill, private communication). The analyzing power has been measured for Epol. n = 1.48 to 4.38 MeV (1982DR06) and at 2 to 5 MeV (1975HO01, 1981CH12). An R-matrix analysis of the latter results as well as σt, σ(θ) and (n, α) results leads to a set of parameters for 7Li states. These include a bound 1/2+ and an unbound 3/2+ state (at 9.38 ± 0.03 MeV) [neither reported in other reactions] as well as the 5/2- state at 7.46 MeV [Γα = 33 ± 1 keV, reduced width 0.96 ± 0.01 MeV], a 3/2- state at 9.16 ± 0.14 MeV [Γα = 2.09 ± 0.18 MeV, γ2 = 0.13 ± 0.05 MeV] and a 1/2- state at 9.74 ± 0.05 MeV [no significant Γα, γ2 = 1.87 ± 0.18 MeV] (1981CH12). Another recent R-matrix analysis (1983KN1G) suggests an unbound 1/2+ state at 8.81 MeV, a 3/2+ state at 9.97 MeV and a 1/2- state at 10.31 MeV, in addition to the previously known states. The spectroscopic factors for the l = 0 decay to 6Lig.s. are S = 0.2 and 0.8 for 7Li*(8.81, 9.97). The states suggested by (1983KN1G) are very broad and cannot be seen directly in reaction or compound nucleus cross-section work (see also reaction 13). The two positive-parity states in 7Li are consistent with the 6Li + n scattering and reaction cross sections and provide an explanation for the anisotropy of the 6Li(n, t)α reaction at low energies (1983KN1G). See also (1982ST15; theor.).
The excitation function for 3.56 MeV γ-rays exhibits an anomaly, also seen in the (n, p) reaction (reaction 8). The data are well fitted assuming Eres = 3.50 and 4.60 MeV [Ex = 10.25 ± 0.10 and 11.19 ± 0.05 MeV], T = 1/2 and 3/2, Γc.m. = 1.40 ± 0.10 and 0.27 ± 0.05 MeV, respectively; both Jπ = 3/2-. The reduced widths for the T = 3/2 state [7Li*(11.19)] are θ2n = 2 × 10-4, θ2n'' = 0.16 [to 6Li*(3.56)] and θ2p = 0.09: see also (1979AJ01) for a discussion of these and other (unpublished) data.
For reaction (a) see (1976GO12). The excitation function, measured from threshold to En = 8.9 MeV, exhibits an anomaly at En = 4.6 MeV. The excitation function, at forward angles, of p0 is approximately constant for En = 4.4 to 7.25 MeV: see (1979AJ01). See also 6He, (1980MI02) and (1982SH1K; applied).
The isotopic thermal cross section is 940 ± 4 b: see (1981MUZQ). See also (1981EN01). Below 5 keV, the total cross section is given by σ = (149.5/(square root of E) (eV)) +0.696 b: see (1979AJ01). See also (1981IN1B). The 1/v dependence of the cross section (strong l = 0 waves) is not understood in terms of the known level structure of 7Li: see e.g. (1982SM02). In the 1 eV to 10 keV energy region, the ORNL results give an energy dependence for the asymmetry in the forward-to-backward 66° cone (lab) of the form A = 1+0.0055(square root of En), where En is the energy in eV (J.A. Harvey and I.G. Schroder, private communication). See, however, reaction 7.
A resonance occurs at En = 241 ± 3 keV with σmax = 3.15 ± 0.08 b (1978LA23; En = 3 to 800 keV), 3.36 ± 0.6 b (1978RE1B; En = 80 to 470 keV). The resonance is formed by p-waves, Jπ = 5/2-, and has a large neutron width and a small α-width: see Table 7.4 (in PDF or PS). Above the resonance the cross section decreases monotonically to En = 18.2 MeV (1983BA17), except for a small bump near En ≈ 1.8 MeV [see (1976GAYV, 1979AJ01)] and an inflection near En = 3.5 MeV, corresponding, presumably, to the anomaly reported in (n, n'γ) [see reaction 7] [7Li*(10.25), Jπ = 3/2-, T = 1/2] (1979BA37; En = 2.2 to 9.7 MeV). See also (1980BA39).
Angular distributions have been measured at many energies in the range En = 0.1 to 7.3 MeV [see (1979AJ01)], 2 and 24 keV (1979ST03), 2.0 to 3.5 MeV (1982KNZZ), 2.16 to 9.66 MeV (1980BA39) and at 14.1 MeV (1982HI06). See also (1977HA1J).
(1979BO1E) report a right-left asymmetry for polarized thermal neutrons of (0.95 ± 0.4) × 10-4. Polarization measurements are reported by (1977KA06) for Epol. n = 0.2 to 2.4 MeV: the data suggest interference between s-waves and the p-wave resonance at 0.25 MeV. Interference between this 5/2- state and a broad 3/2- state 2 MeV higher also appears to contribute. At the higher energies Ay is close to +0.9 near 90° and varies slowly with En (1977KA06). See also (1982KNZZ).
At Ep = 600 MeV, the reaction prefereantially excites 7Li*(4.63). Angular distributions have been obtained for the pions to 7Li*(0, 0.48, 4.63) at Ep = 600 MeV (1977BA37) and 800 MeV (1981NA1C). The T = 3/2 state 7Li*(11.24) is not observed (1977BA37). See also (1980KE1D, 1981WI1F, 1982LE1L, 1982NA1K, 1982LO1B) and (1979ME2A, 1980WH1A).
Angular distributions of proton groups have been studied for Ed = 0.12 to 15 MeV [see (1966LA04, 1974AJ01, 1979AJ01)] and at 698 MeV (1981BO03; p0 → p3). S = 0.90 and 1.15 for 7Li*(0, 0.48) [DWBA analysis]; Jπ of 7Li*(0.48) is 1/2-. The two higher states have Ex = 4.630 ± 0.009 and 7.464 ± 0.010 MeV, Γc.m. = 93 ± 8 and 91 ± 8 keV. 7Li*(7.46) appears to be a 24P state: see (1974AJ01). Reaction (b) at Ed = 10 MeV appears to proceed via 7Li*(7.46) and possibly 7Li*(9.6) [Γ = 0.5 ± 0.1 MeV]. Reaction (c) strongly involves 7Li*(4.63, 7.46) (Ed = 7.5 → 10.5 MeV): see (1979AJ01). See also (1979HO04). For the breakup involving 3He emission see (1979HO04). See also 8Be, (1981CE04) and (1979ME2A, 1980WH1A, 1982LO1B).
The total photoneutron cross section rises sharply from 10 MeV to reach a broad plateau at about 15 mb from 14 to 20 MeV, decreases more slowly to about 0.5 mb at 25 MeV and then decreases further to about 0.3 mb at Eγ = 30 MeV (monoenergetic photons): there are indications of weak structure throughout the entire region. Differential cross sections for n0 and n1 have been reported for Eγ = 7 to 25 MeV. The integrated cross section to 23 MeV is 39 ± 4 MeV · mb for the n0 transition and 17 ± 4 MeV · mb for the n1 transition: together these account for 0.4 of the exchange augmented dipole sum of 7Li: see (1979AJ01). The integrated cross section for formation of 6Li*(3.56) is 4 ± 1 MeV · mb to 30 MeV and 11 ± 3 MeV · mb to 55 MeV (1978DE13).
The total absorption cross section for natural Li in the range 10 to 340 MeV shows a broad peak at ≈ 30 MeV (σmax ≈ 3 mb), a minimum centered at ≈ 150 MeV at ≈ 0.3 mb and a fairly smooth increase in cross section to ≈ 3 mb at ≈ 320 MeV (1979AH1A, 1979ZI1A). See also the references in (1979AJ01).
The cross section for the (γ, p) reaction (reaction (c)) shows a maximum at ≈ 15.6 MeV with a width of ≈ 4 MeV: see (1974AJ01). It then decreases fairly smoothly to 27 MeV (1979JU02). The integrated cross section for 11 → 28 MeV is 13.2 ± 2.0 MeV · mb (1979JU02). For the earlier work see (1979AJ01). Differential cross sections for the (γ, n0 + n2) and (γ, p0) processes are reported by (1983SE07; Eγ = 60 to 120 MeV). Reaction (e) has been studied in the giant resonance reaction with Ebs ≲ 30 MeV. Deuteron groups to 5Heg.s. and possibly to the first excited state are reported. States of 7Li with Ex = 25 - 30 MeV may be involved when Ebs = 37 to 50 MeV is used: see (1979AJ01). See also (1979JU02, 1982KIZW).
The cross section for reaction (f) at 90° displays a broad resoannce at E ≈ 7.7 MeV (Γ = 7.2 MeV) with an integrated cross section of 6.2 MeV · mb, a plateau for 12 → 22 MeV (at ≈ 0.6 the cross section at 7.7 MeV) and a gradual decrease to 48 MeV. The (γ, t) cross section integrated from threshold to 50 MeV is 8.1 MeV · mb (1979SK05; monoenergetic photons; angular distributions). See also (1979JU02). For the earlier work on this reaction see (1966LA04, 1979AJ01). For reaction (g) see (1978VO03) and (1979AJ01). For pion production see (1979BO23, 1981BE13) and 7Be. See also (1980IS1E, 1981IS06), (1978CH1E, 1979MA1G, 1980AH1A) and (1978FI10, 1979KI1D, 1980BA34, 1980MO1M, 1980SU04, 1980TA1D, 1981DE18, 1981IS11, 1982DE12, 1983BU1F; theor.).
The electric form factor measurements for Ee = 100 to 600 MeV are well accounted for by a simple harmonic oscillator shell model with a quadrupole contribution described by an undeformed p-shell: Rrms = 2.39 ± 0.03 fm, |Q| = 42 ± 2.5 mb. From results obtained for Ee = 24.14 to 97.19 MeV, Rrms = 2.35 ± 0.10 fm (model independent), 2.29 ± 0.04 fm (shell model). A study of the ratio of the electric charge scattering from 6Li and from 7Li as a function of (momentum transfer)2 yields < r2 > 1/26/ < r2 > 1/27 = 1.001 ± 0.008. The rms radius of the ground-state magnetization density distribution, < r2 > 1/2M = 2.98 ± 0.05 fm. From the ratio of transverse inelastic and elastic cross sections at 180°, B(M1, ↑; 0.48) = 2.50 ± 0.12 μ2N. The cross section for the longitudinal excitation of 7Li*(0.48) has been found from the scattering through angles of 90° to 150°, B(C2, ↑; 0.48) = 7 ± 4 fm4: see (1979AJ01) for references. The form factor for 7Li*(0.48) has been measured at θ = 180° for 0.4 < q < 0.75 fm-1 (1982BU09): Γ0(M1) = (7.5 ± 1.7) × 10-3 eV, in good agreement with earlier values. Form factors for 7Li*(0, 0.48) are also reported for 0.8 < q < 2.9 fm -1 (1983LI07).
Inelastic scattering studies show peaks corresponding to 7Li*(4.63, 6.68, 7.46, 11.24) in addition to 7Li*(0.48): see (1974AJ01) and Table 7.5 (in PDF or PS). Quasi-elastic processes have been studied by (1978KU06; 250 → 580 MeV/c). At Ee = 700 MeV the proton separation spectra (reaction (b)) are similar to those observed in (p, 2p) (1978NA05). See also (1980AS02) and 6He, 6Li for reactions (b) and (c). At Ee = 450 to 1096 MeV (1980TI05) have studied the contributions of longitudinal and transverse components of the cross section for inelastic scattering: the effect of meson-exchange currents is observed.
Angular distributions have been measured at Eπ+ = 49.7 MeV (1978DY01; elastic), Eπ± = 143 MeV (1982GI01; to 7Li*(0, 0.48, 4.63, 6.68, 7.46, 9.67)) and 164.4 MeV (1979BO1F, 1979BO1G; to 7Li*(0, 0.48, 4.63, 6.68)). Total cross sections for π on Li (from which partial cross sections were then derived) have been obtained for π+ and π- at sevseral energies in the range 85 → 315 MeV (1981AS07, 1979NA04). See also (1982OS01; theor.) and the "GENERAL" section here.
Angular distributions have been measured at En = 1.5 to 14.6 MeV [see (1979AJ01)] and at En = 4.1 to 7.5 MeV (1979KN01; n0+1), 6.97 to 13.94 MeV (1979HO11; n0+1), 8.96 to 13.94 MeV (1979HO11; n2), 9.1 MeV (1977BI12; n0+1, n2) and 10 to 18 MeV (1981DA1K; n0). Reaction (b) at En = 14.4 MeV proceeds primarily via 7Li*(4.63) although some involvement of 7Li*(6.68) may also occur: see (1979AJ01). See also 8Li, (1979BA1R), (1980KA1R; applications) and (1982KO1U); theor.).
Angular distributions of protons have been measured for Ep = 49.8 to 155 MeV: see (1974AJ01) and at Ep = 24.4 MeV (1982PE06; p0, p1, p2). Inelastic proton groups have been observed corresponding to 7Li*(0.48, 4.63, 6.68, 7.46, 9.6 ± 0.2): see (1952AJ38, 1974AJ01).
For reaction (b) see (1980CH05; 800 MeV), 6He and (1979AJ01). For reaction (c) see (1981ER10; 670 MeV) and 5He. Reaction (d) proceeds sequentially via 7Li*(4.63, 6.68). At Ep = 100 MeV (1977RO02) find Sα = 0.94 ± 0.05, using a DWIA analysis, a value close to that predicted by simple LS-coupling shell-model predictions. See also (1978LA11, 1980KI1D, 1982GO1H) and (1979AJ01). For reaction (e) see (1979AJ01) and (1982ER06; 670 MeV). See also 8Be, (1982YA1A) and (1978BA1C, 1978WO1A, 1979KI10, 1980KO1V, 1981IS11, 1982BA1W; theor.).
Angular distributions are reported at E(3He) = 11 MeV (elastic) [see (1974AJ01)], at 44.04 MeV (1979GO07; g.s.) and at E(pol. 3He) = 33.3 MeV (1981BA37; 7Li*(0, 0.48, 4.63). See also 10B and (1979KA1G). At E(3He) = 37.5 MeV, the three-body final states which are most strongly populated are the 3He + α + t and 3He + d + 5He branches. Detection of 3He - t coincidences lead to a most probable momentum for the spectator α-particle of 60 MeV/c; the d - 3He breakup results suggest the unlikelihood of deuteron clusters in 7Li: see (1979AJ01).
Angular distributions (reaction (a)) have been reported for Eα = 3.6 to 29.4 MeV [see (1974AJ01)] and at 5 and 6 MeV (1982WA23). Reaction (b) has been studied at Eα = 18 to 64.3 MeV: see (1974AJ01) and (1980KI1D, 1980ZH1A). 7Li*(4.63) is strongly involved in the sequential decay. 7Li*(7.46) may also be involved. For pion production see (1981AB04). See also (1979ST25), (1979AJ01), (1978GU16, 1981BA20, 1981GU1B, 1982GU1E; theor.) and 11B in (1980AJ01, 1985AJ01).
The elastic angular distribution has been measured at E(7Li) = 34 MeV (1977KE09).
The elastic scattering (reaction (a)) has been studied at E(7Li) = 4.5 to 36 MeV [see (1975AJ01, 1979AJ01)] and at 48, 63.0, 78.7 MeV (1979ZE01, 1980ZE03; also 7Li*(0.48) [and 12C*(0, 4.4)]) and 89 MeV (1979BR04; and 12C*(0, 4.4)). For elastic scattering studies involving 13C see (1979AJ04, 1981AJ01). For fusion measurements and yield curves see (1982DE30, 1982TA23). See also (1981SH01) and (1979SU1F, 1981GU1B, 1982CO16; theor.).
The elastic scattering has been studied at E(7Li) = 28.8 MeV (1982WO09; reaction (a)), 68 and [reaction (c)] 89 MeV (1979BR03). See also (1979AJ01, 1979VA1B), (1980KH09, 1981GU1B; theor.) and 20Ne in (1983AJ01).
The elastic scattering has been studied at E(7Li) = 89 MeV (1980CO11, 1980ST06, 1981CO05, 1982CO16, 1982CO18), and at 27 MeV (1982WO09; reaction (b)). See also (1982HN1A, 1982TA23) and (1982CO05; theor.).
Angular distributions involving 7Li*(0, 0.48) and various states of 28Si and 40Ca have been studied at E(7Li) = 45 MeV (1982EC01). The elastic scattering (reactions (b) and (c)) has been studied at E(7Li) = 28 and 34 MeV (1977CU02), 88.7 MeV (1980ST06) and 89 MeV (1982NA14; also 7Li*(0.48)). See also (1982HN1A) and (1982CO18, 1983CO05; theor.).
The decay proceeds to the ground and 0.48 MeV states. The branching ratio to 7Li*(0.48) is 10.39 ± 0.06%: see Table 7.6 (in PDF or PS). A recent value of 15.4 ± 0.8% has been suggested by (1982ROZS). However subsequently a number of groups have remeasured the branching ratio and find agreement with an earlier value. [In (1979AJ01) the value of (1974GO26) was improperly quoted; it is (10.35 ± 0.08)%]. The adopted half-life is 53.29 ± 0.07 d. Both transitions are superallowed: log ft = 3.32 and 3.55 for the decays to 7Li*(0, 0.48). See (1978RA2A, 1979AJ01) for references.
The energy of the γ-ray is 477.605 ± 0.003 keV (1978HE21), 477.6064 ± 0.0026 keV (1983KU03) [Ex derived from the mean Eγ is 477.612 ± 0.002 keV]. See also (1978SA1B, 1981SA22), (1974AJ01, 1979HE19, 1980VA1D, 1981KH1E, 1982MC1D), (1975ZI1A, 1978BA1E, 1979DA1D, 1980PE1N, 1981BA1L, 1981BA2G, 1982BA80, 1982CO1D, 1983LI01, 1983TR1F; astrophysics) and (1979DE15; theor.).
The capture of stopped pions has been studied in a kinematically complete experiment: 7Li*(0, 0.48) are weakly populated. Two large peaks are attributed to the excitation of 7Li*(7.46, 10.25) [see, however, Table 7.2 (in PDF or PS)]. The recoil momentum distributions corresponding to these peaks are rather similar and both indicate a strong L = 0 component (1977BA51).
At Ep = 43.7 MeV angular distributions have been obtained for the 3He particles corresponding to 7Li*(0, 0.48, 4.63, 7.46). The 7.46 MeV state is strongly excited while the mirror state in 7Be is not appreciably populated in the mirror reaction (see reaction 15 in 7Be). The angular distribution indicates that the transition to 7Li*(7.46) involves both L = 0 and 2, with a somewhat dominant L = 0 character. The Jπ = 3/2-, T = 3/2 state is located at Ex = 11.28 ± 0.04 MeV, Γ = 260 ± 50 keV: see (1979AJ01) for references. See also (1981DE1X).
Angular distributions have been measured for Ed = 0.4 to 27.5 MeV: see (1966LA04, 1974AJ01, 1979AJ01). A study at 11 MeV finds Γc.m. = 93 ± 25 and 80 ± 20 keV, respectively, for 7Li*(4.63, 7.46). No evidence is found for the T = 3/2 state 7Li*(11.25). In a kinematically complete study of reaction (b) at Ed = 26.3 MeV, 7Li*(4.6, 6.5 + 7.5, 9.4) are strongly excited. No sharp α-decaying states of 7Li are observed with 10 < Ex < 25 MeV. Parameters for 7Li*(9.7) are Ex = 9.36 ± 0.05 MeV, Γ = 0.8 ± 0.2 MeV: see (1979AJ01). See also 8Be, 11B in (1980AJ01, 1985AJ01) and (1980DE42, 1980DE43, 1980NE11, 1982LA09).
Angular distributions to 7Li*(0, 0.48) have been studied at E(6Li) = 5.5 and 6.5 MeV: see (1979AJ01).
Angular distributions of α0, α1 and of α2 at the higher energies have been measured at En = 0.2 to 14.4 MeV [see (1979AJ01)] and at 2 and 24 keV (1979ST03; α0, α1). See also 11B in (1980AJ01), (1978LI32) and (1980MU1D; applied).
See (1982DO1E; Ed = 13.6 MeV).
See reaction 20 in 7Be.
Delayed α-particles have been observed in the β- decay of 11Be: they are due to the decay of 11B*(9.88) [Jπ = 3/2+]. This state decays by α-emission 87.4 ± 1.2% to the ground state of 7Li and 12.6 ± 1.2% to 7Li*(0.48) (1981AL03). See also 11Be, 11B in (1985AJ01).
At Ed = 13.6 and 19.5 MeV angular distributions have been measured for the transitions to 6Lig.s. and 7Li*(0, 0.48): see 6Li.
Angular distributions have been measured at Eα = 27.2 MeV (1983DO1F; see 8Be) and at Eα = 28.4 and 29.0 MeV (to 7Li*(0, 0.48) and 8Be*(0, 2.9)) and at 65 MeV (to 7Li*(0, 4.63)). At Eα = 65 and 72.5 MeV, 7Li*(0, 4.63) are very strongly populated while 7Li*(0.48, 6.68, 7.46) are weakly excited. See (1979AJ01) for references.
At Ed = 39.8 MeV, angular distributions have been measured for the transitions to 7Li(0) + 7Be(0), 7Li*(0.48) + 7Be(0), 7Li(0) + 7Be*(0.43), and 7Li*(0.48) + 7Be(0.43). Assymetries exceeding 20% are observed in the ratio of the cross sections to 7Li(0) and 7Be(0): see (1979AJ01).
At Eα = 65 MeV this reaction proceeds via 7Li*(4.63) (1978SA26).
Angular distributions have been obtained at E(6Li) = 36 MeV for the transitions to 7Li*(0, 0.48): see (1979AJ01).
An angular distribution involving 7Lig.s. + 7Beg.s. has been measured at Ep = 45.0 MeV: see (1974AJ01).
At E(6Li) = 34 MeV angular distributions have been measured for the transitions involving 7Lig.s. + 12Cg.s., 7Li*0.48 + 12Cg.s., 7Lig.s. + 12C*4.4, and 7Li*0.48 + 12C*4.4: see (1979AJ01).
At En = 14.1 MeV, 7Li*(0, 0.48) are approximately equally populated. At En = 18.2 MeV, 7Li*(4.63) may be involved: see (1979AJ01).
At Ed = 14.6 to 15.0 MeV, angular distributions have been measured for the transitions to 12C(0) + 7Li*(0, 0.48) [reaction (a)], 13C(0) + 7Li*(0, 0.48) [reaction (b)] and 14N(0) + 7Li*(0, 0.48) [reaction (c)]: see (1979AJ01). Angular distributions involving 7Li*(0, 0.48) are also reported at Ed = 13.6 MeV (reaction (b)) (1980GA1K).