(See Energy Level Diagrams for 15O)
The half-life of 15O is 122.24 ± 0.16 sec: see (1981AJ01); log f0t = 3.637. The K/β+ ratio is (10.7 ± 0.6) × 10-4: see (1976AJ04). See also (1982OS1C, 1983GO2C), (1981BA2G, 1982CO1D, 1983LI01, 1984BO1C, 1984DA1H, 1984HA1M, 1985KL1A; astrophys.), (1982KA1C; applied) and (1980AF1A, 1981ME1H, 1982OS1C; theor.).
Angular distributions have been measured at E(14N) = 73.9 and 100 MeV: see (1981AJ01).
Excitation functions and polarization measurements for these reactions have been measured over a wide range of energies: see Tables 15.20 in (1970AJ04 (in PDF or PS), 1976AJ04 (in PDF or PS)), (1981AJ01) and the text below. Observed resonances are displayed in Table 15.19 (in PDF or PS) here.
The 90° yield and angular distributions of γ0, measured from E(3He) = 5.24 to 13.95 MeV show five resonances attributed to E1 transitions from Jπ = 1/2+ or 3/2+, T = 1/2 states in the GDR characterized by a considerable 3p4h admixture (1978DE33 [also for ωγ], 1984DE09). See also (1983MAZZ, 1984MAZP). The yield of n0 (reaction (b)) shows resonances for E(3He) < 10 MeV and little structure above, to 30.6 MeV: see (1981AJ01) [n1 and n2+3+4 yields are also reported]. See also (1984SH04; Xn).
The yield of protons (reaction (d)) shows some clear resonances below E(3He) = 4.5 MeV and some uncorrelated structures at higher energies (to E(3He) = 12 MeV) with the possible exception of states at Eres = 7.8, 9.2 - 9.6 and (10.5) MeV. For E(3He) = 16 to 30.6 MeV no appreciable structure is observed in the p0, p1 and p2 yields: see (1976AJ04). At E(3He) = 33 MeV Ay is measured for 14N*(0, 2.31, 3.95) (1983LE17, 1983RO22). For reaction (d) see (1981AJ01) and (1983DR06; E(pol. 3He) = 33 MeV; g.s.; also dp). See also (1984AB1G; Xd). For reaction (e) see (1976AJ04).
The elastic scattering (reaction (f)) shows some resonant structure near 3, 5 and 6 MeV and some largely uncorrelated structures in the range E(3He) = 16.5 to 24 MeV. There is some suggestion, however, of two resonances at E(3He) = 17 and 20 MeV: see (1976AJ04). Resonance-like behavior is also reported for E(pol. 3He) = 29 MeV. Polarization measurments are also reported for E(pol. 3He) = 20.5 to 32.6 MeV: see (1981AJ01). Recently the elastic yield has been measured for E(3He) = 1.0 to 2.7 MeV (1980VO1C). See also (1981AS04; n 3He cross section at 910 MeV). The yield of α-particles displays resonance structure below 8 MeV, and broad fluctuations for E(3He) = 12 to 18.6 MeV: see (1976AJ04). Polarization measurements are reported for E(pol. 3He) = 33.3 MeV for the α0 and α1 groups: see (1981AJ01). For total cross sections see (1980DE28, 1981PE01). For a fragmentation study at 10.78 GeV/c see (1985AB1H). See also (1983CA07, 1984AA01), (1980TR02, 1981RO1H, 1985BL1B) and (1981LE01, 1984NA06; theor.).
Angular distributions of the n0 group have been measured for Eα = 18.4 to 23.1 MeV: see (1976AJ04). At Eα = 41 MeV angular distributions are reported to 15O*(5.24, 6.89 + 7.26, 9.63, 10.48, 11.71, 12.85, 15.05). 15O*(0, 8.91, 11.1, 12.3, 13.45, 13.72, 14.27, 15.65) are also populated (1981OV01 [uncertainties in Ex are not shown; unresolved states are a problem]). See also (1981HAZV, 1983KOZD, 1984GO03) and 16O in (1986AJ04).
States observed in this reaction are displayed in Table 15.20 (in PDF or PS) (1975BI06: E(6Li) = 59.8 MeV). Comparisons of angular distributions of the triton groups in this reaction and of the 3He groups to analog states in 15N have been made: analog correspondence is established for (10.48 - 10.70), (12.84 - 13.15(u)) and (15.05 - 15.49(u)) [Ex in 15O, Ex in 15N; u = unresolved] (1975BI06). See also (1976AJ04) for the earlier work, 18F in (1987AJ02) and (1980KR1F).
At E(12C) = 187 MeV, θlab = 8° the spectrum is dominated by 15O*(12.84, 15.05) [assumed Jπ = 1/2-, 13/2+, respectively]. 15O*(7.28) [Jπ = 7/2+] is populated but 15O*(0, 6.79) are not observed. The situation is similar at E(12C) = 114 MeV but at E(12C) = 72 MeV (θlab = 11°) 15O*(0, 5.2, 7.28) are populated with comparable intensities: see (1976AJ04).
At Epol. p = 183 MeV differenatial cross sections and Ay are reported for the transitions to 15O*(0, 7.3), the two states strongly excited in the reaction (1982JA05, 1982VI05). See also (1982GR1K, 1984JA1F), (1984BEZZ; theor.) and the "GENERAL" section here.
The cross section increases from (8.5 ± 3.7) × 10-12 b at 100 keV to (140 ± 30) × 10-12 b at 135 keV. Extrapolation from the Ep = 0.28 MeV resonance gives S(0) = 2.75 ± 0.50 keV · b, with zero slope to Ep = 0.05 MeV. Measurements of Eγ lead to Ex = 5183 ± 1, 5240.9 ± 0.4, 6175 ± 2, 6794 ± 2, 6858 ± 2, 8284.1 ± 0.8, 8922 ± 2 and 8978 ± 2 keV.
The 90° yield γ0 curve has been measured for Ep = 2.2 to 19.0 MeV: resonances are observed over most of the range in the γ0 yield. The (γ1 + γ2) yield is relatively weak. For Ep = 18 to 28 MeV the excitation function for γ0 decreases smoothly with energy: there is no evidence for structures. τm = 8.2 ± 1.0, > 3000, < 2.5, 16.0 ± 2.5 and 750 ± 200 fsec for 15O*(5.18, 5.24, 6.18, 6.86, 7.28), respectively. For references and additional discussions see (1976AJ04, 1981AJ01). See also (1982KR05, BL84E), (1980WE1D, 1982WE01) and (1980BA2M, 1982BA80, 1984BO1Q, 1984MA67, 1984TR1C; astrophys.).
The excitation function has been measured for Ep = 6.3 to 12 MeV: see (1970AJ04). Observed resonances are displayed in Table 15.21 (in PDF or PS). The cross section [obtained by measuring the 2.31 MeV γ-rays from the 14O(β+) decay] is reported at 12 energies in the range Ep = 7 to 22 MeV (1981DY03). The ratio of the cross section to 14Og.s. to that for the analog state 14N*(2.31) [from the (p, p') reaction] has been determined at Ep = 35 MeV (1984TA02). See also 14O.
The yields of elastic and inelastic protons, and of 2.31 MeV γ-rays, have been studied at many energies: see (1959AJ76, 1970AJ04, 1976AJ04). Observed resonances are displayed in Table 15.21 (in PDF or PS). At higher energies excitation functions have been measured for the p0, p1 and p2 groups for Ep = 17 to 26.5 MeV: there is no evidence for resonant behavior but the p1 yield shows a large increase between Ep = 20 and 23 MeV. Total cross sections for the p0 → p9 groups have been measured at Ep = 8.6, 10.6, 12.6 and 14.6 MeV. See (1981AJ01) and 14N.
Polarization measurements have been reported for Ep = 3.0 to 155 MeV: see Table 15.25 (in PDF or PS) in (1970AJ04), and (1976AJ04). Ay measurements have also been reported at Epol. p = 21 MeV (1982AO05; to 14N*(0, 2.31, 3.95) and 13N*(0, 3.51)) and at 159.4 MeV (1983TA12; p0, p1, p2). See also (1980LE28), (1981DY03, 1984RE14) and (1984AN1M; theor.).
Excitation functions and total cross-section measurements have been carried out for the α0 group for Ep = 3.8 to 45 MeV: see (1976AJ04). Fairly sharp structures persist until Ep = 15 MeV: see Table 15.21 (in PDF or PS) here and footnote e in Table 15.23 (in PDF or PS) of (1981AJ01).
Angular distributions have been studied at many energies in the range Ed = 0.9 to 11.8 MeV: see Table 15.27 (in PDF or PS) in (1970AJ04), and (1976AJ04). τm = 3.2 ± 0.5 psec, < 28 fsec, 0.70 ± 0.15 psec, respectively for 15O*(5.24, 6.79, 7.28): see (1970AJ04). Ky'y(0°) have been measured for Epol. d ≈ 7.5 to ≈ 14 MeV for the pol. n to an unresolved group involving at least 15O*(6.79, 7.55) (1981LI23). See also Table 15.22 (in PDF or PS), (1983MU13; theor.) and 16O in (1986AJ04).
Differential cross sections are reported for 15O*(0, 6.86, 7.28) at E(11B) = 115 MeV and for 15Og.s. at E(13C) = 105 MeV (1980PR09).
Angular distributions to 15Og.s. have been studied at Eπ+ = 48 MeV (1984CO04) and 165 MeV (1982DO10). At 48 MeV a deep forward-angle minimum is observed. It appears to reflect the analogous minimum in the free-nucleon cross section which is caused by cancellation between the s- and p-wave π-nucleon amplitudes (1984CO04).
Angular distributions have been measured for the n0 group at Ep = 3.95 to 18.5 MeV [and for the n2 group at Ep = 5.5 MeV]: see (1981AJ01) for the earlier work, (1981MU01: Ep = 5.5 to 9.3 MeV) and (1981BY01; 9.1 to 15.6 MeV). At Ep = 160 MeV transitions are observed to 15O*(0, 6.2, (9.6)): the transition to 15O*(6.2) [3/2-] is significantly more quenched than the 1/2 → 1/2 transition, as is also the case in 13C(p, n) (1985GO02). At Ep = 135 MeV 15O*(10.5) is weakly populated (1985PAZV). See also (1981BY1B, 1981WA1F, 1984TAZS, 1985KI1L), and (1983BY03) in 16O (1986AJ04).
Angular distributions for the t0, t1+2, t3, t4+5, t6 and t7 groups have been studied for E(3He) = 16.5 to 44.6 MeV: see (1976AJ04).
The spectrum of photoneutrons has been investigated at many energies. Measurements over the giant dipole resonance region show the predominant strength is to the Jπ = 1/2- and 3/2- states Ex = 0 and 6.18 MeV, consistent with the basic validity of the single-particle, single-hole theory of photoexcitation in 16O. However, the positive-parity states at Ex = 5.18, 5.24, 6.86 MeV are also populated suggesting some more complicated excitations in 16O: see (1970AJ04, 1976AJ04). Differential cross sections for the n0 group have been measured from threshold to Eγ = 28 MeV [see (1976AJ04)] and at Eγ = 60 to 160 MeV (1980GO13, 1982GO09, 1982SC02 [also 15O*(6.18); no appreciable strength in the 5.2 MeV doublet]). In the energy range Eγ = 30 - 35 MeV, ≈ 4% of the isovector energy-weighted sum rule is found in the (γ, n0) channel (1984KU21). See also (1981AJ01), 16O in (1986AJ04) and (1981GA1M, 1982LO1B).
Angular distributions have been reported at many energies for Ep = 18.5 to 155.6 MeV [see Table 15.30 (in PDF or PS) in (1970AJ04), and (1976AJ04)] and at Epol. p = 65 MeV (1980HO18; d0). At those energies 15O*(0, 6.18) are primarily populated. At Ep = 800 MeV (1984SM04) report the population of 15O*(0, 5.18 + 5.24, 6.18, 7.28 + 7.56, 8.84 + 0.15, 10.42 ± 0.15, 10.87 ± 0.15, 12.21 ± 0.15, 13.59 ± 0.15, 19.0 ± 0.2, 21.1 ± 0.2) [the last states have Γ ≥ 0.8 MeV]. See also (1981LI1B), (1982LO1B) and 17F in (1986AJ04).
The p1/2 and p3/2 hole states 15O*(0, 6.18) are strongly populated. Information on these and other states are displayed in Table 15.25 (in PDF or PS) of (1981AJ01). Angular distributions have been measured at energies up to E(3He) = 217 MeV: see (1981AJ01). Branching ratios and multipole mixing ratios are displayed in Table 15.18 (in PDF or PS). (1978BE73) report τm of 15O*(5.24) = 3.25 ± 0.30 psec, |g| = 0.260 ± 0.028. (1983BI10) determine g = +0.17 ± 0.07. For reaction (b) see (1984ST10; E(3He) = 81 MeV) and 16O. See also 19Ne in (1983AJ01), (1982AB04), (1983GO2D; applied) and (1982LO1B).
At Ep = 39.8 MeV angular distributions of t0 and t3 groups have been compared to those of the 3He groups to the analog states in 15N. At Ep = 45 MeV a state, assumed to be the Jπ = 5/2+, T = 3/2 analog of 15C*(0.74), is observed at Ex = 12.255 ± 0.013 MeV, Γc.m. = 135 ± 15 keV. The state decays by proton emission to the T = 1, 0+ state 14N*(2.31) [the population of some T = 1/2 states is also reported]: see (1981AJ01). See also (1984VOZY).