
^{15}O (1991AJ01)(See Energy Level Diagrams for ^{15}O) GENERAL: See also (1986AJ01), 2 [Electromagnetic Transitions in A = 1315] (in PDF or PS), 15.16 [Table of Energy Levels] (in PDF or PS) and 15.17 [Radiative decays in ^{15}O] (in PDF or PS). Nuclear models:(1987ST05). Special states:(1985SH24, 1986LI1B, 1987ST05, 1988AN1E, 1989WU1C). Electromagnetic transitions:(1984VA06, 1987HO1L, 1987ST05). Astrophysical questions:(1985TA1A, 1987RA1D, 1989JI1A, 1989ST14, 1990RA1O). Complex reactions involving ^{15}O:(1985FI08, 1985HU1C, 1985PO11, 1985SI19, 1986GR1A, 1986ME06, 1986PO06, 1986TO10, 1986UT01, 1987BA38, 1987BE1I, 1987BU07, 1987NA01, 1987RI03, 1987ST01, 1988BE02, 1988BE56, 1988MI28, 1989BA92, 1989CA25, 1989DR03, 1989KI13, 1989PO07, 1989SA10, 1989TA1O, 1989YO02). Applied work:(1985BO1P, 1985HA40, 1987HI1B, 1988HI1F, 1988VO1D, 1989AR1J, 1989WO1B). Pion and other mesons capture and reactions (See also reactions 8, 16, 17 and 21.): (1986LI1B, 1987LE1B, 1988CH49, 1988MI1K, 1989LE1L, 1990OD1A). Hypernuclei:(1984ZH1B, 1986DA1G, 1989BA93, 1989KO1H, 1989TA17). Other topics:(1985AN28, 1985SH24, 1986AN07, 1986WI03, 1987CH02, 1989WU1C, 1990MU10). Groundstate properties of ^{15}O:(1985AN28, 1985AR11, 1986MC13, 1986WI03, 1986WUZX, 1987FU06, 1987SA15, 1988AR1B, 1988CH1T, 1988FU04, 1988NI05, 1988SH07, 1988VA03, 1988WA08, 1989CH24, 1989FU05, 1989NE02, 1989SA10).
^{15}O*(5.24): μ = +(0.65 ± 0.07) nm: see (1989RA17).
The halflife of ^{15}O is 122.24 ± 0.16 s: see (1981AJ01); log f_{0}t = 3.637. The K/β^{+} ratio is (10.7 ± 0.6) × 10^{4}: see (1976AJ04). The βanisotropy has been measured by (1988SE11, 1989DE07). See also (1986AJ01), (1990ST08), (1985BA1N, 1985BA1M, 1986GR04, 1987BA89, 1987FR1C, 1987RI1E, 1987WE1C, 1988BA86, 1988BA1Y, 1989BA2P, 1989DA1H; astrophysics) and (1988TA09, 1988TO1C, 1989WO1E; theor.).
For reaction (a) see (1986BE54); for reaction (b) see (1986BE35). For other heavyion reactions see (1986AJ01).
Excitation functions and polarization measurements for these reactions have been measured over a wide range of energies: see 15.20 in (1970AJ04 (in PDF or PS), 1976AJ04 (in PDF or PS), 1981AJ01 (in PDF or PS)) and the text below. Observed resonances are displayed in 15.18 (in PDF or PS) here.
The 90° yield and the angular distributions of γ_{0}, measured from E(^{3}He) = 5.24
to 13.95 MeV show five resonances attributed to E1 transitions from J^{π} = 1/2^{+} or 3/2^{+}, T = 1/2 states
in the GDR characterized by a considerable 3p4h admixture ((1978DE33) [also for
ω_{γ}], (1984DE09)). Yields of
γ_{1+2} at 90° have also been reported at
E(^{3}He) = 5.3 to 16.7 MeV: the cross section is some eight times
greater than that for (^{3}He, γ_{0})
and is similar to that for the The yield of n_{0} (reaction (b)) shows resonances for E(^{3}He) < 10 MeV and little structure above, to 30.6 MeV: see (1981AJ01) [n_{1} and n_{2+3+4} yields are also reported]. The yield of protons (reaction (c)) shows some clear resonances below E(^{3}He) = 4.5 MeV and some uncorrelated structures at higher energies (to E(^{3}He) = 12 MeV) with the possible exception of states at E_{res} = 7.8, 9.2  9.6 and (10.5) MeV. For E(^{3}He) = 16 to 30.6 MeV no appreciable structure is observed in the p_{0}, p_{1} and p_{2} yields: see (1976AJ04). At E(^{3}pol. He) = 33 MeV A_{y} has been measured for ^{14}N*(0, 2.31, 3.95): see (1986AJ01). For polarization effects in the (^{3}He, 2p) reaction at E(^{3}pol. He) = 33 MeV see (1986KA44). For reactions (d) and (e) see (1976AJ04, 1981AJ01, 1986AJ01). The elastic scattering (reaction (f)) shows some resonant structure near 3, 5 and 6 MeV and some largely uncorrelated structures in the range E(^{3}He) = 16.5 to 24 MeV. There is some suggestion, however, of two resonances at E(^{3}He) = 17 and 20 MeV: see (1976AJ04). Resonancelike behavior is also reported at E(^{3}pol. He) = 29 MeV. Polarization measurements are reported for E(^{3}pol. He) = 20.5 to 32.6 MeV: see (1981AJ01). See also (1986AJ01). The yield of αparticles displays resonance structure below 8 MeV, and broad fluctuations for E(^{3}He) = 12 to 18.6 MeV: see (1976AJ04). Polarization measurements are reported for E(^{3}pol. He) = 33.3 MeV for the α_{0} and α_{1} groups: see (1981AJ01). For A_{y} measurements of the (^{3}He, ^{7}Be) and (^{3}He, ^{6}Li) reactions see (1989SI02, 1986CL1B). For π^{±} production see (1986MI25). For a search for subthreshold K^{+} production see (1985IA01). For work at very high energies see (1985AB1B, 1985AD1C). See also (1986AJ01), (1984NA1F), (1990TO10; applied) and (1986EV01, 1986SI02; theor.).
Angular distributions of the n_{0} group have been measured for E_{α} = 18.4 to 23.1 MeV: see (1976AJ04). At E_{α} = 41 MeV angular distributions are reported to ^{15}O*(5.24, 6.86 + 7.28, 9.63[u], 10.48[u], 11.72[u], 12.85[u], 15.05[u]). ^{15}O*(8.92, 11.1, 12.3, 13.45, 13.72, 14.27, 15.65) are also populated ((1981OV01) [uncertainties in E_{x} are not shown; unresolved states are a problem]). At E_{α} = 47.4 MeV groups are populated at θ = 0° corresponding to ^{15}O_{g.s.} and to unresolved states at 5.2, 7.3, 10.0, 12.5 and 15.3 MeV (1988LU02). See also (1988CA26; astrophys.).
States observed in this reaction are displayed in 15.19 (in PDF or PS) (1975BI06: E(^{6}Li) = 59.8 MeV). Comparisons of angular distributions of the triton groups in this reaction and of the ^{3}He groups to analog states in ^{15}N have been made: analog correspondence is established for (10.48  10.70), (12.84  13.15 (u)) and (15.05  15.49 (u)) [E_{x} in ^{15}O, E_{x} in ^{15}N; u = unresolved] (1975BI06). See also (1976AJ04) for the earlier work.
At E(^{12}C) = 187 MeV, θ_{lab} = 8°, the spectrum is dominated by ^{15}O*(12.84, 15.05) [assumed J^{π} = 1/2^{}, 13/2^{+}, respectively]. ^{15}O*(7.28) [J^{π} = 7/2^{+}] is populated but ^{15}O*(0, 6.79) are not observed. The situation is similar at E(^{12}C) = 114 MeV but at E(^{12}C) = 72 MeV (θ_{lab} = 11°) ^{15}O*(0, 5.2, 7.28) are populated with comparable intensities: see (1976AJ04). At E(^{12}C) = 480 MeV the three most strongly excited states in the forward direction are ^{15}O*(10.46, 12.83[u], 15.05[u]) [J^{π} = 9/2^{+}, 11/2^{}, 13/2^{+}] and forward angle σ(θ) have been measured. ^{15}O*(0, 5.24, 7.3, 8.9[u], 16.7[u], 18.2[u], 21.1[u], 22.1[u]) are also populated (1988KR11).
Observed groups are displayed in 15.22 (in PDF or PS) of (1981AJ01).
At E_{pol. p} = 183 MeV differential cross sections and A_{y} are reported for the transitions to ^{15}O*(0, 7.3), the two states strongly populated in the reaction (1982JA05, 1982VI05). See also (1986JA1H) and (1986KU1J, 1990KU1H; theor.).
Observed resonances in the yield of γrays are listed in 15.20 (in PDF or PS). Branching ratios are displayed in 15.17 (in PDF or PS). Measurements of E_{γ} lead to E_{x} = 5183 ± 1, 5240.9 ± 0.4, 6175 ± 2, 6794 ± 2, 6858 ± 2, 8284.1 ± 0.8, 8922 ± 2 and 8978 ± 2 keV: see (1981AJ01)). For τ_{m} see (1981AJ01). (1987SC1H) have studied absolute cross sections, γray angular distributions and excitation functions for E_{p} = 0.2 to 3.6 MeV: S(0) is determined to be 3.20 ± 0.54 keV · b. C^{2}S are derived for the first eight states of ^{15}O (1987SC1H). The 90° γ_{0} yield has been measured for E_{p} = 2.2 to 19 MeV: resonances are observed over most of the range. The (γ_{1} + γ_{2}) yield is relatively weak. For E_{p} = 18 to 28 MeV the excitation function for γ_{0} decreases smoothly with energy: there is no evidence for structures [see (1981AJ01)]. See also (1985CA41, 1987KR04, 1987WE1C, 1988CA1J, 1988CA26, 1989BA2P, 1989TH1C, 1990MA1P; astrophysics) and (1990HA46; theor.).
The excitation function has been measured for E_{p} = 6.3 to 12 MeV: see (1970AJ04). Observed resonances are displayed in 15.20 (in PDF or PS). The cross section [obtained by measuring the 2.31 MeV γrays from the ^{14}O (β^{+}) decay] is reported at 12 energies in the range E_{p} = 7 to 22 MeV (1981DY03). Production cross sections for the 2.31 MeV γrays have been measured at E_{p} = 8.9, 20, 30, 33 and 40 MeV by (1988LE08). The ratio of the cross section to ^{14}O_{g.s.} to that for the analog state ^{14}N*(2.31) [from the (p, p') reaction] has been determined at E_{p} = 35 MeV (1984TA02). Forwardangle differential cross sections (n_{0}) are reported by (1979MO16) at E_{p} = 144 MeV. See also (1985CA41; astrophys.) and ^{14}O.
The yields of elastic and inelastic protons, and of 2.31 MeV γrays, have been studied at many energies: see (1959AJ76, 1970AJ04, 1976AJ04). Observed resonances are displayed in 15.20 (in PDF or PS). At higher energies excitation functions have been measured for the p_{0}, p_{1} and p_{2} groups for E_{p} = 17 to 26.5 MeV: there is no evidence for resonant behavior but the p_{1} yield shows a large increase between E_{p} = 20 and 23 MeV. Total cross sections for the p_{0} → p_{9} groups have been measured at E_{p} = 8.6, 10.6, 12.6 and 14.6 MeV [see (1981AJ01)]. Total reaction cross sections have also been measured in the range E_{p} = 22.9 to 49.0 MeV by (1985CA36). (1988LE08) report 2.31MeV γray production cross sections at E_{p} = 8.9, 20, 30, 33 and 40 MeV. For measurements at E(^{14}N) = 516 MeV/A see (1990WE14). Polarization measurements have been carried out at E_{p} = 3.0 to 159.4 MeV [see (1970AJ04, 1976AJ04, 1986AJ01)] and at E_{pol. p} = 35 MeV (1990IE01; p_{1}) and 0.8 GeV (1985BL22; A_{y}; elastic). See also ^{14}N, (1986BA2U), (1986BA88, 1987HU01) and (1989AM01; theor.).
Excitation functions for the groundstate group have been measured at E_{p} = 7 to 11 MeV: some resonant structure is indicated [see 15.20 (in PDF or PS)]. See also (1976AJ04).
Excitation functions and total crosssection measurements have been measured for the α_{0} group for E_{p} = 3.8 to 45 MeV: see (1976AJ04). Fairly sharp structures persist until E_{p} = 15 MeV: see 15.20 (in PDF or PS) here and footnote ^{e} in 15.23 (in PDF or PS) of (1981AJ01). See also (1986AI04; applied) and (1985CA41; astrophys.).
Angular distributions have been studied at many energies in the range E_{d} = 0.9 to 11.8 MeV: see 15.27 (in PDF or PS) and 15.28 (in PDF or PS) in (1970AJ04) and 15.26 (in PDF or PS) in (1976AJ04). For τ_{m} measurements see (1970AJ04). See also 15.21 (in PDF or PS) here, ^{16}O in (1986AJ04), (1987HI1B; applied) and (1984BL21; theor.).
See 15.28 (in PDF or PS) in (1970AJ04). See also 15.21 (in PDF or PS) here.
At E_{γ} = 170 MeV fourpoint angular distributions of the π^{} to ^{15}O_{g.s.} have been measured by (1988LI23) and (1989KO28): the two studies are not in good agreement. See also (1990ER03; theor.).
Angular distributions of the π^{0} to ^{15}O_{g.s.} have been studied at E_{π+} = 32.4 and 55.5 MeV (1985IR02), at 48 MeV (1984CO04, 1986LE01) and at 165 MeV (1982DO10). Forwardangle differential cross sections of the π^{0} to ^{15}O_{g.s.} have also been measured at E_{π+} = 20 MeV (1987IR01) and at 40.7 and 63.6 MeV (1985IR02). See also (1989LE1L).
Angular distributions have been measured for E_{p} = 3.95 to 18.5 MeV [see (1981AJ01, 1986AJ01)], at 35 MeV (1987OR01; ^{15}O*(7.56) [J^{π} = 1/2^{+}]), at 135 MeV (1985WA24; ^{15}O*(0, 6.2)) and at 200 and 494 MeV (1988CIZZ; prelim.; also A_{y}). Forwardangle differential cross sections at E_{p} = 200, 300 and 400 MeV to ^{15}O*(0, 6.2) are reported by (1987ALZW; prelim.). The ratio of the population of ^{15}O_{g.s.} to that of ^{15}O*(6.2) has been determined at E_{p} = 800 MeV (1986KI12). ^{15}O*(6.2) contains only about 1/3 of the expected GT strength (1985GO02). [I am indebted to Prof. C.D. Goodman for his comments.] For a discussion of GT strengths, see (1987TA13). ^{15}O*(5.2[u], 6.8[u], 7.28) have also been populated (1987OR01). For the earlier work see (1986AJ01). See also ^{16}O in (1986AJ04), (1985GO1Q, 1986VO1G, 1987BE25, 1988RO17, 1988WA1Q), (1986MA1P, 1987HI1B, 1988HI1F; applied) and (1989RA15; theor.).
Angular distributions for the t_{0}, t_{1+2}, t_{3}, t_{4+5}, t_{6} and t_{7} groups have been studied for E(^{3}He) = 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 J^{π} = 1/2^{} and 3/2^{} states E_{x} = 0 and 6.18 MeV, consistent with the basic validity of the singleparticle, singlehole theory of photoexcitation in ^{16}O. However, the positiveparity states at E_{x} = 5.18, 5.24, 6.86 MeV are also populated suggesting some more complicated excitations in ^{16}O: (1970AJ04, 1976AJ04). Differential cross sections for the n_{0} group have been measured from threshold to E_{γ} = 28 MeV [see (1976AJ04)], at E_{γ} = 60 to 160 MeV (also ^{15}O*(6.18); no appreciable strength in the 5.2 MeV doublet) [see (1986AJ01)] and at 150, 200 and 250 MeV (1989BE14). See also ^{16}O in (1986AJ04) and (1987RY03, 1988CA10, 1988DUZX, 1988RY03, 1990BRZY, 1990FL1A; theor.).
For reaction (a) see (1982DO01). At E_{π+} = 2.0 GeV/c differential cross sections have been determined for the transition to ^{15}N*(6.2) (1983KI01) in reaction (b). For reaction (c), see (1986GI1A).
At E_{p} = 505 MeV the summed spectra show two peaks corresponding to the p_{1/2} and p_{3/2} knockouts [^{15}O*(0, 6.18)] (binding energies of 15.64 and 21.82 MeV). Differential cross sections are also reported (1986MC10) [see also reaction 59 in ^{15}N]. For work at 1 GeV, see (1985BE30). See also (1983WA1C) and (1987HI1B; applied).
Angular distributions have been reported at many energies for E_{p} = 18.5 to 155.6 MeV [see 15.30 in (1970AJ04) (in PDF or PS), (1976AJ04), (1986AJ01)]: at those energies ^{15}O*(0, 6.18) are preferentially populated. At E_{p} = 200 MeV angular distributions have been studied for ^{15}O*(0, 6.18) (1989AB01) [also A_{y} and C^{2}S]. At E_{p} = 800 MeV ^{15}O*(0, 5.2[u], 6.18, 7.4[u], 9.0[u], 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 two states have Γ ≥ 0.8 MeV] have been populated (1984SM04). For γray production [^{15}O*(5.24)] see (1988LE08). See also ^{17}F in (1986AJ04), (1989WA16) and (1987LA11, 1988LE08, 1989GU28; astrophysics).
Angular distributions have been reported at a number of energies in the range E_{d} = 20 to 52 MeV [see (1981AJ01) and reaction 60 in ^{15}N here] and at E_{pol. d} = 89 MeV (1990SA27; ^{15}O*(0, 6.18)). See also ^{18}F in (1983AJ01).
The p_{1/2} and p_{3/2} hole states ^{15}O*(0, 6.18) are strongly populated. Information on these and other states are displayed in 15.25 (in PDF or PS) of (1981AJ01). Angular distributions have been measured at energies up to E(^{3}He) = 217 MeV: see (1981AJ01). Branching ratios and multipole mixing ratios are displayed in 15.17 (in PDF or PS). (1978BE73) report τ_{m} of ^{15}O*(5.24) = 3.25 ± 0.30 ps, g = 0.260 ± 0.028. (1983BI10) determine g = +0.17 ± 0.07. See also (1986AJ01), ^{19}Ne in (1983AJ01) and (1990AB14; applied).
See (1986GL1E; prelim.).
At E_{p} = 39.8 MeV angular distributions of t_{0} and t_{3} groups have been compared to those of the ^{3}He groups to the analog states in ^{15}N. At E_{p} = 45 MeV a state, assumed to be the J^{π} = 5/2^{+}, T = 3/2 analog of ^{15}C*(0.74), is observed at E_{x} = 12.255 ± 0.013 MeV, Γ_{c.m.} = 135 ± 15 keV. The state decays by proton emission to the T = 1, 0^{+} state ^{14}N*(2.31) [the population of some T = 1/2 states is also reported]: see (1981AJ01). E_{pol. p} = 89.7 MeV angular distributions and A_{y} measurements have been reported to ^{15}O*(0, 5.24[u], 6.18, 6.86, 7.28) (1985VO12).
See (1976AJ04). See also (1986HA1E; theor.).
