(See Energy Level Diagrams for 17F)
Q = 0.10 ± 0.02 b (1974MI21).
The half-life of 17F is 64.49 ± 0.16 sec; log ft= 3.358 ± 0.002. The log ftvalue for the transition to 17O*(0.87) is > 5.6: see (1982AJ01, 1986AJ04). The β anisotropy has been measured with on-line isotope separation and low-temperature nuclear orientation (1988SE11, 1988VAZP, 1989SE07). See also (1988TA1N).
Gamow-Teller matrix elements were calculated for the 17F β+ decay in the relativistic scalar-vector shell model by (1990NE12). The effect of exchange currents arising from quark degrees of freedom was studied by (1988TA09). A relativistic analysis of semileptonic weak interactions is described in (1987KI22). See also (1987BA89, 1988BA1Y, 1988BA55, 1991NA05).
Excitation functions for γ0+1, γ2 and γ3 have been studied for E(3He) ≈ 3 - 18 MeV. Resonances are reported corresponding to 17F states at 20.1 ± 0.2 (γ2) [Γ = 1.07 ± 0.16 MeV], 20.4 ± 0.1 (γ1) [Γ = 0.7 ± 0.1] and 21.3 ± 0.1 MeV (γ1) [Γ = 0.9 ± 0.1] (1983WA05): see 17.19 (in PDF or PS) in (1982AJ01).
This reaction is important in astrophysical processes. Analytic expressions for reaction rates are given in (1988CA26). The rates are calculated on the basis of T = 1 analog structure in 18O and 18Ne by (1987WI11). See also the studies of this reaction in the framework of the generator coordinate method by (1988FU02, 1989FU01).
Angular distributions for reaction (a) involving 17F*(8.43, 10.7, 11.9, 13.51, 14.84) have been measured at E(6Li) = 36 MeV. For comparisons with the results in the analog reaction 14N(6Li, 3He)17O see (1986AJ04). For the earlier work see (1982AJ01).
Angular distributions have been reported to most of the states of 17F with Ex < 8.1 MeV at E(3He) = 3.8 and 4.8 MeV. Neutron groups have also been reported to 17F states at Ex = 11.195 ± 0.007, 12.540 ± 0.010 and 13.059 MeV, with Γ < 20, < 25 and < 25 keV, respectively. Angular distributions at E(3He) = 10.36 and 11.88 MeV lead to Jπ = 1/2- for 17F*(11.20) [L = 0], 3/2- or 5/2- for 17F*(12.54) and 3/2-, 5/2- for 17F*(13.06). These three states are probably the first three T = 3/2 states in 17F (1969AD02). The branching ratios for transitions to 16O*(0, 6.05, 6.13) for 17F*(11.20) and for the analog T = 3/2 state in 17O are displayed in 17.16 (in PDF or PS): the ratios of the reduced widths are quite different in the two mirror nuclei. See (1977AJ02) for the references.
At low energies the direct capture to 17F*(0, 0.50) is observed. Extrapolation of cross-section data leads to S(0) ≈ 8 keV · b: see (1977AJ02). In addition to two T = 1/2 resonances, five resonances corresponding to T = 3/2 states are observed in the γ1 and γ0 + γ1 yields: see 17.24 (in PDF or PS) for the reported parameters. The lowest T = 3/2 states of even parity at Ex = 13.27 and 14.02 MeV [Jπ = (1/2+) and 5/2+] (see 17.24 (in PDF or PS)) are not observed here: Γγ ≤ 7 and ≤ 11.8 eV, respectively (1975HA06).
The (γ0 + γ1) yield at 90° has been studied for Ep = 15.75 to 31.66 MeV: it shows the giant dipole resonance centered at Ex = 22 MeV with a width of ≈ 5 MeV and a pigmy resonance centered at 17.5 MeV. The integrated strength of the mainly T = 1/2 giant resonance is 10 MeV · mb; the observed strength distribution is in good agreement with odd parity 2p-1h, 1p shell excitation calculations. The pigmy resonance is due to f7/2 → d5/2. The main f7/2 strength lies in two states at Ex = 16.9 and 18.0 MeV (1975HA07). The γ0 yield at 60° for Ep = 20 to 100 MeV and differential cross sections at Ep = 20.8, 28.35, 49.2 and 49.69 MeV have been measured (1988HA04). Differential cross sections have been measured for 17O excitation energies Ex = 20 - 40 MeV by (1986ANZL, 1988CO10), and it is reported that the (p, γ0) data indicate a direct capture term and the excitation of giant dipole resonances based on excited states having a probable 2p-1h structure. See also (1986PO1D, 1987PO09, 1988PO1G). The 16O + p bremsstrahlung cross sections have been measured at Ep = 2.74 MeV at 155° by (1988PE12). For discussions of the 16O(p, γ)17F reaction in astrophysical processes see the reviews of (1985CA41, 1987RO25, 1988CA26), and see (1991RA1C).
Yield curves for elastic protons, protons scattered to 16O*(6.05, 6.13, 6.92, 7.12, 8.87) and for γ-rays from 16O*(6.13, 6.92) have been studied at many energies up to Ep = 46 MeV: see (1971AJ02, 1977AJ02, 1982AJ01). The observed resonances are displayed in 17.25 (in PDF or PS). Absolute σ(θ) [θ = 110° to 160°] have been measured for Ep = 0.60 to 2.00 MeV to ± 5% (1983BR11). Cross sections for bremsstrahlung emission are reported in the vicinity of the Ep = 2.66 MeV resonance by (1983TRZZ, 1988PE12, 1992DA19). A measurement of the lifetime of the state at Ex = 3.105 MeV in 17F is reported in (1990GOZN). The cross sections of the 6.13 MeV γ-ray at Ep = 23.7 and 44.6 MeV have been measured by (1981NA14), and (1979SC07) report the σt for Ep = 190 to 558 MeV. See also (1982AJ01).
Ay measurements have been made for inelastic scattering to many excited states of 16O for Ep = 35 - 200 MeV. Ay and spin transfer observables for p0, p2, p3, and p4 groups have been measured at Ep = 35 - 200 MeV and polarization transfer-coefficients have been studied at Ep = 200 MeV to 4- states of 16O. The spin rotation parameter Q has been measured for the elastic scattering at Ep = 65 MeV and 200 MeV. [See references in (1986AJ04).] In more recent work, differential cross sections and analyzing powers have been measured at Ep = 6.4 - 7.7 MeV (1992WI13), at Ep = 13.5 MeV for all narrow states below Ex = 12.1 MeV up to a momentum transfer of 3.2 fm-1 (1989KE03), at Ep = 35 MeV (1990OH04), and at Ep = 318 MeV for states with Ex < 14 MeV (1991KE02), and at Ep = 400 MeV for excitation of the Ex = 10.957 MeV 0-, T = 0 state (1991KI08). See also (1987KE1A, 1988SEZU). Quasielastic spin observables for elastic scattering are reported for Ep = 320, 400, 500, 650, and 800 MeV. Cross sections and analyzing powers for 0+ → 0- excitations in 16O with Ep = 200 MeV are reported in (1989SAZZ). See also (1986GA31, 1987PI02). Cross section measurements for gamma ray production relevant to astrophysics are discussed in (1987LA11, 1988LE08). See also (1988SA1B). For earlier work see (1982AJ01, 1986AJ04), and see the compilation of cross sections in (1986BA88), and the reviews of (1985KI1A, 1988ZA06). See also the conference reports (1986VDZY, 1986YE1B, 1987RO1F, 1989PLZU).
In recent theoretical work, a resonating group method study of 16O + p is discussed in (1990HA38), the alpha particle model is used to calculate elastic scattering observables in (1988BE57, 1992LI1D), and a Skyrme force approach to intermediate energy proton scattering is presented in (1988CH08). A Dirac coupled-channels analysis for (p, p') at Ep = 800 MeV is described in (1988DE35). See also (1988DE31, 1991PH01). Off-shell effects from meson exchange in the nuclear optical potential are studied in (1989EL02). See also the non-relativistic full-folding model descriptions of (1990AR03, 1990AR11, 1990CR02, 1990EL01, 1991AR1K). Dirac optical potentials are obtained in (1988HA08, 1990PH02). A comparison of Dirac and Schrodinger descriptions is made in (1990CO19). A relativistic microscopic optical potential is derived from the relativistic Brueckner-Bethe-Goldstone equation in (1992CH1E). Relativistic effects on quasielastic spin observables are discussed in (1988HO1K). Non relativistic multiple scattering theory is used for elastic scattering at Ep = 800 MeV in (1987LU04). See also (1992BE03). Effective interactions for elastic scattering above 300 MeV are discussed in (1990RA12). A second-order relativistic impulse approximation model is used for Ep = 500 and 800 MeV in (1988LU03). See also (1988OT04). An empirical effective interaction for excitation of 16O by 135 MeV protons is discussed in (1989KE05). The excitation of the 7.12 dipole state in 16O is shown to be non-collective (1988AM03). Effects of vacuum polarization and Pauli blocking are treated in (1988OT05). A review of relativistic theory of nuclear matter is presented in (1988MA1X). Spin-independent isoscalar response functions and interpretation of polarization-transfer measurements are discussed in (1986OR03). Recoil effects in the coordinate space Dirac equation have been studied (1987OT02). Effects of short range correlations on the self energy in the optical model are studied by (1992BO04). See also the calculation of (1992OL02) concerning resonance shapes and the A = 17 Theoretical discussion at the beginning of this compilation.
The analyzing power for the transition to the 4- state 16F*(6.37) has been measured at Ep = 135 MeV (1982MA11). See also (1983WA29). More recently, polarization observables have been measured at Ep = 135 MeV by (1989WAZZ). See also 16F.
The excitation function for d0 at θ = 70° has been measured for Ep = 21 to 38.5 MeV. A strong resonance is observed at Ep = 24 MeV: see 17.25 (in PDF or PS). The analyzing power has been measured for the d0 group at Ep = 65 MeV (1980HO18). Cross sections and analyzing powers have been measured at Ep = 200 MeV for the 1/2- (ground state) and 3/2- (6.18 MeV) levels in 15O. See also (1989WA16) and see (1982AJ01) for the earlier work.
Observed resonances are displayed in 17.25 (in PDF or PS). Some broad structures have been reported above Ep ≈ 15 MeV; particularly strong peaks appear at Ep ≈ 22 and 25.5 MeV: see (1977AJ02). Total cross sections were measured by the activation method up to Ep = 30 MeV by (1989WA16).
This reaction is involved in explosive burning in stars. Numerical values of thermonuclear reaction rates are tabulated in (1985CA41). See (1977AJ02, 1982AJ01) for the earlier work and see (1979MO04).
Parameters of the first excited state of 17F are Ex = 495.33 ± 0.10 keV, τm = 407 ± 9 psec: see (1971AJ02). See also 17.21 (in PDF or PS) in (1971AJ02). For polarization measurements see (1981LI23) and 18F in (1983AJ01). See also (1986AJ04, 1989VI1E). This reaction has been used in analysis of Oxygen in Flouride glasses (1990BA1M).
At E(3He) = 18 MeV, angular distributions of the deuterons to 17F*(0, 0.50, 3.104 ± 0.003, 3.857 ± 0.004) have been measured. The spectroscopic factors for 17F*(0, 0.50) are 0.94 and 0.83. Two-step processes appear to be involved in the excitation of 17F*(3.10, 3.86). Angular distributions have also been measured at E(3He) = 30 MeV (to 17F*(5.1, 5.7)) and at E(3He) = 33 MeV (d0, d1): see (1982AJ01) for references.
Angular distributions for 6He leading to the 17F 5/2+ ground state were measured at Elab = 34 MeV (1988KE07). The data are structureless and are neither described by finite range DWBA nor by coupled-channels Born approximation calculations.
At Ep = 135.2 MeV differential cross sections are reported for the transitions to 17F*(0, 0.5 ± 0.05, 4.84 ± 0.1, 5.89 ± 0.2, 6.34 ± 0.2, 7.26 ± 0.2, 7.64 ± 0.2, 9.3 ± 0.1, 14.3 ± 0.1). [Note known density of states.] The group to 17F*(4.84) has Γ = 1.8 ± 0.05 MeV (1985PU1A). For a discussion of Gamow-Teller transition probabilities see (1985WA24). For Ay measurements see (1983PUZZ, 1985PU1A). For the earlier work see (1982AJ01).
Angular distributions have been studied at E(3He) = 17.3 MeV [t0, t1]. Angular distributions and analyzing powers were measured at E(3He) = 33 MeV [t0]: see (1982AJ01).
A Jπ = 3+ level in 18Ne at Ex = 4.561 ± 0.009 MeV is reported in (1991GA03), and the effects of this result on the 17F(p, γ) thermonuclear reaction rate as well as astrophysical consequences are discussed.
Thermonuclear reaction rates for this reaction and other astrophysically important thermonuclear reactions are tabulated in (1985CA41). Analytic expressions for the reaction rates are given in (1988CA26). See also the study of processes and effects in (1989GU28), and see (1977AJ02) for earlier work.