
^{17}F (1993TI07)(See Energy Level Diagrams for ^{17}F) GENERAL: See 2 [Electromagnetic Transitions in A = 1617] (in PDF or PS), 17.22 [General Table] (in PDF or PS) and 17.23 [Table of Energy Levels] (in PDF or PS).
Q = 0.10 ± 0.02 b (1974MI21).
The halflife of ^{17}F is 64.49 ± 0.16 sec; log ft= 3.358 ± 0.002. The log ftvalue for the transition to ^{17}O*(0.87) is > 5.6: see (1982AJ01, 1986AJ04). The β anisotropy has been measured with online isotope separation and lowtemperature nuclear orientation (1988SE11, 1988VAZP, 1989SE07). See also (1988TA1N). GamowTeller matrix elements were calculated for the ^{17}F β^{+} decay in the relativistic scalarvector 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).
See (1982AJ01).
Excitation functions for γ_{0+1}, γ_{2} and γ_{3} have been studied for E(^{3}He) ≈ 3  18 MeV. Resonances are reported corresponding to ^{17}F states at 20.1 ± 0.2 (γ_{2}) [Γ = 1.07 ± 0.16 MeV], 20.4 ± 0.1 (γ_{1}) [Γ = 0.7 ± 0.1] and 21.3 ± 0.1 MeV (γ_{1}) [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 ^{18}O and ^{18}Ne 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 ^{17}F*(8.43, 10.7, 11.9, 13.51, 14.84) have been measured at E(^{6}Li) = 36 MeV. For comparisons with the results in the analog reaction ^{14}N(^{6}Li, ^{3}He)^{17}O see (1986AJ04). For the earlier work see (1982AJ01).
Angular distributions have been reported to most of the states of ^{17}F with E_{x} < 8.1 MeV at E(^{3}He) = 3.8 and 4.8 MeV. Neutron groups have also been reported to ^{17}F states at E_{x} = 11.195 ± 0.007, 12.540 ± 0.010 and 13.059 MeV, with Γ < 20, < 25 and < 25 keV, respectively. Angular distributions at E(^{3}He) = 10.36 and 11.88 MeV lead to J^{π} = 1/2^{} for ^{17}F*(11.20) [L = 0], 3/2^{} or 5/2^{} for ^{17}F*(12.54) and 3/2^{}, 5/2^{} for ^{17}F*(13.06). These three states are probably the first three T = 3/2 states in ^{17}F (1969AD02). The branching ratios for transitions to ^{16}O*(0, 6.05, 6.13) for ^{17}F*(11.20) and for the analog T = 3/2 state in ^{17}O 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 ^{17}F*(0, 0.50) is observed. Extrapolation of crosssection 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 γ_{1} and γ_{0} + γ_{1} yields: see 17.24 (in PDF or PS) for the reported parameters. The lowest T = 3/2 states of even parity at E_{x} = 13.27 and 14.02 MeV [J^{π} = (1/2^{+}) and 5/2^{+}] (see 17.24 (in PDF or PS)) are not observed here: Γ_{γ} ≤ 7 and ≤ 11.8 eV, respectively (1975HA06). The (γ_{0} + γ_{1}) yield at 90° has been studied for E_{p} = 15.75 to 31.66 MeV: it shows the giant dipole resonance centered at E_{x} = 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 2p1h, 1p shell excitation calculations. The pigmy resonance is due to f_{7/2} → d_{5/2}. The main f_{7/2} strength lies in two states at E_{x} = 16.9 and 18.0 MeV (1975HA07). The γ_{0} yield at 60° for E_{p} = 20 to 100 MeV and differential cross sections at E_{p} = 20.8, 28.35, 49.2 and 49.69 MeV have been measured (1988HA04). Differential cross sections have been measured for ^{17}O excitation energies E_{x} = 20  40 MeV by (1986ANZL, 1988CO10), and it is reported that the (p, γ_{0}) data indicate a direct capture term and the excitation of giant dipole resonances based on excited states having a probable 2p1h structure. See also (1986PO1D, 1987PO09, 1988PO1G). The ^{16}O + p bremsstrahlung cross sections have been measured at E_{p} = 2.74 MeV at 155° by (1988PE12). For discussions of the ^{16}O(p, γ)^{17}F reaction in astrophysical processes see the reviews of (1985CA41, 1987RO25, 1988CA26), and see (1991RA1C).
Yield curves for elastic protons, protons scattered to ^{16}O*(6.05, 6.13, 6.92, 7.12, 8.87) and for γrays from ^{16}O*(6.13, 6.92) have been studied at many energies up to E_{p} = 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 E_{p} = 0.60 to 2.00 MeV to ± 5% (1983BR11). Cross sections for bremsstrahlung emission are reported in the vicinity of the E_{p} = 2.66 MeV resonance by (1983TRZZ, 1988PE12, 1992DA19). A measurement of the lifetime of the state at E_{x} = 3.105 MeV in ^{17}F is reported in (1990GOZN). The cross sections of the 6.13 MeV γray at E_{p} = 23.7 and 44.6 MeV have been measured by (1981NA14), and (1979SC07) report the σ_{t} for E_{p} = 190 to 558 MeV. See also (1982AJ01). A_{y} measurements have been made for inelastic scattering to many excited states of ^{16}O for E_{p} = 35  200 MeV. A_{y} and spin transfer observables for p_{0}, p_{2}, p_{3}, and p_{4} groups have been measured at E_{p} = 35  200 MeV and polarization transfercoefficients have been studied at E_{p} = 200 MeV to 4^{} states of ^{16}O. The spin rotation parameter Q has been measured for the elastic scattering at E_{p} = 65 MeV and 200 MeV. [See references in (1986AJ04).] In more recent work, differential cross sections and analyzing powers have been measured at E_{p} = 6.4  7.7 MeV (1992WI13), at E_{p} = 13.5 MeV for all narrow states below E_{x} = 12.1 MeV up to a momentum transfer of 3.2 fm^{1} (1989KE03), at E_{p} = 35 MeV (1990OH04), and at E_{p} = 318 MeV for states with E_{x} < 14 MeV (1991KE02), and at E_{p} = 400 MeV for excitation of the E_{x} = 10.957 MeV 0^{}, T = 0 state (1991KI08). See also (1987KE1A, 1988SEZU). Quasielastic spin observables for elastic scattering are reported for E_{p} = 320, 400, 500, 650, and 800 MeV. Cross sections and analyzing powers for 0^{+} → 0^{} excitations in ^{16}O with E_{p} = 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). For reaction (b) see (1982REZZ, 1985BO1A, 1986CH1J, 1986KU15, 1986SA24, 1991CO13). For reaction (c) and for fragmentation see (1986AJ04) and see ^{16}O. In recent theoretical work, a resonating group method study of ^{16}O + 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 coupledchannels analysis for (p, p') at E_{p} = 800 MeV is described in (1988DE35). See also (1988DE31, 1991PH01). Offshell effects from meson exchange in the nuclear optical potential are studied in (1989EL02). See also the nonrelativistic fullfolding 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 BruecknerBetheGoldstone equation in (1992CH1E). Relativistic effects on quasielastic spin observables are discussed in (1988HO1K). Non relativistic multiple scattering theory is used for elastic scattering at E_{p} = 800 MeV in (1987LU04). See also (1992BE03). Effective interactions for elastic scattering above 300 MeV are discussed in (1990RA12). A secondorder relativistic impulse approximation model is used for E_{p} = 500 and 800 MeV in (1988LU03). See also (1988OT04). An empirical effective interaction for excitation of ^{16}O by 135 MeV protons is discussed in (1989KE05). The excitation of the 7.12 dipole state in ^{16}O is shown to be noncollective (1988AM03). Effects of vacuum polarization and Pauli blocking are treated in (1988OT05). A review of relativistic theory of nuclear matter is presented in (1988MA1X). Spinindependent isoscalar response functions and interpretation of polarizationtransfer 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 ^{16}F*(6.37) has been measured at E_{p} = 135 MeV (1982MA11). See also (1983WA29). More recently, polarization observables have been measured at E_{p} = 135 MeV by (1989WAZZ). See also ^{16}F.
The excitation function for d_{0} at θ = 70° has been measured for E_{p} = 21 to 38.5 MeV. A strong resonance is observed at E_{p} = 24 MeV: see 17.25 (in PDF or PS). The analyzing power has been measured for the d_{0} group at E_{p} = 65 MeV (1980HO18). Cross sections and analyzing powers have been measured at E_{p} = 200 MeV for the 1/2^{} (ground state) and 3/2^{} (6.18 MeV) levels in ^{15}O. See also (1989WA16) and see (1982AJ01) for the earlier work.
See (1982AJ01) and ^{14}N, ^{14}O in (1986AJ01).
Observed resonances are displayed in 17.25 (in PDF or PS). Some broad structures have been reported above E_{p} ≈ 15 MeV; particularly strong peaks appear at E_{p} ≈ 22 and 25.5 MeV: see (1977AJ02). Total cross sections were measured by the activation method up to E_{p} = 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 ^{17}F are E_{x} = 495.33 ± 0.10 keV, τ_{m} = 407 ± 9 psec: see (1971AJ02). See also 17.21 (in PDF or PS) in (1971AJ02). For polarization measurements see (1981LI23) and ^{18}F in (1983AJ01). See also (1986AJ04, 1989VI1E). This reaction has been used in analysis of Oxygen in Flouride glasses (1990BA1M).
At E(^{3}He) = 18 MeV, angular distributions of the deuterons to ^{17}F*(0, 0.50, 3.104 ± 0.003, 3.857 ± 0.004) have been measured. The spectroscopic factors for ^{17}F*(0, 0.50) are 0.94 and 0.83. Twostep processes appear to be involved in the excitation of ^{17}F*(3.10, 3.86). Angular distributions have also been measured at E(^{3}He) = 30 MeV (to ^{17}F*(5.1, 5.7)) and at E(^{3}He) = 33 MeV (d_{0}, d_{1}): see (1982AJ01) for references.
Angular distributions for ^{6}He leading to the ^{17}F 5/2^{+} ground state were measured at E_{lab} = 34 MeV (1988KE07). The data are structureless and are neither described by finite range DWBA nor by coupledchannels Born approximation calculations.
See (1982AJ01, 1986AJ04). Measurements of σ(θ) vs. Qvalue for reaction (f) were made at E_{lab} = 72 MeV by (1988AU03). Results were not compatible with a lowlfusion window.
At E_{p} = 135.2 MeV differential cross sections are reported for the transitions to ^{17}F*(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 ^{17}F*(4.84) has Γ = 1.8 ± 0.05 MeV (1985PU1A). For a discussion of GamowTeller transition probabilities see (1985WA24). For A_{y} measurements see (1983PUZZ, 1985PU1A). For the earlier work see (1982AJ01).
Angular distributions have been studied at E(^{3}He) = 17.3 MeV [t_{0}, t_{1}]. Angular distributions and analyzing powers were measured at E(^{3}He) = 33 MeV [t_{0}]: see (1982AJ01).
A J^{π} = 3^{+} level in ^{18}Ne at E_{x} = 4.561 ± 0.009 MeV is reported in (1991GA03), and the effects of this result on the ^{17}F(p, γ) thermonuclear reaction rate as well as astrophysical consequences are discussed.
See ^{17}Ne and 17.27 (in PDF or PS).
See (1983DE1A).
See (1977AJ02).
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.
See (1985FI08).
