Spectroscopy ofF16from theO16(p,n)F16reaction at 99 and 135 MeV

Abstract

We measured neutron energy spectra and extracted angular distributions for eleven separate transitions for the /sup 16/O(p,n)/sup 16/F reaction at 99.1 and 135.2 MeV. Several new spin and parity assignments are obtained for states in /sup 16/F by comparison of the excitation energy spectra with known analog states in /sup 16/O and with a shell-model prediction and by analysis of the neutron angular distributions. The most strongly-excited are two 2/sup -/ states at E/sub x/ = 0.40 +- 0.05 and 7.6 +- 0.1 MeV, a 4/sup -/ states at 6.37 +- 0.05 MeV, and two broad 1/sup -/ states at 9.4 +- 0.1 and 11.5 +- 0.1 MeV. These states are analogs of known 2/sup -/ (M2) states, a 4/sup -/ ''stretched'' state, and 1/sup -/ (E1) strength, respectively, in /sup 16/O. Three weakly-excited 1/sup +/ states are observed at E/sub x/ = 3.75 +- 0.05, 4.65 +- 0.05, and 6.23 +- 0.05 MeV. These states are analogs of known 1/sup +/ (M1) states in /sup 16/O and directly indicate correlations in the ground state of /sup 16/O. A weakly excited 4/sup -/ state is seen at 5.93 +- 0.05 MeV in good agreement with a 4/sup -/ state observedmore » in /sup 16/O (e,e') measurements. All of the most strongly excited states align (to within +- 200 keV) with known T = 1 analog states in /sup 16/O for a common net displacement energy of 12.6 MeV. The (p,n) reaction at medium energies is shown to be an important spectroscopic tool.« less