Shell-model calculations on negative-parity levels in A = 35, 37 and 39 nuclei

Abstract

Shell-model calculations of negative-parity states in 35Cl, 35S, 37Cl, 39Ar and 39K have been performed by assuming an inert 32S core with the residual interaction taking place within 1 d n 3 2 1 f 7 2 and 1d n case3 2 2 p 3 2 configurations (with n = 2, 4 or 6). For the effective two-body interaction the modified surface delta interaction (MSDI) has been used. The MSDI interaction parameters as well as the single-particle binding energies have been deduced from a least-squares fit to experimentally known levels in A = 35, 37 and 39 nuclei. Excitation energies. M1 and E2 transition strengths, gamma-ray branching ratios, magnetic dipole moments, spectroscopic factors and log ft values for allowed β-decay have been calculated. Where comparison with experimental values is possible, the agreement is reasonable. The calculated strengths of the strong analogue to anti-analogue M1 transitions are in excellent agreement with recent experimental results for 35Cl and 37Cl, whereas a discrepancy exists for 39K.