Eur. Phys. J. Plus (2016) 131: 226
https://doi.org/10.1140/epjp/i2016-16226-0

Regular Article

Shell-model study of ³¹S at excitations relevant to the thermonuclear ³⁰P(p,)³¹S reaction rate

¹ Laboratoire de Physique Appliquée et Théorique, Université Larbi Tébessi, 12022, Tébessa, Algeria
² IPHC, CNRS/IN2P3, Université de Strasbourg, F-67037, Strasbourg, Cedex2, France

^* e-mail: m_bouhelal@yahoo.fr

Received: 29 May 2015
Revised: 2 June 2016
Accepted: 10 June 2016
Published online: 5 July 2016

Abstract

Recent experimental data about the ³⁰P(p,) reaction have been reported, where a list of confirmed ³¹S excited states within 500 keV of the ³⁰P(p,)³¹S threshold at keV and their properties were studied. Definitive constraints on are only given for two levels; the other ones are either tentative (five states) or undefined (six states). In order to confirm the proposed spin/parity assignments and to determine the unknown ones a comparison with shell-model calculations is crucial. We have performed a shell-model calculation using the PSDPF interaction to calculate the excitation energy spectrum of mass 31 ( ³¹S - ³¹P up to 7000 keV. Between 6100 and 6700 keV, an excitation energy region of astrophysical interest, we obtain a set of negative-parity states that are good candidates for the observed ones. A complete spectrum of positive- and negative-parity states can now be proposed based also on a comparison with the ³¹P spectrum up to 7000 keV.