Evolution of shapes and search for shape coexistence in Sd-shell nuclei

A detailed and systematic study has been performed using state dependent Relativistic Mean-Field plus BCS (RMF+BCS) approach to investigate shape evolution for even-even isotopes of Ne, Mg, Si and S. We perform quadrupole constraint calculation using NL3* parameter and look into the variation of binding energy with respect to deformation and find the shape and deformation corresponding to energy minima. We find various isotopes showing shape coexistence and shape transition while moving from proton drip-line to neutron drip-line. These results are compared with Macroscopic-microscopic approach (Mac-Mic) with Nilson Strutinsky (NS) prescription and some other works and are found consistent for these sd-shell nuclei. (author)