New development of the projected shell model and description of low-lying collective states in transitional nuclei

¹ Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
² Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, People’s Republic of China

^a e-mail: fangqi0591@qq.com
^b e-mail: sunyang@sjtu.edu.cn

Published online: 19 December 2013

Abstract

Description of the interplay between different nuclear shapes is an interesting but challenging problem. The original projected shell model (PSM) is applicable to nuclei with fixed shapes. We extend the PSM by superimposing (angular-momentum- and particle-number-) projected product wave functions in the spirit of the generate coordinate method. With this development, the Gd isotopes across the N = 90 region are studied, and the results indicate spectroscopic features of shape phase transition with varying neutron number. In order to illustrate the shape distribution in microscopic wave functions, we introduce a deformation representation and show that the collectively excited K^π = 0⁺ states in the Gd isotopes have characters of shape vibration.