Shell Model Monte Carlo Studies of γ-Soft Nuclei

We present shell model Monte Carlo calculations for nuclei in the full major shell 50–82 for both protons and neutrons. For the interaction we use a pairing plus quadrupole derived from a surface-peaked separable force. The methods are illustrated for ${}^{124}$Sn, ${}^{128}$Te, and ${}^{124}$Xe. We calculate shape distributions, moments of inertia, and pairing correlations as functions of temperature and angular velocity. Our calculations are the first microscopic evidence of γ-softness of nuclei in this region.