On the 9/2₁^-level excitation energy of odd Tl, Au and Ir isotopes

Abstract

A semi-empirical method inspired by Blomqvist's (1969) previous calculations of the excitation energy of the lowest 9/2- state of 201Tl is applied to similar calculations in different Tl, Au and Ir isotopes. These semi-empirical estimates agree well with the experimental values of the excitation energies as well as with the energy differences deduced from the analysis of the total potential energy surfaces calculated microscopically with Nilsson's model. The same excitation energies are computed with a spherical HF-BCS model which does not reproduce the available experimental data so well. An interpretation of these deviations is attempted.