Lifetimes of Nuclear Isomers

Lifetimes of nuclear isomers for gamma-transitions are calculated theoretically on the basis of various independent particle models; e.g., single proton, single neutron, and states of several particles (Sec. II). The calculations of this paper are essentially restricted to the most common type of transition viz., multipole order equal to spin change. The lifetime is expressed in terms of a matrix element, $M$, whose theoretical value depends on the particular model of the nucleus. Radial integrals are calculated numerically, assuming that the nuclear wave functions are given by single particle wave functions for a spherical square well.