Microscopic nuclear level densities from Fe to Ge by the shell model Monte Carlo method
Abstract We calculate microscopically total and parity-projected level densities for β -stable even-even nuclei between Fe and Ge, using the shell model Monte Carlo methods in the complete ( pf +0 g 9/2 )-shell. A single-particle level density parameter a and backshift parameter Δ are extracted by fitting the calculated densities to a backshifted Bethe formula, and their systematics are studied across the region. Shell effects are observed in Δ for nuclei with Z =28 or N =28 and in the behavior of A / a as a function of the number of neutrons. We find a significant parity dependence of the level densities for nuclei with A ≲60, which diminishes as A increases.