MICROSCOPIC NUCLEAR-LEVEL DENSITIES FROM FE TO GE BY THE SHELL-MODEL MONTE-CARLO METHOD

We calculate microscopically total and parity-projected level densitie s for beta-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 sin gle-particle level density parameter a and backshift parameter Delta a re extracted by fitting the calculated densities to a backshifted Beth e formula, and their systematics are studied across the region. Shell effects are observed in Delta 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 less than or similar to 60, which diminishes as A increases. (C) 199 8 Elsevier Science B.V. All rights reserved.