Parity dependence of nuclear level densities

A simple formula for the ratio of the number of odd- and even-parity states as a function of temperature is derived. This formula is used to calculate the ratio of level densities of opposite parities as a function of excitat ion energy. We test the formula with quantum Monte Carlo shell model calcul ations in the (Pf + g(9/2)) shell. The formula describes well the transitio n from low excitation energies where a single parity dominates to high exci tations where the two densities are equal.