Nuclear mass parameters and moments of inertia in a folded-Yukawa mean-field approach

Abstract Collective moments of inertia as well as quadrupole and octupole mass parameters are calculated in the perturbative cranking approximation using the folded-Yukawa mean-field potential written in Cartesian coordinates. The resulting single-particle Hamiltonian is required, as a minimal symmetry, to be invariant under z-signature and time-reversal transformations. The deformation of the nucleus is defined through a shape parametrization in cylindrical coordinates, with the so-called Funny–Hills and Trentalange–Koonin–Sierk shapes as typical and performant examples. To take pairing correlations into account, the standard set of BCS equations is solved with an approximation of constant pairing strength. The numerical program determining the quadrupole–octupole mass tensor and the moments of inertia, written in Fortran, is constructed according to the here presented study as an extension and application of the “yukawa” code for the diagonalization of the folded-Yukawa mean-field potential in the basis of a harmonic-oscillator in Cartesian coordinates, published in this journal in 2016. Program summary Program Title: yukmoms Program Files doi: http://dx.doi.org/10.17632/9ygk4bgkfr.1 Licensing provisions: GPLv3 Programming language: Fortran Nature of problem: The moments of inertia and the quadrupole and octupole mass parameters are calculated within the perturbative cranking approximation. As an input, the folded-Yukawa mean-field is diagonalized in the harmonic-oscillator deformed basis to generate the single-particle energies and wave functions. Nuclear shapes are given by means of well known Funny–Hills or Trentalange–Koonin–Sierk parametrizations able to describe the elongation, mass asymmetry, non-axiality and neck of the deformed nucleus. Solution method: Having diagonalized the matrix corresponding to the folded-Yukawa single-nucleon Hamiltonian expressed in the basis of the anisotropic harmonic oscillator basis, one then calculates the matrix elements of the one-body angular-momentum as well as the quadrupole and octupole-moments operators. These matrix elements together with the solutions of the coupled BCS equations are essential input to calculate the desired collective masses and moments of inertia of atomic nuclei.