São Paulo potential version 2 (SPP2) and Brazilian nuclear potential (BNP)

Abstract

The REGINA code calculates the São Paulo potential version 2 (SPP2) and the Brazilian nuclear potential (BNP). The code also provides nuclear densities obtained from the Dirac-Hartree-Bogoliubov model, which are used to calculate the nuclear potentials. Elastic scattering cross sections are obtained within the context of the optical model, with different options for the real and imaginary parts of the optical potential. In this manuscript, we provide a summary of the theoretical framework and information about the use of the code. Program summaryProgram Title: REGINA.fCPC Library link to program files:https://doi.org/10.17632/vfkkjb8dv7.1Licensing provisions: GPLv3Programming language: Fortran-77Nature of problem: We provide a code to calculate the nuclear potential between two nuclei according to two different models: the São Paulo potential version 2 (SPP2), that includes a dependence on the relative velocity between the nuclei, and the velocity independent Brazilian nuclear potential (BNP). These potentials assume the effective nuclear interactions proposed in [1,2], and are obtained within the double-folding approach with nuclear densities calculated through the Dirac-Hartree-Bogoliubov model [3].Solution method: The code involves two files containing previously calculated results for theoretical neutron and proton distributions and also experimental charge densities obtained from electron scattering experiments. These results are used to obtain matter densities through convolution using Fourier transforms. The Fourier transform method is also employed to obtain the double-folding potentials. Integration of the Schrödinger equation with a complex optical potential is performed using the Cowell method [4,5]. With this, for a given system and energy, we obtain the S-matrix and the elastic scattering cross sections.Additional comments including restrictions and unusual features: The maximum angular momentum supported in the optical model calculations is 2000.