# The evaluation of transition matrix elements for atomic excitations by a screened Coulomb potential

## Description

Abstract We have developed a FORTRAN code for calculating screened potential matrix elements for transitions between atomic bound states. In the applied procedure, the target wave functions can be arbitrarily chosen, and a wide class of screening potentials can be applied. The program includes subroutines for the calculation of the modified Bessel functions of fractional order and their derivatives for a broad range of argument and order. Title of program: SCRMTRX Catalogue Id: ADRB_v1_0 Nature of problem The electronic screening effect plays an important role in ion-atom collisions. Atomic or molecular transitions are often induced by the screened Coulomb potentials of atoms or partially ionized ions. The corresponding screening matrix elements are often required in theoretical descriptions. The SCRMTRX program calculates such screening matrix elements for bound-bound transitions for arbitrarily chosen target wave functions. Versions of this program held in the CPC repository in Mendeley Data ADRB_v1_0; SCRMTRX; 10.1016/S0010-4655(02)00696-3 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)