# Two-center Coulomb functions

## Description

Abstract Two-center Coulomb functions are crucial to describe the ionization continua of diatomic molecules, since the latter cannot be well represented by linear combinations of one-center Coulomb functions. A code to numerically evaluate the two-center angular as well as radial regular Coulomb functions is presented here. Title of program: TCOULOM Catalogue Id: ADFY_v1_0 Nature of problem Subroutine TCOULOM is a FORTRAN77 subroutine to calculate the regular two-center Coulomb functions for the positive energy, epsilon. This program requires six constants. R: internuclear distance, Z1 and Z2: two positive charges, m and q: quantum numbers, epsilon: energy of an outgoing electron. Atomic units are employed. Versions of this program held in the CPC repository in Mendeley Data ADFY_v1_0; TCOULOM; 10.1016/S0010-4655(97)00045-3 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)