# A new no-exchange R-matrix program

## Description

Abstract An R-matrix program is described implementing a new faster technique for calculating the elements of the Hamiltonian matrix when exchange and the quadratically integrable functions are omitted. It gives accurate results for high partial waves and can be used to supplement low partial wave results including exchange. Title of program: RMATRX NX Catalogue Id: ACGP_v1_0 Nature of problem Electron-atom and electron-ion Hamiltonian matrix eigenvalues and eigenvectors are calculated in LS coupling neglecting exchange. This gives accurate results for high partial waves which can be used to supplement low partial wave results including exchange. Versions of this program held in the CPC repository in Mendeley Data ACGP_v1_0; RMATRX NX; 10.1016/0010-4655(92)90131-H This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)