# A vibrational configuration interaction program for energies and resonance widths

## Description

Abstract We present a computer program to calculate energies and Feshbach golden-rule resonance widths of systems described by a two-dimensional vibrational Hamiltonian. The steps involved are evaluation of matrix elements over the potential and basis functions, diagonalization of a vibrational configuration interaction matrix, projection of the resonance component out of a new basis set (involving vibronic-interaction-like integrals), and evaluation of the transition matrix elements. Title of program: VIBCI Catalogue Id: ABDY_v1_0 Nature of problem The purpose of this program is to calculate energies and widths of vibrational resonances in two-dimensional systems. As detailed previously, we use stabilization to find an approximate resonance function and resonance energy, a Feshbach projection operator formalism to find a representative "continuum" function, and a golden-rule formalism to calculate the width. Versions of this program held in the CPC repository in Mendeley Data ABDY_v1_0; VIBCI; 10.1016/0010-4655(88)90075-6 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)