Ab initio investigation of the vibronic structure of the C<inf>2</inf>H spectrum II. Calculation of diabatic potential surfaces for the three lowest-lying electronic states in C<inf>2</inf>H

Abstract

Potential surfaces for the three lowest-lying electronic states of C2H (12A’, 22A’ and 12A’) calculated by means of the ab initio MRD-CI method are transformed into their adiabatic counterparts. Three simple approaches for determination of diabatic transformation are investigated. Diabatic potentials and electronic transition moments obtained as functions of the C-C bond length and the bond angle represent a suitable basis for the calculation of vibronic energy levels and probabilities for transitions between them. © 1990 Taylor & Francis Group, LLC.