Topological study of nonadiabatic effects in Π electronic states of tetra-atomic molecules

Abstract

In this study, we investigate the topological structure of the adiabatic potential energy surfaces and nonadiabatic matrix elements in the framework of a simple model for handling the Renner–Teller effect in tetra-atomic molecules. The reliability of the transformation from the adiabatic to diabatic electronic basis functions is discussed. As a concrete example, we consider the X 2Πu electronic state of C2H2+.