The Renner effect in four‐atomic molecules

Abstract

The theory of the Renner effect in X2Y2 and X2YZ linear molecules is considered. The Renner equations are obtained with the help of the Born‐Oppenheimer method. It is shown that these equations contain two Renner parameters for an X2Y2 molecule and three Renner parameters for an X2YZ molecules. Assuming these parameters to be small enough, an approximate solution of the Renner equations is obtained with the help of perturbation theory. Some general qualitative results are obtained in the first order of the perturbation theory; the second order calculations are made for some specific cases. The theoretical results are used to consider experimental data concerning the vibrational structure of the 1IIu ‐ 1Σ g+ electronic transition in C2H2 and C2D2 molecules. The frequencies of the bending vibrations and the Renner parameters are calculated for the electronic 1IIu‐state mentioned. Copyright © 1972 John Wiley & Sons, Inc.