An abinitio study of the A2A′—X2A″ vibronic transition in the free radical HNF

Abstract

Potential energy curves for the two lowest electronic states X2A″ and A2A′(2Π in linear geometry) of HNF are calculated employing configuration interaction. A vibrational analysis of the A2A′—X2A″ transition is undertaken; stretching and bending modes are treated separately but vibronic coupling and large-angle bending is taken into consideration explicitly. The various vibronic levels including their K-type structure are compared with measured data wherever available and the results indicate that the prediction of vibronic spectra in small molecules on the basis of purely abinitio data is now within reach.