Normal Coordinate Analysis and Vibrational Modes of Nitrosylchloride

Abstract

The infrared absorption spectrum of nitrosylchloride gas was first observed by Bailey and Cake1 who assigned the three fundamentals
at 1832(ν 1), 633(ν 2), and 923(ν 3) cm-1 but Beeson and Yost2 later showed that these fundamentals could not account for the observed entropy and reinterpreted the spectrum. Mini and Mazzariol3 determined centrifugal distortion constants from microwave studies and by using these data along with the vibrational frequencies they calculated the force constants for a general quadratic force field. Therefore, in order to obtain additional information of the molecule the Wilson’s FG matrix method has been followed to carry out the normal coordinate analysis of NOCl with a systematic set of symmetry coordinates. The molecule exhibits the Cs point group symmetry. Potential energy distribution has also been calculated for the normal modes of vibration to check whether the chosen
set of vibrational frequencies contribute maximum to the potential energy associated with the normal coordinates of the molecule.