Influence of Rotational - Vibrational Coupling on Shape of Rovibrational Bands

The integrated absorption coefficient ofrovibrational bands is calculated for three different cases, namely for separated rotational and vibrational motions, for the non-rigid model which takes into account the coupling between above mentioned motions using the Kratzer-Fues potential and the soft body model, for which only rovibrational states exist. It is shown that the shape of P and R bands for higher rotational quantum numbers depends on the applied model of rotational - vibrational transitions.