Investigation of intermolecular potential vibrational dependence

The influence of vibrational excitation of absorbing molecule on the intermolecular potential parameters is considered. It is proved that the vibrational dependence of intermolecular potential must be taken into account when the line shift of molecular absorption lines are calculated. The modem technique of the summation of perturbation theory divergent series am used for intermolecular potential series. First non-diagonal Pade approximant is obtained for intermolecular potential expansion over intermolecular distance for the collision of two helium atoms.