Sergy Yu. Grebenshcikov
Molecular dynamics at dissociation threshold is discussed, with ozone O3 as an example. The molecule is shown to support quantum mechanical bound states O...O2 localized far in dissociation channels and weakly coupled to the 'normal' bound states in the deep potential well of O2. The properties of these localized modes and their lifetimes are discussed from the point of view of quantum and classical mechanics and the quantum-classical correspondence. Further, vibrational cooling of highly excited O3 in collisions with argon atoms is analyzed. The direct vibrational energy transfer from ozone to argon is shown to be extremely inefficient. The cooling is achieved through another new indirect mechanism which involves irreversible intramolecular energy exchange between vibrational and rotational degrees of freedom of ozone. The properties of the intramolecular energy flow are studied using classical mechanics. The existence of the irreversible intramolecular energy exchange in quantum mechanics is discussed.