Knowledge Bank

Rotational state-to-state rate constants have been calculated for $O3-M$ collisions $(M=O3,N2,O2)$ by a semi-classical method based on multipolar and atom-atom potentials. Calculations lead to a strong Propensity for first-order quadrupolar transitions when the perturber is diatomic and to a propensity for both first-order quardrupolar-and dipolar-type for self relaxation. The $(100)\leftrightarrow (001)$ Coriolis-assisted intermode transfer, observed when pumping $O3$ molecules in a (100) rotational state and monitoring the ensuring population increase in a (001) rotational state, is too fast to be a pure near-resonant vibrational-vibrational energy transfer but results mainly from successive rotational energy transfers within the (100,001) dyad. We have then developed a kinetic model describing, by means of the calculated state-to-state rates, the rotational energy transfer within a large set of (100,001) rotational states. Such a kinetic model simulates as well pure rotational energy transfer as rovibrational transfers. It was applied to the available experimental data.