ROTATIONAL RELAXATION AND COLLISIONAL ENERGY-TRANSFER CALCULATIONS BASED ON A NEW FITTING LAW

The relaxation of some initially excited molecules (rigid rotators) interacting with a heat bath of other molecules is investigated. We propose a new fitting law for quantitative estimates of the rotationally inelastic rate constants, which is analytically derived from the energy corrected sudden (ECS) approximation. The quasiclassical ECS-E model is shown to give analytical expressions for energy transfer moments, Q-branch line widths and rotational relaxation time. As an example, all higher-order approximations for the rotational relaxation time are obtained in an explicit form. The validity of this model is tested for the case of energy relaxation in nitrogen.