Journal of Physical Chemistry A, Vol.104, No.45, 10565-10575, 2000
Quasi-resonant vibration-rotation transfer in inelastic Li-2*-Ne collisions
We present the results of a detailed study of the influence of rotational angular momentum on vibrotational transfer in the system Li-2*(v(i),j(i)) + Ne --> Li-2*(v(f),j(f)) + Ne, where v(i,f) and j(i,f) indicate initial and final vibrational and rotational levels, respectively, and Li-2* is in its first electronically excited (1)Sigma (+)(u) state. Level-to-level inelastic rate constants for j(i) up to 76 have been measured. The measurements span 4 orders of magnitude in size and include \Deltav\ less than or equal to 5 and \Deltaj\ less than or equal to 50 The results extend the range of previous measurements in this system and further document the phenomenon of quasiresonant vibrotational transfer. This process, induced by high rotational angular momentum, results in large rate constants for vibrational transfer and a systematic correlation of Deltaj and Deltav according to the rule Deltaj = -4 Deltav. At j(i) greater than or equal to 64, the total vibrationally inelastic rate constant is found to be larger than the total rotationally inelastic rate constant. A fully classical treatment of the dynamics on an ab initio potential surface results in rate constants that agree remarkably well with the data.