Journal of Chemical Physics, Vol.104, No.4, 1415-1426, 1996
Dependence of Level-Resolved Energy-Transfer on Initial Vibrational Level in Li(2)A(1)Sigma(+)(U)-Ne Collisions
We have investigated collision induced rotational and vibrational energy transfer in the Li(2)A(1) Sigma(u)(+)(v(i), j(i)=30) -Ne system experimentally under single-collision conditions at an effective temperature of 691 K. Over 800 inelastic rate constants have been measured, with the initial vibrational level v(i) ranging from 2 to 24 and -2 less than or equal to Delta v+2. Increasing v(i) results in a linear increase in the vibrational transition rate constants, which is accompanied by a decrease in the rotationally inelastic transition rate constant. The total inelastic rate constant increases with upsilon(i) only at the highest values of vi. Net vibrational energy transfer [Delta E] calculated using rotationally summed rate constants is qualitatively consistent with a simple model. However, explicit inclusion of rotation gives quite different values of [Delta E]. The experimental results are compared with our three-dimensional trajectory calculations on an ab initio potential surface and on a simple repulsive potential surface.
Keywords:ROTATIONALLY INELASTIC-COLLISIONS;ATOM-DIATOM SCATTERING;STATE CROSS-SECTIONS;RATE CONSTANTS;TIME SPECTROSCOPY;EXCITED-STATES;DIPOLE-MOMENT;GROUND-STATE;LI-2;AR