EFFECT OF MULTIPLE ENCOUNTERS ON VIBRATIONAL TO TRANSLATIONAL ENERGY-TRANSFER

Vibrational to translational energy transfer was studied computationally and analytically for collinear, impulsive collisions with square well oscillators, harmonic oscillators, and Morse oscillators. At a fixed temperature T the average number of encounters is between one and two if the vibrational energy E(v) is large compared to kT and (or) if the relative mass of the collider is small. If these conditions are met, [Delta E], the average energy transferred per collision, varies nearly linearly with E(v) over a wide range. If the average number of encounters is greater than two, [Delta E] as a function of E(v) has a more complicated form. The average final energy, [Delta E] + E(v) is less than what is predicted by the single encounter impulsive collision (SEI) model. Other things being equal, the ratio of the actual average final energy to the SEI average final energy is roughly the same for all of the above mentioned oscillators.