RELAXATION OF HIGHLY VIBRATIONALLY EXCITED KBR BY AR

Exact formulation of the impulse approach, also known as the quantum-mechanical spectator model, is used to investigate the rapid deactivation of highly internally excited KBr, written as KBr**, by Ar-a phenomenon not previously understood. The model of inelastic scattering at the repulsive wall, approximated here by a hard-core potential, using the impulse formalism is compared with the experimentally observed results obtained by scattering KBr** with Ar. The calculation is in excellent agreement with the measured results for the 75-degrees center-of-mass (c.m.) scattering angle, while the calculated results for the 45-degrees c.m. scattering near the peak (nearly elastic scattering) are a factor of about 1.5 smaller than the measured results. This is an impulse calculation where the collision energy is supplied by the internal motion of the target and not by the translational motion of the projectile.