Theory of collisional energy transfer - bromine in low-density inert gases

Abstract

Classical binary collision trajectory calculations have been carried out to study the energy transfer efficiency between the internal degrees of freedom of highly energized bromine (Br 2) and the translation degrees of freedom of an inert gas (He, Ne, Ar, Kr, Xe) in the low-density limit. The dependence on species (mass, strength of attraction), temperature of the gas ( T = 160, 300, and 1500 K) and internal energy of the bromine (14, 28, 43 kcal/mole; E d = 45.5 kcal/mole) is considered. Global statistical theories overestimate the average energy transferred per collision by an order of magnitude or more. A simple impulsive collision theory is developed and found to account for the magnitudes (typically within a factor of 2–3) and the gross-trends to reasonable accuracy.