De-excitation and equipartition in H/sub 2/-surface collisions

Conference · Tue Nov 01 04:00:00 EST 1983

OSTI ID:5470293

Karo, A M; Hiskes, J R; Olwell, K D; DeBoni, T M; Hardy, R J

We have used computer molecular dynamics to study de-excitation of vibrationally-excited H/sub 2/ molecules undergoing repeated collisions with a wall maintained at some temperature T(W). We have calculated the average loss or gain of vibrational, rotational, translational, and total molecular energy as a function of the number of collisions for a statistically significant number of molecules having some initial vibrational state v'' ranging from v'' = 2 to v'' = 12. For initial translational and rotational temperatures around 500/sup 0/K, we have obtained a consistent picture of rapid vibrational de-excitation during the first collision, with a corresponding increase in translational kinetic energy and with rotational excitation from an initial J = 1 state up through values greater than J = 14. Wall collisions are found to provide an effective and rapid kinematic mechanism for V-T, V-R, and R-T energy transfer. The rate of loss of total molecular energy to the wall (accommodation) is discussed and compared with the rate of energy redistribution (equipartition) among the vibrational, rotational, and translational degrees of freedom of the molecules.

• Research Organization: Lawrence Livermore National Lab., CA (USA); Nebraska Univ., Lincoln (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5470293
• Report Number(s): UCRL-89586; CONF-831180-2; ON: DE84003008
• Country of Publication: United States
• Language: English

Related Subjects

640301* -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COLLISIONS
DE-EXCITATION
ELEMENTS
ENERGY LEVELS
ENERGY LOSSES
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
HYDROGEN
LOSSES
MOLECULE COLLISIONS
NONMETALS
VIBRATIONAL STATES