Theoretical studies of collisional energy transfer in highly excited molecules: temperature and potential surface dependence of relaxation in He, Ne, Ar + Cs/sub 2/
In this paper the authors use the redistributed successive collision (RSC) method and a related method based on single energy collisions (SEC) to study the relaxation of CS/sub 2/ by He, Ne, and Ar. For He + CS/sub 2/ they examine the temperature dependence of the average vibrational energy transfer (..delta..E) and find that, at 36,000 cm/sup -1/, (..delta..E) increases monotonically with T between 300 and 2000 K. The temperature dependence is similar but stronger for Ne + CS/sub 2/ and Ar + CS/sub 2/. All of their results at 36,000 cm/sup -1/ are in agreement with experiment within the experimental uncertainties. The dependence of (..delta..E) on the average vibrational energy (E) of CS/sub 2/ is approximately linear for He + CS/sub 2/ and Ne + CS/sub 2/ at all temperatures and for Ar + CS/sub 2/ at 1000 K. They also consider the dependence of (..delta..E) on the potential surfaced used in the trajectory simulations. For the CS/sub 2/ intramolecular potential, they consider three surfaces: harmonic, sum of Morse functions, and a many-body expansion surface. They find that (..delta..E) for He + CS/sub 2/ is insensitive to which surface they use. For the intermolecular potential they consider exponential-spline-Morse-spline-van der Waals (ESMSV) pair potentials and Lennard-Jones 6-12 and 6-20 pair potentials. They study the effect of well depth and repulsive wall steepness for the He + CS/sub 2/ system and find that different parametrizations of the potentials and variation of the van der Waals well depths lead to the same (..delta..E)'s; however, an increase in steepness (as in changing from 6-12 to 6-20 potentials) leads to a significant change in (..delta..E).
- Research Organization:
- Northwestern Univ., Evanston, IL (USA)
- OSTI ID:
- 6222587
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 92:26
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ARGON
ENERGY TRANSFER
CARBON SULFIDES
HELIUM
NEON
ATOM-MOLECULE COLLISIONS
TEMPERATURE DEPENDENCE
THEORETICAL DATA
VIBRATIONAL STATES
ATOM COLLISIONS
CARBON COMPOUNDS
CHALCOGENIDES
COLLISIONS
DATA
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
INFORMATION
MOLECULE COLLISIONS
NONMETALS
NUMERICAL DATA
RARE GASES
SULFIDES
SULFUR COMPOUNDS
400201* - Chemical & Physicochemical Properties