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Manuscript Title: Transport and relaxation cross-sections for pure gases of linear molecules.
Authors: E.L. Heck, A.S. Dickinson
Program title: TRAJECT
Catalogue identifier: ADDE_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 95(1996)190
Programming language: Fortran.
Computer: IBM RS6000-355, IBM 380.
Operating system: AIX 3.2.5, Sun OS 5.4, HP-UX A.09.01.
RAM: 4M words
Word size: 32
Peripherals: disc.
Keywords: Thermophysical Properties, Rigid rotor, Classical trajectory, Generalized cross Sections, Thermal average, Molecular physics, Scattering, Elastic.
Classification: 16.7.

Nature of problem:
To calculate thermally averaged generalized cross-sections of a pure gas of linear molecules.

Solution method:
The program calculates thermally averaged generalized cross-sections of a pure gas of molecules which can be treated as rigid rotors. The 10- dimensional integration required is performed in two stages: (i) the total energy integration using a Chebyshev interpolation scheme and an automatic integrator based on the Clenshaw-Curtis formula; (ii) the remaining 9-dimensional integration is approximated by a Monte Carlo sum over N classical trajectories. Each trajectory is calculated by numerical integration of Hamilton's equations in the radial momentum and distance and the action-angle variables of a two rigid rotor system, exploiting conservation of total angular momentum.

Unusual features:
Packages required: NAG; PVM3

Running time:
On IBM RS6000-355. TRJSEQ - 281 sec, XSECTP - 8 sec, ERGY - <1 sec. The run times depend on the number of trajectories, the mix of total energies relative to the well depth of the potential and the number of generalized cross- sections. Besides these scaleable dependencies, the run time of the trajectory program depends on the complexity of the generalized forces.