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Manuscript Title: Inelastic molecule-corrugated surface scattering using the close- coupling wave packet method.
Authors: R.C. Mowrey, D.J. Kouri
Program title: CCWPSURF
Catalogue identifier: ABTS_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 63(1991)100
Programming language: Fortran.
Computer: VAX 6310.
Operating system: VMS 5.1, COS 1.17.
RAM: 58K words
Word size: 64
Keywords: Molecule-surface, Scattering, Elastic, Time-dependent wave Packet, Close-coupling wave Packet, Diffractive scattering.
Classification: 16.7.

Nature of problem:
The transition probabilities are calculated for rotationally and translationally inelastic scattering of a homonuclear diatomic molecule from a static, corrugated surface with a rectangular surface unit cell.

Solution method:
The wave function for the molecule is expanded in a series of rotational basis functions multiplied by time-dependent translational functions representing the center-of-mass motion. Each translational function is described by its values at the points of a three-dimensional grid. The initial wave function is written as a wave packet and is propagated in time using an expansion of the time-evolution operator in a series of Chebyshev polynomials. Evaluation of the operation of the kinetic energy term of the Hamiltonian on the wave function is calculated by using the fast Fourier transform. After the propagation is completed transition probabilities are obtained by determining the moments of the asymptotic states of the Hamiltonian with the final wave function.

Restrictions:
The program, as written, only allows the use of a particular functional form for the interaction potential. Other types of potentials can be used by making the appropriate modifications to the program. Larger problems can be treated by increasing the size of the parameter MXCORE in the main program.

Unusual features:
The program requires the use of the IMSL Library (Edition 9.2) routines MMBSJN, to calculate the values of Bessel functions of the first kind, and FFT3D, to calculate the value of the three-dimensional fast Fourier transform and its inverse.

Running time:
Running time for the test run on a VAX 6310 is approximately 92 minutes. The same calculation on a single processor of a Cray X-MP requires six minutes.