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Manuscript Title: A programming package for the calculation of cross-sections and probabilities for charge-exchange processes.
Authors: J. Van den Bos
Program title: IPFVAIJ
Catalogue identifier: ACRP_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 7(1974)163
Programming language: Fortran.
Computer: IBM 360/65.
Operating system: HASP/OS 360 MVT.
RAM: 23K words
Word size: 32
Peripherals: magnetic tape, disc.
Keywords: Atomic physics, Collision, Molecular physics, Charge transfer, Capture electron, Interaction matrix Elements, Overlap matrix elements, Double numerical Quadrature.
Classification: 16.8.

Nature of problem:
When two atomic or molecular species collide there is a finite probability that they exchange electrons. In this communication we describe a method that results in probabilities and cross-sections for the process in which one of the particles captures an electron from the other one. The method is restricted to relative kinetic energies appreciably larger than the energy deficit of the reaction.

Solution method:
A finite-state expansion of the total wave function involved, when substituted in the Schrodinger equations, gives rise to a system of coupled linear differential equations, under the assumption of a straight-line trajectory for the projectile. IPFVAIJ computes the interaction and overlap matrix elements for the two reactants involved, while IPFDEQ solves the coupled equations as a function of impact parameter and kinetic energy of the projectile using a predictor- corrector method.

The package has no restrictions on the kind of atoms or molecules involved except that it can only solve the following combinations of electronic spectral states: l1 =0, l2=0; l1=0, l2=1; l1=1, l2=0.