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Manuscript Title: ISICS: a program for calculating K-, L- and M-shell cross sections from ECPSSR theory using a personal computer.
Authors: Z. Liu, S.J. Cipolla
Program title: ISICS
Catalogue identifier: ADDS_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 97(1996)315
Programming language: C.
Computer: IBM with 80386 32-bit.
Operating system: MS-DOS 3.3 and higher systems.
RAM: 4MBK words
Word size: 32
Keywords: Atomic K-, L-, M-Shell ionization, PWBA and ECPSSR cross sections, Direct coulomb excitation, Ion-atom collisions, X-ray production cross Sections.
Classification: 16.7.

Nature of problem:
The cross section for atomic inner-shell ionizatin by accelerated positive ions is most commonly described by the plane wave Born approximation (PWBA) with perturbed stationary state corrections for ion-induced binding and polarization effects, Coulomb deflection of the ion's trajectory and relativity (ECPSSR). ISICS is a stand-alone package that uses Gauss-Legendre quadrature integration to obtain the form factors to calculate PWBA and ECPSSR K-, L- and M-shell cross sections for any projectile/atom combination. Besides ionization cross sections, ISICS also calculates x-ray production cross sections. Databases built into the program are easily changed.

Restrictions:
ECPSSR M-shell cross sections are calculated only approximately in that a united atom approach is used to calculate the binding effect and no relativity corrections are employed. This is due to lack of published theory to do these calculations. The contribution to the ionization cross section from electron capture by the projectile is not included in any calculations.

Unusual features:
The only input required is to follow the menu to enter the projectile, the target atom, the projectile energy range and increment and to select the Gauss-Legendre quadrature order (50 is considered standard).

Running time:
This depends on which shell and the number of different energies to be used in the calculation. For example, to calculate K-shell cross sections for protons striking carbon for 19 different proton energies it took less than 10 s; to calculate M-shell cross sections for protons on gold for 21 proton energies it took 4.2 min.