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Manuscript Title: PIRK: a computer program to calculate the elastic scattering of pions from nuclei.
Authors: R.A. Eisenstein, G.A. Miller
Program title: PIRK
Catalogue identifier: ABCJ_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 8(1974)130
Programming language: Fortran.
Computer: UNIVAC 1108.
Operating system: UNIVAC EXEC II.
RAM: 22K words
Word size: 36
Keywords: Nuclear physics, Pion, Elastic scattering, Angular distribution, Nuclear optical model, Klein-gordon, Runge-kutta, Complex potential, Phase shift, Cross-section, Medium energy.
Classification: 17.14.

Other versions:
Cat Id Title Reference
AAWC_v1_0 PIRK 2 CPC 16(1979)389

Nature of problem:
Angular distributions for the elastic scattering of pions from optical potential representations of the nucleus are generated from the partial wave expansion of the scattering amplitude. Complex phase shifts for each partial wave are obtained by numerically integrating the radial Klein-Gordon equation in the interior region and matching to the asymptotic Coulomb wavefunction in the exterior region. The integration is done using the fourth-order Runge-Kutta method. To insure accuracy, the program utilizes double precision arithmetic. Several optical potentials and nuclear densities are available in the program.

Solution method:
Angular distributions for the elastic scattering of pions from optical potential representations of the nucleus are generated from the partial wave expansion of the scattering amplitude. Complex phase shifts for each partial wave are obtained by numerically integrating the radial Klein-Gordon equation in the interior region and matching to the asymptotic Coulomb wavefunction in the exterior region. The integration is done using the fourth-order Runge-Kutta method. To insure accuracy, the program utilizes double precision arithmetic. Several optical potentials and nuclear densities are available in the program.

Restrictions:
A maximum of 50 partial waves may be included in the scattering amplitude without changing the program. The program presently treats only a restricted class of non-local potentials; other types of non- localities may be of physical interest. The finite size, spherical nuclear charge density is that of a uniform sphere.

Running time:
Depends on the number of integration steps per partial wave and the number of partial waves. The test case given requires 2.9 s on the UNIVAC 1108. (15 partial waves, 200 integration steps per partial wave.)