Elsevier Science Home
Computer Physics Communications Program Library
Full text online from Science Direct
Programs in Physics & Physical Chemistry
CPC Home

[Licence| Download | New Version Template] aacf_v1_0.gz(7 Kbytes)
Manuscript Title: The calculation of absorption and elastic cross sections using the optical potential.
Authors: A.C. Allison
Catalogue identifier: AACF_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 3(1972)173
Programming language: Fortran.
Computer: CDC 6400.
Operating system: SCOPE 3/35.
RAM: 13K words
Word size: 60
Keywords: Atomic physics, Potential, Complex potential, Optical model, Optical potential, Schrodinger equation, Numerov, Scattering, Absorption, Cross section, Phase shift, Other.
Classification: 2.6.

Nature of problem:
The absorption of particles by a centre of force may be represented by introducing a complex potential. The absorption and elastic cross sections are given in terms of the real and imaginary parts of the phase shift obtained from the solution of the Schrodinger equation with a complex potential.

Solution method:
This program is similar to one published earlier by Smith that also allows scattering by a complex potential to be studied. The present program permits greater flexibility in the form of the potential and also uses an improved Numerov scheme for integrating the differential equations.

The program can be easily modified to accept non-Coulomb potential energy functions of any form rather than the complex spherical well that is used in this version.

Unusual features:
The computation time of the numerical integration is halved because of the symmetry of the problem and the use of the iterative Numerov method.

Running time:
The time depends critically on the number of points in the integration mesh. For the test case, which required two hundred points, three complex phases were generated each s.