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Manuscript Title: Computation of cross sections and polarizations for nuclear reactions, in which only spin 1/2 particles are involved.
Authors: P. Heiss
Program title: S 1/2 PARTICLE CS AND POL
Catalogue identifier: ABGK_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 4(1972)371
Programming language: Fortran.
Computer: IBM 370/165.
Operating system: OS.
RAM: 11K words
Word size: 32
Keywords: Nuclear physics, M-matrix, Phase shifts, Nuclear reactions, Cross sections, S-matrix, Polarization.
Classification: 17.8.

Nature of problem:
Both for a phase shift analysis and for reaction calculations one needs to relate cross sections, polarization values etc. on the one hand and S-matrix elements in the usual lsJ representation on the other. For general cases this calculation requires great computational effort. For reactions in which only spin 1/2 particles are involved this effort can be considerably reduced, by the explicit calculation of the M-matrix.

Solution method:
In the special case under discussion, relatively simple relations between S-matrix elements and M-matrix elements can be derived. From M- matrix elements, cross sections and polarizations can be obtained in a simple way. Hence, the following program requires only a small amount of high speed storage space and runs relatively fast.

Restrictions:
The program is restricted to a maximum angular momentum of L=3. If higher partial waves are included, dimensions of certain arrays have to be increased. These arrays are specified in section 3 of the "long write-up".

Running time:
Half a second per energy value.