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Manuscript Title: Fine structure cross sections from reactance matrices.
Authors: H.E. Saraph
Program title: JAJOM
Catalogue identifier: AAGJ_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 3(1972)256
Programming language: Fortran.
Computer: IBM 360/65.
Operating system: OS 360.
RAM: 40K words
Word size: 32
Keywords: Atomic physics, Scattering, Inelastic, Cross section, Reactance matrix, Russell saunders, Coupling, Jj coupling, Fine structure Transitions, Energy levels, Collision strength, Racah coefficient, Electron.
Classification: 2.4.

Nature of problem:
The reactance matrices obtained from calculations in SL coupling are transformed to compute collision strengths for transitions between fine structure levels.

Solution method:
The data which follow the same conventions as described in Comp. Phys. Commun. 1(1970)232. are sorted and checked. The R-matrices are trans- formed to pair coupling using algebraic recoupling coefficients. Moreover, the R-matrices may be transformed to allow for intermediate coupling in the target if the required transformation coefficients are available. The collision strengths are computed from the R-matrices using matrix algebra.

The array lengths should be adjusted to suit the user's problem and the core available on his computer. The algebraic transformations may introduce numerical inaccuracies for angular momenta >15, if single precision is used.

Unusual features:
On the 360/65, use of double precision is recommended. Instructions are given for conversion to single precision. Elaborate checks are made by the program at all stages of the computations and detailed error messages are printed. Use of the MACRO processor is recommended. The SCOPE CHECKPOINT/RESTART can easily be introduced, a suitable spot is marked in MAIN by a comment card.

Running time:
The sample data, comprising one energy, 6 target terms with summation over 20 intermediate states, took 2 min.