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Manuscript Title: A program for atomic wavefunction computations by the parametric potential method.
Authors: M. Klapisch
Program title: MAPPAC
Catalogue identifier: AAKC_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 2(1971)239
Programming language: Fortran.
Computer: UNIVAC 1108.
RAM: 50K words
Word size: 36
Keywords: Atomic physics, Radial Wave function, Transition probability, Central field, Spin-orbit coupling, Hyperfine structure Fitting.
Classification: 2.7.

Nature of problem:
MAPPAC computes atomic radial wavefunctions, and many related quantities, such as Slater integrals, spin-orbit coupling, mixing of configurations, hyperfine structure, transition probabilities etc., in the framework of first-order perturbation theory, built upon an optimized central field.

Solution method:
The central field is represented by an analytical expression in which some parameters are free. Given initial values of these, an iterative computation is performed, which optimizes the central field according to one of the following quality criteria (available as input options) (a) minimization of the r.m.s. deviation of the energy between theory and experiment ("spectroscopic criterion"); (b) minimization of the sum of total energies ("varitional criterion"); (c) minimization of the perturbing operator ("perturbational criterion")

Restrictions:
Wavefunctions are not relativistic, although first-order corrections to energies are computed. Continuum wavefunctions are not computed. Angular coefficients of integrals for open shells must be given as input. Maximum number of wavefunctions: 30; of matrices: 30; maximum rank: 30; number of integrals: 300. Kinds of integrals programmed: 17. Number of levels to be computed at a time: 200. Any atom or ion can be studied, except for those involving g-wave and higher wave electron orbitals.

Unusual features:
(a) On the physical aspect: the convergence of radial equations has been achieved in such a way that estimates of one electron energy parameters, or screening constants etc., are not required. (b) On the preparation of data input: it has been made easy by through use of alphabetic symbols in data, and checking punching errors as far as possible.