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Manuscript Title: Self-consistent field Hartree-Fock program for atoms.
Authors: L.V. Chernysheva, N.A. Cherepkov, V. Radojevic
Program title: ATOMIC SCF HARTREE-FOCK
Catalogue identifier: AAKQ_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 11(1976)57
Programming language: Algol.
Computer: CDC 3600.
Operating system: SCOPE 6.3.
RAM: 32K words
Word size: 48
Peripherals: magnetic tape.
Keywords: Atomic physics, Structure, Energy level, Independent-particle Approximation, Single-particle model, Hartree-fock, (many-)electron correlations, Electron configuration, Single-configuration Approximation, Atomic shell, nl-(sub)shell, Self-consistent field, Iteration convergency Acceleration, Numerov method, Chasing method, Gauss elmination Method without pivoting, Energy eigenvalue Adjustment.
Classification: 2.1.

Nature of problem:
The present program calculates one-electron radial wave function and energy eigenvalues by solving non-relativistic single-configuration Hartree-Fock (HF) equations for bound states of an atom.

Solution method:
HF equations are solved by iterations until self-consistency is achieved. To stabilize the iteration process and to accelerate its convergence special procedures are applied. The differential equation, appearing in the iteration process, is solved using the Numerov method. The energy eigenvalue is so adjusted that the corresponding radial function satisfies the boundary conditions and has the required number of nodes.

Restrictions:
Off-diagonal parameters, which varnish for closed nl-subshells, are neglected in the present program. Therefore, the program could be used for configurations with the majority, if not all, closed nl-subshells, e.g., for the ground state configurations where these parameters and very small. For certain configurations with excited single-electron d or f states (like e.g., 20 Ca 4S4d(3D)) instabilities in solving the corresponding equation can occur, which prevent a solution being obtained.

Unusual features:
The present program is designed so that the results can be used directly as input data for another program, which calculates excited discrete and continum states. Consequently, the independent variable in both of these programs is related to the radial variable in both of these programs is related to the radial variable by the transformation x = alpha r + Beta 1nr,which for excited, especially continuum states, behaves suitably at large values of r, while at small values of r it has the usual logarithmic behaviour.

Running time:
For the ground state configuration of nitrogen 1s**22s**22p**3(**4S), with 700 integration points of the independent variable, the total running time including compilation amounts to about 10 minutes on a CDC 3600 computer with all peripherals connected on-line, and with the operating system (SCOPE) on a magnetic tape.