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Manuscript Title: A multi-configuration Hartree-Fock program with improved stability.
Authors: C.F. Fischer
Program title: MCHF72
Catalogue identifier: ACRF_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 4(1972)107
Programming language: Fortran.
Computer: S360/75.
Operating system: OS/360-MVT, HASP II.
RAM: 53K words
Word size: 32
Keywords: Atomic physics, Structure, Numerical hartree-fock, Configuration Interaction, Bound state, Schrodinger equation, Self-consistent field, Energy level.
Classification: 2.1.

Other versions:
Cat Id Title Reference
ACQJ_v1_0 MULTI-CONFIGURATION HARTREE-FOCK CPC 1(1969)151
ACYA_v1_0 MCHF77 CPC 14(1978)145
AATK_v1_0 HF86 CPC 43(1987)355

Revision history:
Type Tit le Reference
correction 000ACORRECTION 2/01/74 See below

Nature of problem:
Numerical non-relativistic Hartree-Fock results are determined within the multi-configuration approximation for atoms in a bound state.

Solution method:
The self-consistent field method of solution is employed. In a multi- configuration calculation the mixing coefficients are adjusted periodically as part of the SCF iteration. Two new methods are used for the solution of the differential equations. Otherwise the program is essentially the same as MULTI-CONFIGURATION HARTREE-FOCK but with improved accuracy and efficiency. The orthogonality conditions Integral P(nl;r)P(n'l;r)dr = delta nn'' may be applied to either functions within a configuration or else all functions. These conditions lead to off-diagonal energy parameters in the Hartree-Fock equations.

Restrictions:
The possible configurations are restricted to those for which the interactions can be expressed as either Fk, Gk, or Rk integrals. This excludes certain singly substituted configurations which frequently would result in an indeterminate systems of equations. Also, since bound states in the continuum interact most strongly with continuum states, a multi-configuration calculation for such states cannot be per- formed with this program.

Unusual features:
The organization of the program is such that the "frozen core" approximation may be used and orbitals with zero occupation number are allowed.

Running time:
The CPU time for a series of cases consisting of (i) the two- configuration approximation for C**2+, B+ and Be 1S (ii) Na 3p 2P (iii) Na 3s 2S with 1s, 2s, 2p"frozen" (iv) Na 4s 2S with 1s, 2s, 2p"frozen" and the 3s having a zero occupation number required 1.06 min on an IBM 360/75.

CORRECTION SUMMARY
Manuscript Title: A multi-configuration Hartree-Fock program with improved stability. (C.P.C. 4(1972)107).
Authors: C.F. Fischer
Program title: 000ACORRECTION 2/01/74
Catalogue identifier: ACRF_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 7(1974)236
Classification: 2.1.