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Manuscript Title: The MCHF atomic-structure package.
Authors: C.F. Fischer
Program title: ATSP_MCHF version 1.00
Catalogue identifier: ADLY_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 128(2000)635
Programming language: Fortran.
Computer: SUN Ultra 1, Pentium-based PCs.
Operating system: Sun UNIX OS 5.2, LINUX 2.2.10.
RAM: 64M words
Word size: 32
Peripherals: disc.
Keywords: Atomic physics, Structure, Multiconfiguration Hartree-Fock (MCHF), Configuration Interaction, Correlation, Bound states, LS coupling, Breit-Pauli, Isotope shifts, Hyperfine interactions, Oscillator strengths, Transition rates, Autoionization, Photoionization.
Classification: 2.1.

Other versions:
Cat Id Title Reference
ABZU_v1_0 MCHF_LIBRARIES CPC 64(1991)399
ABZV_v1_0 MCHF_GENCL CPC 64(1991)406
ABZW_v1_0 MCHF_NONH CPC 64(1991)417
ABZX_v1_0 MCHF_88 CPC 64(1991)431
ABZY_v1_0 MCHF_BREIT CPC 64(1991)455
ABZZ_v1_0 MCHF_CI CPC 64(1991)473
ACBA_v1_0 MCHF_MLTPOL CPC 64(1991)486
ACLD_v1_0 MCHF_AUTO CPC 74(1993)381
ACLE_v1_0 MCHF_HFS CPC 74(1993)399
ACLF_v1_0 MCHF_ISOTOPE CPC 74(1993)415

Nature of problem:
This package determines the energy and associated wave functions for states of atoms and ions in the multiconfiguration Hartree Fock (MCHF) approximation. Once radial functions have been determined, relativistic effects may be included through the diagonalization of the Breit-Pauli Hamiltonian. Given a wve function, various atomic properties can be computed such as E1, E2, .., M1, M2, ... transitions between LS or LSJ states, isotope shift constants, and hyperfine interactions. Autoionization and simple photoionization calculations can also be performed.

Solution method:
Wavefunctions are obtained using variational methods leading to systems of differential equations for radial functions and the matrix eigenvalue problem for expansion coefficients of configurations states. The radial functions are obtained using finite difference methods.

Reasons for new version:
The previoius version was published as a series of programs, each associated with specific co-authors. In this, the entire package is collected into a directory structure with a make_atsp script that illustrates how the application can be generated. Intel PC executables are provided for PC users who do not have a FORTRAN compiler. Included also is a simple continuum MCHF program [1] with one open channel and an associated photoionization program. Use of the program is described in the book [2].

Summary of revisions:
Previously published programs together with two unpublished programs have been collected and placed either in lib_src or atsp_src source directories that include makefiles for the different objects. A test_run directory has been added with script files that, when executed produce, results that can be checked with similar information in the results directory. The make directory contains a make_atsp that will make the applications on many platforms.

The restrictions are those of the previous publications. The README file explains the different parameter statements that determine the size of the problem. Many restrictions may be relaxed by changing the value of parameter statements, but the restriction of a maximum of 5 open shells is not easily overcome. A limited amount of non-orthogonality of orbitals is allowed.

Unusual features:
Intel PC executables are provided for those without a FORTRAN compiler running the LINUX operating system. Background theory for the execution of the various applications is presented in a book [2] with selected examples. A limited amount of non-orthogonality between orbitals is allowed in the calculation of atomic properties.

Running time:
A single and double double replacement expansion from the 2s22p23P term of carbon to the orbitals 2p, 3s, 3p, 3d leading to 69 configuration states, required a total of 3.0 seconds for both angular and radial calculations on a SUN Ultra 1.

[1] C. Froese Fischer and Jinhua Xi (unpublished).
[2] C. Froese Fischer, T. Brage, and Per Jonsson, Computational Atomic Structure: An MCHF Approach, Institute of Physics (Bristol) 1997.