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Manuscript Title: An atomic multiconfigurational Dirac-Fock package.
Authors: I.P. Grant, B.J. McKenzie, P.H. Norrington, D.F. Mayers, N.C. Pyper
Program title: MCDF
Catalogue identifier: AANC_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 21(1980)207
Programming language: Fortran.
Computer: IBM 360/195.
Operating system: OS/360, HASP.
Program overlaid: yes
RAM: 344K words
Word size: 8
Peripherals: magnetic tape, disc.
Keywords: Atomic physics, Racah, Structure, Multiconfiguration, Fractional parentage, Dirac-fock, Recoupling coefficients, Slater integrals, Complex atoms, Relativistic, Dirac equation, Jj-coupling, Methods theoretical.
Classification: 2.1.

Revision history:
Type Tit le Reference
adaptation 0001 CONTWV See below

Nature of problem:
The relativistic Dirac-Fock equations are set up and solved numerically within the framework of the multiconfiguration approximation. This provides energy eigenvalues and orbital wavefunctions that can be used to calculate various atomic properties.

Solution method:
Atomic state functions are constructed from a linear combination of configuration state functions which are eigenfunctions of J**2, Jz and parity. These in turn are built from single-electron central field spinors. The self-consistent field approach results in coupled first- order differential equations for the orbital wavefunctions. These are solved iteratively using the method described by Desclaux, Mayers and O'Brien within the context of various schemes for rending the energy stationary.

Restrictions:
The present version of the program is restricted to 25 orbitals, 30 configurations with up to 350 grid points per orbtial. These values may be increased by increasing the storage of the relevant arrays. The limit on the number of coefficients generated by the MCP package is set at 500. Integrals of the form I(ab) have been included in the Hamiltonian matrix but are not incorporated into the orbital equations. Code to force orthogonality of two orbitals with the same angular characterand identical occupation numbers has been included. This does not always result in a solution unless the system is near convergence; however, it is possible to set an option to relax this restriction, often resulting in approximately orthogonal orbitals which are then Schmidt orthogonalized.

Unusual features:
The program includes useful features such as the recording of data set names, providing time and date of run, and the introduction of a timing scheme to save information on tape or disc if the program exceeds its cpu-time requests. These are implemented using local system routines which have been clearly indicated to allow the user to replace them if necessary. All routines use double precision arithmetic.

Running time:
Running time ranges from a few seconds for a small single configuration atom to about ten minutes for a many-configuration large atom, on an IBM 360/195. The four examples in the test deck took 149 s using the G- compiler and 47 s using the H extended plus compiler.

ADAPTATION SUMMARY
Manuscript Title: Relativistic continuum wavefunction solver.
Authors: W.F. Perger, V. Karighattam
Program title: 0001 CONTWV
Catalogue identifier: AANC_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 66(1991)392
Programming language: Fortran.
Computer: SUN SPARC STATION.
Classification: 2.1.

Subprograms used:
Cat Id Title Reference
AANC_v1_0 MCDF CPC 21(1980)207

Nature of problem:
The relativistic Dirac-Fock equations are set up and solved numerically for continuum wave functions within the framework of the program of Grant, et al. (C.P.C. 21(1980)207).

Solution method:
Relativistic atomic wave functions are calculated using a central differences method with deferred corrections within the configuration interaction framework of the Grant et al program. Lagrange multipliers are automatically calculated without additional input.

Restrictions:
The adaptation is restricted for very large energies (greater than 100 atomic units) only due to the demands on memory caused by the rapid oscillation of the wavefunction and the subsequent need for more grid points (currently 2000).

Unusual features:
The program will calculate a virtual state V**N-1 continuum orbital for a given k quantum number and dump that orbital to a file.

Running time:
The typical running time is 20 seconds to 20 minutes.