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Manuscript Title: A program to compute isotope shifts in atomic spectra.
Authors: C.F. Fischer, L. Smentek-Mielczarek, N. Vaeck, G. Miecznik
Program title: MCHF_ISOTOPE
Catalogue identifier: ACLF_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 74(1993)415
Programming language: Fortran.
Computer: VAX 11/780.
Operating system: VMS, Sun UNIX.
RAM: 514K words
Word size: 32
Peripherals: disc.
Keywords: Atomic physics, Structure, Tensor algebra, Mass shift, Field shift, Isotope shift.
Classification: 2.1.

Subprograms used:
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

Nature of problem:
This program is a part of the MCHF atomic-structure package and allows for calculations of the isotope shift for bound-state systems, which is induced by the finite mass (mass shift) and the finite charge distribution (field shift) of the nucleus.

Solution method:
The isotope effect on the total energy of an atomic state is treated as a small perturbation. The resulting energy shift is separated into the normal and specific mass shift and the field shift, whose computation requires the use of output files from the MCHF package. In the case of the specific mass shift, two equivalent forms; the gradient form and the "Slater" form are computed. For the field shift, the calculations of the electronic contributions are carried out for the s-orbitals; the monoelectronic matrix elements are directly connected with the slope at the origin of the radial distributions. The calculation is performed for a particular state in either the LS or LSJ coupling scheme, using the angular coefficients, stored in a INT.LST file, and expansion coefficients from the <name>.c or <name>.l and <name>.j files.

The MCHF_ISOTOPE program has the same restrictions concerning the dimensions of the arrays and the inclusion of a maximum of two overlap integrals as the rest of the MCHF package.

Running time:
The CPU time required for the isotope portion is 0.3 seconds for the first case and 0.5 seconds for the second case on a SUN SPARC-station 330.