CI-MBPT: A package of programs for relativistic atomic calculations based on a method combining configuration interaction and many-body perturbation theory

Abstract

This package of programs allows us to carry out relativistic calculations for many-electron atoms and ions. One can find energy levels and a number of atomic properties: g-factors, magnetic-dipole and electric-quadrupole hyperfine structure constants, electric- and magnetic-multipole transition amplitudes, and matrix elements of the parity nonconserving interactions. Method of calculation is based on a combination of conventional configuration interaction (CI) method and many-body perturbation theory (MBPT). The former explicitly accounts for the interaction between valence electrons, while the latter includes core–core and core–valence correlations. These two methods are combined to acquire benefits from both approaches and attain better accuracy. Program summaryProgram title: CI-MBPTCatalogue identifier: AEWV_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEWV_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 102640No. of bytes in distributed program, including test data, etc.: 583539Distribution format: tar.gzProgramming language:Fortran 90.Computer: Intel Core i5 CPU, 3.2 GHz.Operating system: Linux (CentOS 5, Ubuntu 12.04 LTS, SUSE 13.2).RAM: 8 GbClassification: 2.1.Nature of problem: Prediction of atomic or ionic energy levels and different observables in the framework of relativistic approach.Solution method: The package of programs determines energy levels and associated many-electron wave functions for states of atoms and ions in the pure CI or CI+MBPT approximations. Using the wave functions, different atomic properties can be obtained, including g-factors, magnetic-dipole and electric-quadrupole hyperfine structure constants, electric- and magnetic-multipole transition amplitudes, P-odd and P,T-odd amplitudes.Restrictions: The package is not designed for calculations of high Rydberg and autoionizing states. It becomes inefficient for the number of valence electrons exceeding four or five. It has not been tested for superheavy elements. The maximal number of Hartree–Fock–Dirac (HFD) orbitals when HFD equations are solved is 32.Unusual features: One-electron orbitals outside the nucleus are defined on radial grid points. Inside the nucleus they are described in a form of the Taylor expansion over r/R, where R is the nuclear radius.Additional comments: All programs have been compiled, linked, and tested with both “ifort” and freely available “gfortran”.Running time: Changes from tens of minutes for atoms with two valence electrons to tens of hours for more complex systems.