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

Abstract

a b s t r a c tThis 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 electricquadrupole 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 summary Program title: CI-MBPT Catalogue identifier: AEWV_v1_0Program summary URL: 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 ✩ This paper and its associated computer program are available via the Computer Physics Communication homepage on ScienceDirect (S.G. Porsev). http://dx.doi.org/10.1016/j.cpc.2015.05.007 0010-4655/© 2015 Elsevier B.V. All rights reserved.2 M.G. Kozlov et al. / Computer Physics Communications ( ) -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.

Correlation, Breit, and QED effects in spectra of Mg-like ions

“…They also should not be included in the CI+MBPT calculations. Note that this significantly simplifies calculations with the package [32].…”

Calculation of Francium Hyperfine Anomaly

“…Core-valence and core-core electron correlations were taken into account within the DHF + MBPT method [7]. Electron correlation corrections significantly change A 0 values.…”

“…Thus, the development of the new methods of atomic calculations of the hyperfine constants accounting for the HFA becomes relevant and timely [6]. Below, we discuss how to calculate HFA for many-electron atoms with available atomic package [7], which is based on the original Dirac-Hartree-Fock code [8]. This package has often been used to calculate different atomic properties including HFS constants of Tl [9][10][11] and Pb [12].…”

Prediction of quantum many-body chaos in the protactinium atom

“…We use a CI package described in [31] to model overall statistical properties of lower energy levels of Pa. Hartree-Fock-Dirac one-electron functions φ i are generated for the configuration [Rn] 5f 2 6d 1 7s 2 7p 0 . The φ i of valence electrons are built in the field of frozen [Rn] core.…”