Erikas Gaidamauskas

Tensorial form and matrix elements of the relativistic nuclear recoil operator

Within the lowest-order relativistic approximation (~v2/c2) and to first order in me/M, the tensorial form of the relativistic corrections of the nuclear recoil Hamiltonian is derived, opening interesting perspectives for calculating isotope shifts in the multiconfiguration Dirac?Hartree?Fock framework. Their calculation is illustrated for selected Li-, B- and C-like ions. This work underlines the fact that the relativistic corrections to the nuclear recoil are definitively necessary for obtaining reliable isotope shift values.

Multiconfiguration Dirac-Hartree-Fock calculations of the electric dipole moment of radium induced by the nuclear Schiff moment

The multiconfiguration Dirac-Hartree-Fock theory has been employed to calculate the electric dipole moment of the 7s6d {sup 3}D{sub 2} state of radium induced by the nuclear Schiff moment. The results are dominated by valence and core-valence electron correlation effects. We show that the correlation effects can be evaluated in a converged series of multiconfiguration expansions.

JAHN : A program for representing atomic and nuclear states within an isospin basis

A computer program is presented to deal with atomic and nuclear state functions within an isospin-coupled basis. Apart from the classification of the isospin bases states, the program JAHN supports the computation of the corresponding coefficients of fractional parentage as well as of the transformation matrices going from a LS-coupled to an isospin-coupled basis. In the future, these features may facilitate the treatment of atomic systems in order to obtain a deeper insight into the coupling of open-shell atoms and ions. The JAHN program has been designed for interactive work and is distributed as a MAPLE module.

Pecularities of spectroscopic properties of W{sup 24+}

We aim at demonstrating the feasibility of accurate theoretical studies of atoms and ions having complex electronic configurations, open f shell included, by combining the second quantization method in coupled tensorial form with a quasispin technique, leading to triple tensors (in orbital, spin, and quasispin spaces). The large-scale nonrelativistic and relativistic calculations of the 977 lowest energy levels of W{sup 24+}, accounting for correlation, relativistic, and quantum electrodynamics effects, demonstrate the high efficacy of the methods used. The accuracy of the LS- and jj-coupling schemes is discussed as well. The wavelengths of electric dipole transitions, their line strengths and transition probabilities, as well as the lifetimes of some lowest excited levels are also calculated. The authors hope that the success in theoretical studies of such complex ions will stimulate relevant experimental research, encouraging yet further progress in the theory.

Multiconfiguration Dirac-Hartree-Fock calculations for the hyperfine-structure parameters and the scalar-pseudoscalar interaction constant of 133Cs

The 9th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas

Weak- and hyperfine-interaction-induced 1s2s 1S0-1s2 1S0 E1 transition rates of He-like ions

Weak- and hyperfine-interaction-induced 1s2s 1S0 → 1s2 1S0 E1 transition rates for the isoelectronic sequence of He-like ions have been calculated using the multi-configuration Dirac–Hartree–Fock (MCDHF) and relativistic configuration interaction methods. The results should be helpful for the future experimental investigations of parity non-conservation effects.