arXiv subjects

T. Zalandauskas

Publications and source records attributed to T. Zalandauskas.

4 recordsLinked to original sources

arXiv2004

Studies of Lanthanides 6s Ionization Energy

This work is aimed at the multi-configuration Hartree-Fock calculations of the 6s ionization energies of lanthanides with configurations [Xe]4f^{N}6s^{2}. Authors have used the ATSP MCHF version in which there are new codes for calculation of spin-angular parts of matrix elements of the operators of intraatomic interactions written on the basis of the methodology Gaigalas, Rudzikas and Froese Fischer, based on the second quantization in coupled tensorial form, the angular momentum theory in 3 spaces (orbital, spin and quasispin), graphical technique of spin-angular integrations and reduced coefficients (subcoefficients) of fractional parentage. This methodology allows us to study the configurations with open f-shells without any restrictions, thus providing the possibility to investigate heavy atoms and ions as well as to obtain reasonably accurate values of spectroscopic data for such complex many-electron systems.

physics.atom-ph↗

arXiv2004

Spectroscopic LSJ notation for atomic levels obtained from relativistic calculations

Today, relativistic calculations are known to provide a very successful means in the study of open-shell atoms and ions. But although accurate atomic data are obtained from these computations, they are traditionally carried out in jj-coupling and, hence, do often not allow for a simple LSJ classification of the atomic levels as needed by experiment. In fact, this lack of providing a proper spectroscopic notation from relativistic structure calculations has recently hampered not only the spectroscopy of medium and heavy elements, but also the interpretation and analysis of inner-shell processes, for which the occurrence of additional vacancies usually leads to a very detailed fine structure. Therefore, in order to facilitate the classification of atomic levels from such computations, here we present a program (within the Ratip environment) which help transform the atomic wave functions from jj-coupled multiconfiguration Dirac-Fock computations into a LS-coupled representation. Beside of a proper LSJ assignment to the atomic levels, the program also supports the full transformation of the wave functions if required for (nonrelativistic) computations.

physics.atom-ph↗

arXiv2004

Analytical expressions for special cases of LS-jj transformation matrices for a shell of equivalent electrons

Transformation matrices of the weights of the atomic wave functions in jj coupling to the relevant weights of LS coupling are considered for a shell of equivalent electrons. Their use allows one to preserve main part of relativistic effects but to classify the energy levels of an atom or an ion considered with the help of a set of quantum numbers of LS coupling scheme. Having in mind that the numerical values of the abovementioned transformation matrix (LS-jj) may be generally obtained in a very time consuming recurrent way, the analytical expressions of these matrices for a number of special cases of electronic configurations are presented.

physics.atom-ph↗

arXiv2004

Studies of Er ionization energy

This work is aimed at the multiconfigurational Hartree-Fock calculations of the Er ionization energy. Authors have used the ATSP MCHF version in which there are new codes for calculation of spin-angular parts written on the basis of the methodology Gaigalas, Rudzikas and Froese Fischer, based on the second quantization in coupled tensorial form, the angular momentum theory in 3 spaces (orbital, spin and quasispin) and graphical technique of spin-angular ntegrations. They allow the study of configurations with open f-shells without any restrictions and lead to fairly accurate values of spectroscopic data.

physics.atom-ph↗