Secondly Quantized Multi-Configurational Approach for Atomic Databases

Studies of the structure of atoms and ions (ultracold to relativistic included) as well as their twobody interactions with photons, electrons and other particles require accurate methods for the description of such objects. In order to obtain accurate values of atomic quantities it is necessary to account for relativistic and correlation effects. Relativistic effects may be taken into account as Breit-Pauli corrections or in a fully relativistic approach. In both cases for complex atoms and ions, a considerable part of the effort must be devoted to integrations over spin-angular variables, occurring in the matrix elements of the operators under consideration. Many existing codes for integrating are based on a scheme by Fano [1]. The integrations over spin-angular variables in this case constitute a considerable part of the problem, especially when atoms with many open shells are treated, and the operators are not trivial. In the papers of Gaigalas et al [2, 3], the efficient approach for finding matrix elements of any oneand two-particle atomic operator between complex configurations is suggested. It is free of shortcomings of previous approaches. This approach allows one to generate fairly accurate databases of atomic parameters (Froese Fischer et al [4, 5]). Further development of the approaches by Gaigalas et al [2, 3] for the spin-spin and spin-otherorbit relativistic corrections in the Breit-Pauli approximation is presented in this poster.