HYPERFINE-STRUCTURE STUDIES IN THE 6S 6P P-3(2)-LEVEL OF BARIUM

The hfs of the 3P2 state of the 6s 6p configuration of atomic barium has been determined for Ba-137, applying the collinear fast-beam laser spectroscopy. The data fill the last gap in the experimental information on low lying 6s2, 6s 6p, 6s 5d and 6p 5d configurations of this alcaline earth system. The results are analyzed in terms for the existing semi-empirical modified Breit-Wills theory (MBWT), working with two basic wave functions, as well as by an extension to six-component wave functions of inclusion of configuration interaction. The semi-empirical approaches lead to a consistent description of the different hyperfine structures; they are compared with the results from recent ab initio multiconfiguration Dirac Fock calculations.