Аннотация:Among other alkali diatomics the KRb molecule demonstrates a high density
of the low-lying electronic states arisen from close energy of the K and Rb
atoms in their first excited 2 P states. The adiabatic states are mutually per-
turbed due to the pronounced spin-orbit effect induced by heavy Rb atom and
strong configuration interaction. A global deperturbation analysis is appar-
ently required to represent the observed energies and radiative properties of
the excited KRb states with the spectroscopic accuracy.
Here we present R-depended spin-orbit matrix elements ab initio calculated
between all electronic states converging to the lowest four dissociation lim-
its. The relevant quasi-relativistic matrix elements accompanied by the adia-
batic potential energy curves were evaluated for a wide range of internuclear
distances and density grid in the basis of the spin-averaged wave functions
corresponding to pure Hund’s coupling case (a). Both shape and energy con-
sistent small (9-electrons) effective core pseudopotentials were used to monitor
a sensitivity of the matrix elements to the particular basis set. The dynamic
correlation has been taken accounted by a large scale multi-reference configura-
tion interaction method which was applied for only two valence electrons. The
l-independent core-polarization potentials of the both atoms were employed
to take into account the residual core-valence effect.
The achieved accuracy of the present ab initio functions is discussed by a com-
parison with preceding calculations 1 and their empirical counterparts 2 corre-
sponding to the observed spin-orbit splitting between different Ω-components
of the triplet (1) 3 Σ + and (1-3) 3 Π states.
All electronic structure calculations were performed with the Molpro package 3 .
The present work was supported by the RFBR under Grant No. 13-03-00466-
a.