Adiabatic and diabatic representations of potential energy curves for the (NaRb)(+) system

Potential energy curves of (NaRb)(+) are investigated by an ab initio one-electron approach. The inner electrons are modelled by non-empirical relativistic pseudopotentials. The core polarization potential is included and the deviation of the core-core interaction from 1/R has been corrected. The spectroscopic constants of the ground (1(2) Sigma(+)) and lowest excited bound states (2(2) Sigma(+), 3(2) Sigma(+), 4(2) Sigma(+), 1(2) Pi) are derived. From an analysis of the adiabatic electronic wavefunctions a qualitative diagram of diabatic electronic energies in the range of internuclear distances (4-40 a(0)) is made. A diabatic electronic basis for the (NaRb)(+) molecular system is defined and electrostatic coupling matrix elements have been calculated.