Theoretical investigation of barium-helium collisions .1. The adiabatic potential curves

Collisions between ground-state helium atoms and excited barium atoms in the (6p)P-3(J), (5d)D-1(2), and (5d)D-3(J) states are treated theoretically. Born-Oppenheimer potential curves are calculated with a combination of semiempirical model potentials and pseudopotentials to represent the interactions between the valence electrons of the barium atom and the closed-shell cores. The molecular basis set is constructed from numerical eigenstates of the Ba+ ion. Spin-orbit coupling is included explicitly in the e(-)-Ba2+ interaction Hamiltonian. We report higher-lying potential curves correlated with the metastable (5d(2))F-3(J) states.