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 theor etically. Born-Oppenheimer potential curves are calculated with a comb ination of semiempirical model potentials and pseudopotentials to repr esent the interactions between the valence electrons of the barium ato m and the closed-shell cores. The molecular basis set is constructed f rom numerical eigenstates of the Ba+ ion. Spin-orbit coupling is inclu ded explicitly in the e(-)-Ba2+ interaction Hamiltonian. We report hig her-lying potential curves correlated with the metastable (5d(2))F-3(J ) states.