Potential energy curves and dipole transition moments for electronic states of ArHe and HeNe

Relativistic core-potential calculations have been carried out on the groun d and excited Omega states of ArHe and HeNe correlating with the atomic lim its Ar*(3p(5)4s, P-3,P-1) and Ne*(2p(5)3s, P-3, P-1), respectively, and wit h ground-state He atoms. The potential energy curves of the excited states of ArHe are repulsive. The potential energy curves of the 0(-)(I), 1(I) and 0(+)(II)2p sigma --> 3s states of HeNe show a local Rydberg minimum at 2.8 bohr and a barrier at 4.0 bohr, while the other excited state potentials o f HeNe are repulsive. For both ArHe and HeNe, large dipole transition momen ts are calculated connecting the ground state with states dissociating to a tomic limits from which radiative transitions to the atomic ground state ar e allowed. Small but nonzero dipole transition moments are obtained for sho rt internuclear distances for the transitions from the 1(I) state, which co rrelates with the metastable P-3(2) state of Ar (in ArHe) or Ne (in HeNe). The radiative lifetime of the 1(I) state of HeNe (estimated from the vertic al transition at 2.8 bohr) is 18 mus. (C) 2001 American Institute of Physic s.