A three-dimensional He-CO potential energy surface with improved long-range behavior

A weakness of the "CBS + corr" He-CO potential energy surface (Peterson and McBane, 2005) has been rectified by constraining the potential to adopt accurate long-range behavior for He-CO distances well beyond 15a(0). The resulting surface is very similar to the original in the main part of the interaction. Comparison with accurately known bound-state energies indicates that the surface is slightly improved in the region sampled by the highest lying bound states. The positions of shape and Feshbach resonances within a few cm(-1) of the j = 1 excitation threshold are essentially unchanged. The low-energy scattering lengths changed noticeably. The revised surface generates a small negative limiting scattering length for collisions with H-4(e), while the original surface gave a small positive one. Both surfaces yield scattering lengths quite different from the widely used surface of Heijmen et al. (1997) for both He isotopes. (C) 2016 The Author. Published by Elsevier Inc.