Neutral and ionic dopants in helium clusters: interaction forces for the Li-2(a(3)Sigma(+)(u))-He and Li-2(+)(X-2 Sigma(+)(g))-He complexes

The potential energy surface (PES) describing the interactions between Li-2((1)Sigma(u)(+)) and He-4 and an extensive study of the energies and str uctures of a set of small clusters, Li-2(He)(n), were reported in a previous series of publications. In the present work, the same analysis is extended to the case of the excited Li-2(a(3)Sigma(u)(+)) and of the ionized Li-2(+) (X(2)Sigma(g)(+)) moiety. Calculated interaction potentials for the two title syst ems and the corresponding fitting of the computed points are shown. For both surfaces the MP4 method with cc-pV5Z basis sets has been used to generate an e xtensive range of radial/angular coordinates of the two-dimensional PESs which describe rigid rotor molecular dopants interacting with one He partner.