Ab initio study of interaction-induced NMR shielding constants in mixed rare gas dimers

The interaction-induced contribution to the NMR shielding constants in homonuclear A(2) and heteronuclear AB (A,B=He,Ne,Ar) dimers is obtained ab initio by employing a coupled cluster singles and doubles with perturbative treatment of triples wave function model and extended correlation-consistent basis sets. The second virial coefficients entering the expansion of the property with the density are then computed in a fully quantum mechanical approach, for temperatures ranging from the limit of dissociation of the dimer to well above standard conditions. The results can be used to describe the density and temperature dependence of the shielding constants in binary mixtures of helium, neon, and argon. The predicted effects should be observable for the interaction of Ne-21 with other rare gases. (c) 2007 American Institute of Physics.