Computational study of the dissolution of some atomic and diatomic species in the square and hexagonal 2-D helium lattices

Abstract

Dissolution of some industrially relevant atomic and diatomic species (Ar, Ne, H, O, H2, N2 and O2) in the 5 x 5 2-D hexagonal and square helium lattices, as the model of the liquid helium cryogen, has been studied using ab initio MP2/6-31++G computations. Structural, electronic and thermochemical properties have been calculated and analyzed for these solution lattices. Results of these calculations show that dissolution of Ar, Ne, H and H2 species is more favored at higher temperatures. A reverse trend is observed for the dissolution of O, N2 and O 2 species. Astaggered orientation is preferred by all diatomic species in both lattices. Results of this study also show that breakage of the O2 molecule becomes slightly easier in the 2-D helium lattices as compared with that of the H2 molecule. Effect of the cavity geometry and size, and position of the solute in the lattice have also been studied. Analysis of the results shows that the range of the interaction between the solute and solvent atoms is only one helium layer.