Trihydrogen cation solvated by rare gas atoms: RgnH3+

Abstract

The triatomic hydrogen cation solvated by rare gases, RgnH3+, n=1–5, Rg=He, Ne, Ar, Kr, Xe, is investigated by density functional theory. The results indicate that while the first solvent atom distorts and destabilizes the H3+ center, the ion is restabilized by additional solvation. For the n=3 species, the symmetric D3h structure is the global minimum for all rare gases except Xe; the n=4,5 solvent atoms are placed on the C3 axis of the molecule. The computed potential energy surface of the isomerization reaction RgnH3+→H2Rg2H+Rgn−2, n=2–4, provides insight into the possible H3+ formation and destruction mechanisms in rare gas matrices. As expected, solid neon is the most suitable medium for H3+ studies, with its stabilization becoming progressively more difficult in the heavier rare gas solids.