Effects of micro-hydration in proton transfer from H2S·NO+ complex to water: Ab initio and molecular dynamics study

Abstract

We have studied several microhydrated (H2O)n·NO+·H2S structures (n = 1–3) and their fragments using wave-function based approach (coupled-clusters including single, double and non-iterative triple substitutions – CCSD(T) and second-order perturbation theory – MP2) and also employing density functional theory (with BLYP and ωB97XD functional). MP2 energetics is very close to CCSD(T) one. Both functionals provide reasonable binding energies compared to MP2, the ωB97XD being superior to BLYP. The exploratory ab initio molecular dynamics performed on four- and five-body clusters revealed that the hydrogen bonds network and cooperativity in these systems play a crucial role in the proton transfer from H2S·NO+ to H2O and its conversion to thionitrous acid.