Ionized and in aqueous environment: Ab initio QMCF-MD studies

Ab initio quantum mechanical charge field molecular dynamics (QMCF-MD) simulations were performed for CO 2 + and SO 2 + in water at the restricted open-shell Hartree–Fock (ROHF) level of theory employing Dunning DZP basis sets for solute and solvent molecules. Simulation data of these hydrated ionic species were compared to their corresponding neutral precursors, CO 2 and SO 2 illustrating contrasting structures and dynamical behavior. Hydrated CO 2 + is subject to weaker hydration than CO 2 whereas SO 2 + associates with water molecules via stronger H-bonds than SO 2 , CO 2 + and CO 2 molecules. Ionization of both gases also leads to a different relative influence on the hydration behavior in aqueous environment reflected by C O wat and S O wat mean distances of ∼3.1 Å and ∼2.7 Å in hydrated CO 2 + and SO 2 + , respectively. In a cloudy atmosphere hydrated CO 2 + and SO 2 + can produce other oxidized species, which are thought to be partly implicated in earth’s temperature activity.