First-principles molecular dynamics simulations of condensed-phase V-type nerve agent reaction pathways and energy barriers

Computational studies of condensed-phase chemical reactions are challenging in part because of complexities in understanding the effects of the solvent environment on the reacting chemical species. Such studies are further complicated due to the demanding computational resources required to implement high-level ab initio quantum chemical methods when considering the solvent explicitly. Here, we use first-principles molecular dynamics simulations to examine condensed-phase decontamination reactions of V-type nerve agents in an explicit aqueous solvent. Our results include a detailed study of hydrolysis, base-hydrolysis, and nucleophilic oxidation of both VX and R-VX, as well as their protonated counterparts (i.e., VXH+ and R-VXH+). The decontamination mechanisms and chemical reaction energy barriers, as determined from our simulations, are found to be in good agreement with experiment. The results demonstrate the applicability of using such simulations to assist in understanding new decontamination technologies or other applications that require computational screening of condensed-phase chemical reaction mechanisms.