Non-additive effects in liquid water by parallel molecular dynamics simulation

In this work, the non-additive effects in liquid water have been studied with molecular simulation techniques. An intermolecular potential for water, MCYna, in which many-body induction and dispersion are incorporated with a pure pair potential, has been established. New parallel algorithms were designed in order to decompose the intensive computation load involved in many-body interaction and induction evaluation in the MCYna water model. The decomposition strategies are implemented with message passing interface (MPI). With the developed parallel molecular dynamics code, a wide spectrum of properties of water, such as energetics, structural properties and dielectric properties have been investigated. In comparison to pure pair model, the new model produced significantly improved properties, with most of the investigated properties in good agreement with the experiment. The observed improvement clarifies the important role of non-additive interactions in liquid water systems. The individual role of different types of non-additive interactions are studied with the induction having the strongest effects influence. Therefore the dominant role of induction over other non-additives in liquid water has been clarified. The results have also demonstrated that non-additive interactions are responsible for marked influences on solvation-related properties, such as hydrogen bonding, coordination and dielectric properties of liquid water systems. The improvement of water properties with non-additive interactions infers that the non-additive interaction has substantial effects in aqueous systems, where hydration is believed as the deterministic process.