Incorporating density functional potential in classical molecular dynamics simulation

UNDERSTANDING the properties of reactions in condensed phases, e.g. in solutions or in enzymes, is one of the most challenging questions to both physical chemists and biological chemists. Classical molecular mechanics potential, though widely tested and employed in molecular dynamics simulation, is not feasible to simulating the reaction process where the quantum effects are dominative. Several hybrid approaches have been proposed to combine quantum mechanics (QM) potential with molecular mechanics (MM) potential, in which the reaction site is treated quantum mechanically, and the environment classically.The substantial differences among those hybrid strategies are the QM models employed to treat reaction site, which includes empirical VB models, semi-empirical molecular orbital models (MNDO, AM1,PM3), Hartree-Fock models, etc. Recently, density functional (DF) theory has been tested as the quantum mechanics model in the hybrid method to treat the reaction site. As another "ab initial" theory,DF theory