AB-INITIO MOLECULAR-DYNAMICS SIMULATIONS

Over the past decade, new simulation methodologies, such as the Car-Pa rrinello nb initio molecular dynamics technique, have become increasin gly important as tools to study and characterize condensed phase molec ular systems. We emphasize the versatility of these new approaches to simulation by reviewing selected applications to molecular crystals, l iquids, and clusters, which highlight a range of interesting phenomena . The molecular crystals white phosphorus, nitromethane, and hydrogen chloride dihydrate exhibit molecular reorientation phenomena, methyl t orsional motion, and proton-hopping events, respectively. We indicate how, in the latter examples, it is now possible to include quantum eff ects in the simulation of the proton motion. Ionic solvation and proto n transport in water are used to illustrate the current status of simu lations of liquid systems. The final topic in our survey deals with th e possibility of including the quantum nature of nuclear motions into the simulation methodology of clusters.