Ab initio molecular dynamics: Theory and Implementation

2500Number200015001000CP PRL 1985AIMD50001970 1980 1990 2000Year nFigure 1. Publication and citation analysis. Squares: number of publications which appearedup to the year n that contain the keyword “ab initio molecular dynamics” (or synonyma suchas “first principles MD”, “Car–Parrinello simulations” etc.) in title, abstract or keyword list.Circles: number of publications which appeared up to the year n that cite the 1985 paper byCar and Parrinello 108 (including misspellings of the bibliographic reference). Self–citations andself–papers are excluded, i.e. citations of Ref. 108 in their own papers and papers coauthored byR. Car and / or M. Parrinello are not considered in the respective statistics. The analysis is basedon the CAPLUS (“Chemical Abstracts Plus”), INSPEC (“Physics Abstracts”), and SCI (“ScienceCitation Index”) data bases at STN International. Updated statistics from Ref. 405 .standard molecular dynamics. Another appealing feature of standard moleculardynamics is less evident, namely the “experimental aspect of playing with the potential”.Thus, tracing back the properties of a given system to a simple physicalpicture or mechanism is much harder in ab initio molecular dynamics. The brightside is that new phenomena, which were not forseen before starting the simulation,can simply happen if necessary. This gives ab initio molecular dynamics a trulypredictive power.Ab initio molecular dynamics can also be viewed from another corner, namelyfrom the field of classical trajectory calculations 649,541 . In this approach, whichhas its origin in gas phase molecular dynamics, a global potential energy surfaceis constructed in a first step either empirically or based on electronic structurecalculations. In a second step, the dynamical evolution of the nuclei is generatedby using classical mechanics, quantum mechanics or semi / quasiclassical approximationsof various sorts. In the case of using classical mechanics to describe thedynamics – the focus of the present overview – the limiting step for large systems is3