First-principles string molecular dynamics: An efficient approach for finding chemical reaction pathways

An efficient implementation of the string method within first-principles molecular dynamics (FPMD) was investigated. This string method was used to determine minimum energy pathways (MEP) connecting two metastable states of a system. A MEP is a path of minimum local energy that connects reactant and product states in configuration space. The adsorption of H ₂ on the Si(100) surface was used for analyzing the effectiveness of FPSMD in finding MEPs on a potential energy surface of density functional theory (DFT) quality. The results show that the chemical bond rearrangements that take place in a reaction can be monitored by studying the evolution of the MLWFs along a MEP.