Atomistic Simulations of Activated Processes in Materials

Activated processes in materials are important for many of the properties that make them function. Batteries and catalysts are examples for which understanding how the component materials function on a timescale of milliseconds to seconds is critical to making improvements in a rational way. Modeling materials over these long timescales, relative to the timescale of atomic vibrations, is one of the grand challenges of the field. Transition state theory is central to bridging this timescale gap, and in the materials community, the harmonic approximation and the determination of saddle points to quantify reaction rates are ubiquitous. In this review, singleand doubleended methods for saddle point finding are discussed, as well as how finding saddle points can be used in the adaptive kinetic Monte Carlo method to model materials properties on the timescale of activated processes. Applications of surface diffusion and chemistry, phase boundary migration, and solid-solid phase transitions are presented. 199 Click here to view this article's online features: ANNUAL REVIEWS Further A nn u. R ev . M at er . R es . 2 01 7. 47 :1 99 -2 16 . D ow nl oa de d fro m w w w .a nn ua lre vi ew s.o rg A cc es s p ro vi de d by U ni ve rs ity o f T ex as A us tin o n 07 /0 9/ 17 . F or p er so na l u se o nl y. MR47CH10-Henkelman ARI 12 June 2017 11:37 MD: molecular dynamics PES: potential energy surface State: an associated set of points on the potential energy surface Minimum energy path: a path that follows the gradient from minima across saddle points; also termed an intrinsic reaction coordinate