London dispersion in density-functional theory and application to molecular crystal structure prediction
Erin Johnson
Professor and Herzberg-Becke Chair in Theoretical Chemistry
Department of Chemistry, Dalhousie University
Tuesday, April 2, 2024
2:30 p.m.
In-person: C2-361 (Reading Room)
Abstract: Inclusion of London dispersion in density-functional calculations is now standard practice in computational chemistry and materials science. In this talk, we review how the dispersion energy can be written as an asymptotic series expansion from perturbation theory, which can be added to the self-consistent energy. We will then focus on the exchange-hole dipole moment (XDM) model, in which the dispersion coefficients are non-empirical and depend directly on the electron density and related properties. XDM offers simultaneous high accuracy for a diverse range of chemical systems, including molecular crystals, layered materials, and metal surfaces. Application to the problem of molecular crystal structure prediction will be highlighted, where accurate and efficient computation of relative polymorph energies is of central importance.