London Dispersion in Density-Functional Theory and Application to Molecular Crystal Structure Prediction

Abstract: Density-functional theory (DFT) methods are the workhorse of modern computational chemistry. However, conventional functionals do not include the physics of London dispersion, which is necessary to model intermolecular interactions. One approach to modeling dispersion is 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.

A short bio: Erin R. Johnson is originally from Ottawa, Canada and obtained her B.Sc. (Honours) at Carleton University. She completed her Ph.D. in chemistry at Queen's University in 2007, under the supervision of Prof. Axel Becke. She was then an NSERC post-doctoral fellow at Duke University in the group of Prof. Weitao Yang. Johnson is now a Professor at Dalhousie University, in Halifax, Canada, where she holds the Herzberg-Becke Chair in Theoretical Chemistry. Her research focuses on development and application of density-functional theory, with an emphasis on intermolecular interactions and molecular crystals. She has received numerous prestigious awards, including the 2021 Steacie Prize, the 2020 Rutherford Memorial Medal in Chemistry, a 2019 E.W.R. Steacie Memorial Fellowship, and the 2018 Dirac Medal. She is currently spending her sabbatical at the University of Cambridge, where she is a Royal Society Wolfson Visiting Fellow.