Title: Large scale approximate quantum models for materials, molecules and interfaces

Abstract: In this seminar I will review some of the recent developments in density-functional derived semi-empirical models for large size or long time-scale modelling of systems where electronic structure is important. These methods are 2 – 3 orders of magnitude faster than the common choice of density functional theory, but are capable of capturing reactive chemistry or complex electronic states which are challenging to describe with classical potentials. Similarly, unlike many machine learning based models, these methods use approximate but physically derived descriptions of interactions, constraining the results of the model. Focussing on the DFTB+ code (https://dftbplus.org/), some of the recent and near term developments in this area will be discussed on the build-up to the next methods paper to follow on from [1] in about 2 years time.

I will also briefly talk about some of the longer term multi-physics extensions of the code, for example for correlated electronic systems or high performance Maxwell solvers [2].

1. B. Hourahine et al., “DFTB+, a software package for efficient approximate density functional theory based atomistic simulations” J. Chem. Phys. 2020; 152, 124101. https://doi.org/10.1063/1.5143190

2. F. Papoff and B. Hourahine, "Geometrical Mie theory for resonances in nanoparticles of any shape," Opt. Express 2011; 19, 21432. https://doi.org/10.1364/OE.19.021432

Bio: I started the DFTB+ project (https://www.dftbplus.org) in 2004 to develop a modern implementation of the semi-empirical density functional based tight binding method. See B. Hourahine et al., J. Chem. Phys. 2020; 152, 124101. https://doi.org/10.1063/1.5143190 for an overview of recent features. I have also developed new methods for accurate electromagnetic and plasmonic calculations, plus tools for modelling kinetic processes in crystal growth and annealing.

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