Fitted models for intermolecular interactions from first principles
Date
2020
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
Modern electronic structure methods are able to describe molecular systems
accurately enough to predict most observed phenomena. Unfortunately, the compu-
tational cost of such methods becomes prohibitively high as the size of the system
grows. This problem can be alleviated by the use of relatively simple models which
are fitted to data from high-level calculations. By maintaining the predictive accuracy
of methods based on first principles at a computational cost which is many orders of
magnitude smaller, these intermolecular potential energy surfaces (PESs) provide an
important bridge to many applications in chemistry and materials science. Despite
their importance and widespread use, these PESs are typically constructed in an ad
hoc manner. The focus of this work is to generalize and improve upon existing method-
ology for the generation of intermolecular PESs. These advancements are consolidated
into a software package called autoPES, which is designed to be sufficiently automated
that it is accessible to researchers with only a basic understanding of the underlying
theory. The validity of this approach is demonstrated by applying it to predict the
crystal structures of various organic molecules, and to compute accurate vibrational
energies of the water, methane, and water-methane dimers. Finally, we extend the PES
generation methodology to handle the difficult case where the monomers are allowed
to deform substantially from their gas phase geometries.
Description
Keywords
Crystal, Intermolecular, Potential