Theoretical and Computational Chemistry

Are GAPT Charges Really Charges?



GAPT has turned into a very popular charge model since it was proposed three decades ago. During this period, several works aiming to compare different partition schemes have included it among their tested models. Nonetheless, GAPT exhibits a set of unique features that prevent it from being directly comparable to "standard" partition schemes. We take this opportunity the explore some of these features, mainly related to the need of evaluating multiple geometries and the dynamic character of GAPT, and show how to obtain the static and dynamic parts of GAPT from any static charge model in the literature. We also present a conceptual evaluation of charge models that aims to explain, at least partially, why GAPT and QTAIM charges are strongly correlated to one another, even though they seem to be constructed under very different frameworks. Not only are they the sole models whose definitions admit direct comparison between theoretical and experimental values, both are deeply ingrained with the response of the electronic density to nuclear displacements.

Version notes

v1, submitted for publication.


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