Representing molecules as atomic-scale electrical circuits with fluctuating-charge models

This document describes fluctuating charge models that represent molecules as electrical circuits with atomic charges that fluctuate. It introduces the QTPIE model, which improves upon previous models like QEq by including an overlap integral that introduces an explicit notion of distance, allowing it to better describe charge transfer and polarization. The QTPIE model is shown to predict correct dissociation behavior and charge distributions compared to ab initio results.