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Updated: Jul 12, 2025

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Economical Models for Electron Densities
Ellena K G Black1, Peter M W Gill1
1School of Chemistry, University of Sydney, Camperdown, NSW 2006, Australia.
Abstract:
We discuss a new theoretical framework for modeling molecular electron densities. Our approach decomposes the total density into contributions from basis function products and then approximates each product using constrained least-squares approximation in a tailored local basis of functions with adjustable non-linear parameters. We show how to solve directly for the expansion coefficients and Lagrange multipliers and present an iterative method to optimize the non-linear parameters. Example products from the Dunning cc-pVTZ basis set are discussed.
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