Optimization of density fitting auxiliary Slater-type basis functions for time-dependent density functional theory

A new set of auxiliary basis function suitable to fit the induced electron density is presented. Such set has been optimized in order to furnish accurate absorption spectra using the complex polarizability algorithm of time-dependent density functional theory (TDDFT). An automatic procedure has been set up, able, thanks to the definition of suitable descriptors, to evaluate the resemblance of the auxiliary basis-dependent calculated spectra with respect to a reference. In this way, it has been possible to reduce the size of the basis set maximizing the basis set accuracy. Thanks to the choice to employ a collection of molecules for each element, such basis has proven transferable to molecules outside the collection. The final sets are therefore much more accurate and smaller than the previously optimized ones and have been already included in the database of the last release of the AMS suite of programs. The availability of the present new set will allow to improve drastically the applicability range of the polTDDFT method with higher accuracy and less computational effort.

Automated summary

This article presents a new set of auxiliary basis functions suitable for fitting the induced electron density. The set has been optimized to accurately calculate absorption spectra using the complex polarizability algorithm of time-dependent density functional theory (TDDFT). An automatic procedure has been developed to evaluate the resemblance of the calculated spectra to a reference, allowing for the reduction of the basis set size while maximizing accuracy. This new set of basis functions has already been included in the latest release of the AMS suite of programs, and will greatly improve the applicability range of the polTDDFT method with higher accuracy and less computational effort.