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

Area of Science:

• Computational chemistry
• Quantum chemistry
• Spectroscopy

Background:

• Accurate calculation of molecular absorption spectra is crucial for understanding electronic structure.
• Time-dependent density functional theory (TDDFT) with the complex polarizability algorithm is a common method for spectral calculations.
• The accuracy of TDDFT calculations is sensitive to the choice of auxiliary basis sets.

Purpose of the Study:

• To develop and optimize new auxiliary basis sets for fitting induced electron density.
• To improve the accuracy and efficiency of absorption spectra calculations using TDDFT.
• To create transferable and compact basis sets for broader applicability.

Main Methods:

• Optimization of auxiliary basis functions to fit induced electron density.
• Utilizing the complex polarizability algorithm within TDDFT.
• Development of an automatic procedure with descriptors to assess spectral resemblance to a reference.
• Testing basis set transferability across different molecules for each element.

Main Results:

• A new set of auxiliary basis functions has been optimized for accurate absorption spectra.
• The new basis sets are significantly smaller and more accurate than previous ones.
• The developed basis sets demonstrate good transferability to molecules outside the initial training set.
• These optimized basis sets have been incorporated into the AMS suite of programs.

Conclusions:

• The new auxiliary basis sets significantly enhance the accuracy and reduce the computational cost of TDDFT-based absorption spectra calculations.
• The improved basis sets expand the applicability of the polarizability TDDFT (polTDDFT) method.
• This work provides a more efficient and accurate computational tool for electronic structure studies.