Damped Linear Response TDDFT with Range-Separated Functionals and Density Fitting

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Quantum Chemistry

Background:

• Time-dependent density functional theory (TDDFT) is crucial for simulating molecular electronic excited states.
• Range-separated (RS) exchange-correlation (xc-) functionals offer improved accuracy but can be computationally expensive.
• Efficient methods are needed to apply advanced functionals to larger systems.

Purpose of the Study:

• To enhance the computational efficiency of RS-xc functionals within TDDFT.
• To implement the Resolution of the Identity (RI) technique for TDDFT calculations.
• To validate the accuracy and efficiency of the RI-implemented method for photoabsorption spectra prediction.

Main Methods:

• Employed the Resolution of the Identity (RI) technique to approximate integrals.
• Integrated RI into the polTDDFT algorithm, a complex damped polarization method.
• Utilized the Hybrid Diagonal Approximation for RS-xc functionals.
• Implemented within the AMS/ADF program suite.

Main Results:

• Demonstrated excellent accuracy and computational efficiency compared to the Casida algorithm.
• Validated on a model ethylene-tetrafluoroethylene charge-transfer system.
• Successfully reproduced the experimental photoabsorption spectrum of a large donor-acceptor-acceptor triad.

Conclusions:

• The RI-based TDDFT method provides a reliable and computationally efficient tool for predicting photoabsorption spectra.
• The method accurately captures charge-transfer transitions.
• Suitable for applications to large molecular systems up to several hundred atoms.