Evaluating fast methods for static polarizabilities on extended conjugated oligomers

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Accurate polarizability calculations are vital for diverse chemical applications.
• Efficient methods are needed for large molecular systems and sets of molecules.

Purpose of the Study:

• To benchmark calculation methods for polarizable materials.
• To assess the accuracy of the GFN2/D4 additive model and DFT methods.
• To identify efficient and accurate approaches for polarizability calculations.

Main Methods:

• Investigated the accuracy of the GFN2 semi-empirical method with the D4 dispersion model.
• Compared additive polarizabilities to ωB97XD results using PubChemQC and a benchmark set.
• Evaluated DFT polarizability calculations with varying basis sets and augmentation levels.

Main Results:

• Additive GFN2/D4 polarizabilities showed significant errors for large conjugated oligomers.
• An empirical quadratic correction largely remedied the errors in GFN2/D4 polarizability calculations.
• Non-augmented DFT basis sets, with a linear correction, achieved accuracy comparable to aug-cc-pVTZ for large, polarizable species.

Conclusions:

• Empirical corrections can significantly improve the accuracy of GFN2/D4 polarizability calculations.
• Cost-effective DFT approaches using non-augmented basis sets are viable for large, highly polarizable systems.
• This research provides guidance for selecting efficient and accurate polarizability calculation methods.