On the Performance of QTP Functionals Applied to Second-Order Response Properties II: Dynamic Polarizability and...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• The first paper in this series evaluated Quantum Theory Project (QTP) functionals for static second-order response properties.
• This study extends the evaluation to frequency-dependent properties, crucial for understanding molecular interactions and spectroscopy.

Purpose of the Study:

• To assess the performance of 25 exchange-correlation (XC) functionals, including QTP functionals, for dynamic polarizabilities and C6 dispersion coefficients.
• To compare Kohn-Sham calculations with high-level methods like Coupled Cluster (CC3) and Equation of Motion Coupled Cluster with Singles and Doubles (EOM-CCSD).

Main Methods:

• Dynamic polarizabilities were computed at five different wavelengths using 25 XC functionals, alongside HF, LR-CC3, and EOM-CCSD methods.
• C6 dispersion coefficients were calculated using the Casimir-Polder equation.
• The performance of functionals was benchmarked against established theoretical methods.

Main Results:

• EOM-CCSD results closely matched LR-CC3 for dynamic polarizabilities, except at high frequencies.
• TPSS0 and QTP01 demonstrated the best performance among Kohn-Sham calculations for dynamic polarizabilities.
• O3LYP yielded the best results for C6 dispersion coefficients, with several other functionals showing comparable accuracy. QTP01 and LC-QTP were the top QTP functionals for C6 coefficients.

Conclusions:

• QTP functionals show promise for calculating frequency-dependent properties, with specific functionals excelling in different areas.
• The study provides valuable insights into the accuracy of various XC functionals for dynamic polarizabilities and C6 dispersion coefficients, aiding in the selection of appropriate methods for future research.