Improved supermolecular second order Møller-Plesset intermolecular interaction energies using time-dependent density...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Accurate calculation of intermolecular interaction energies is crucial for understanding molecular systems.
• Standard methods like Moller-Plesset perturbation theory (MP2) have limitations in describing dispersion interactions.

Purpose of the Study:

• To improve the accuracy of supermolecular MP2 interaction energies by incorporating time-dependent density functional theory (TDDFT).
• To evaluate the performance of the proposed correction method for various molecular dimers.

Main Methods:

• Correcting the uncoupled second-order dispersion contribution in MP2 energies with coupled dispersion from TDDFT.
• Comparing the results with high-level coupled cluster singles doubles with perturbative triples [CCSD(T)] calculations.
• Investigating the influence of different exchange-correlation potentials on the accuracy of the interaction energies.

Main Results:

• The TDDFT-corrected MP2 interaction energies show significant improvement over conventional MP2, especially when compared to CCSD(T) benchmarks.
• The choice of exchange-correlation potential critically affects the accuracy, with exact exchange-only potentials sometimes outperforming hybrid potentials.
• The proposed method shows promise, drawing parallels to previous work using time-dependent Hartree-Fock dispersion corrections.

Conclusions:

• The combination of MP2 and TDDFT offers a robust approach for accurate intermolecular interaction energy calculations.
• Careful selection of the exchange-correlation functional is essential for optimal performance.
• This method provides a valuable alternative for studying weak molecular interactions.