A short-range gradient-corrected density functional in long-range coupled-cluster calculations for rare gas dimers

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Current density functionals struggle with accurately describing long-range van der Waals interactions.
• Wavefunction-based ab initio methods provide accurate correlation but are computationally expensive.

Purpose of the Study:

• To improve the accuracy of computational chemistry methods for van der Waals interactions.
• To develop a hybrid approach combining short-range density functionals and long-range ab initio methods.

Main Methods:

• Developed a new gradient-corrected short-range functional based on the Perdew-Burke-Ernzerhof (PBE) functional.
• Incorporated coupled-cluster (CC) methods, including CCSD and CCSD(T), for the long-range ab initio component.

Main Results:

• The hybrid approach significantly improves the treatment of van der Waals interactions.
• The inclusion of long-range ab initio correlation addresses deficiencies in standard density functionals.
• The method exhibits reduced basis set dependence compared to full ab initio calculations.

Conclusions:

• The proposed scheme offers a more accurate and efficient way to model systems with significant van der Waals contributions.
• The enhanced method achieves higher accuracy than traditional ab initio methods for triple-zeta basis sets.