ZMP-SAPT: DFT-SAPT using ab initio densities.

Area of Science:

• * Quantum chemistry
• * Computational chemistry
• * Theoretical chemistry

Background:

• * Symmetry Adapted Perturbation Theory (SAPT) is crucial for analyzing intermolecular interactions.
• * Density Functional Theory (DFT)-SAPT methods face challenges due to arbitrary exchange-correlation potentials and kernels.
• * Accurate calculation of monomer properties is essential for reliable SAPT results.

Purpose of the Study:

• * To develop a novel approach, ZMP-SAPT, that reduces the dependence of DFT-SAPT on DFT exchange-correlation models.
• * To enable the computation of monomers at the high-accuracy coupled-cluster level within the SAPT framework.
• * To provide a more robust method for calculating intermolecular interaction energies.

Main Methods:

• * Employing ab initio Brueckner Doubles densities for monomer calculations.
• * Constructing Kohn-Sham orbitals using the Zhao-Morrison-Parr (ZMP) method.
• * Applying SAPT to determine intermolecular interaction energies using ZMP-derived monomer properties.

Main Results:

• * The ZMP-SAPT approach successfully mitigates the first-order dependence on DFT exchange-correlation potential models.
• * Calculations were performed on small dimer systems including rare gas atoms, cations, and anions.
• * ZMP-SAPT results demonstrated good agreement with established methods like the Tang-Toennies model and coupled cluster calculations.

Conclusions:

• * The ZMP-SAPT method offers a significant improvement over standard DFT-SAPT by incorporating high-level ab initio monomer data.
• * This approach enhances the reliability and accuracy of intermolecular interaction energy predictions.
• * ZMP-SAPT provides a valuable tool for studying interactions in diverse chemical systems.