The same number of optimized parameters scheme for determining intermolecular interaction energies

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• Basis set superposition errors (BSSE) affect intermolecular interaction energy calculations.
• The counterpoise method is a common but imperfect approach to correct for BSSE.

Purpose of the Study:

• To introduce and evaluate the Same Number Of Optimized Parameters (SNOOP) scheme.
• To provide an alternative to the counterpoise method for BSSE correction.
• To ensure a balanced quality between monomer and dimer basis set calculations.

Main Methods:

• Theoretical and numerical comparison of SNOOP, uncorrected, and counterpoise schemes.
• Application to second-order Møller-Plesset perturbation theory (MP2) and coupled-cluster with single, double, and approximate triple excitations (CCSD(T)) methods.
• Evaluation of interaction energies using finite basis sets.

Main Results:

• The SNOOP scheme generally outperforms uncorrected and counterpoise methods.
• SNOOP interaction energies are comparable to basis set extrapolated counterpoise-corrected results at similar computational cost.
• SNOOP ensures a balanced quality in finite basis set calculations for interacting systems.

Conclusions:

• The SNOOP scheme is a promising alternative for treating BSSE in intermolecular interaction energy calculations.
• SNOOP offers improved accuracy and comparable efficiency to existing methods.
• This method enhances the reliability of quantum chemical predictions for molecular interactions.