An Atomic Counterpoise Method for Estimating Inter- and Intramolecular Basis Set Superposition Errors.

Area of Science:

• Computational Chemistry
• Quantum Chemistry

Background:

• Basis set superposition error (BSSE) is a significant artifact in computational chemistry.
• Accurate BSSE estimation is crucial for reliable molecular property predictions.

Purpose of the Study:

• To introduce and validate a novel atomic counterpoise (ACP) method for BSSE calculation.
• To assess the applicability of the ACP method for both inter- and intramolecular BSSE.

Main Methods:

• The proposed atomic counterpoise method decomposes BSSE into atomic contributions.
• The method is applicable to both independent particle and electron correlation models.
• Calculations were performed at Hartree-Fock (HF) and Møller-Plesset perturbation theory (MP2) levels.

Main Results:

• The ACP method yields results comparable to the established molecular counterpoise (MCP) method for intermolecular BSSE.
• The ACP method effectively estimates intramolecular BSSE, a challenging area for existing methods.
• Computational cost is manageable, typically doubling the time for uncorrected energy calculations.

Conclusions:

• The atomic counterpoise method offers a robust and efficient approach for BSSE correction.
• Its ability to handle intramolecular BSSE makes it a valuable tool in computational chemistry.
• The ACP method enhances the accuracy of theoretical molecular calculations.