Quadratic integrand double-hybrid made spin-component-scaled.

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Density Functional Theory

Background:

• Double-hybrid density functionals (DHDFs) are crucial for accurate chemical predictions.
• Spin-component scaling (SCS) and spin-opposite scaling (SOS) are established methods to improve DHDFs.
• The nonempirical quadratic integrand double-hybrid (QIDH) model provides a robust framework for evaluating DHDFs.

Purpose of the Study:

• To propose and validate analytical expressions for SCS and SOS schemes in DHDFs.
• To assess the performance of these schemes within the QIDH model.
• To identify computationally efficient alternatives for accurate electronic structure calculations.

Main Methods:

• Development of two analytical expressions for SCS and SOS schemes.
• Extensive testing using the QIDH model.
• Evaluation on energetic properties from the GMTKN30 benchmark database.
• Assessment of structural properties for organic compounds.

Main Results:

• The proposed analytical expressions effectively rationalize SCS and SOS schemes.
• The SOS variant achieves accuracy comparable to the original QIDH model.
• The SOS approach demonstrates reduced computational demand.
• Accurate predictions for energetic and structural properties were obtained.

Conclusions:

• The SOS scheme offers a computationally efficient and accurate alternative for DHDFs.
• The developed analytical expressions enhance the theoretical foundation of SCS and SOS methods.
• This work provides a valuable tool for computational chemists seeking high accuracy with lower computational cost.