Analytical First Derivatives of the SCF Energy for the Conductor-Like Polarizable Continuum Model With Non-Static...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Continuum solvation models are essential for simulating chemical processes in solution.
• Accurate calculation of molecular properties requires efficient methods for geometry optimization and Hessian calculations.
• Previous methods for creating van der Waals-type cavities in polarizable continuum models had limitations.

Purpose of the Study:

• To derive and implement analytical gradients for the Gaussian-switching (SwiG) Conductor-like Polarizable Continuum Model (CPCM).
• To incorporate general nuclear coordinate-dependent non-static radii for van der Waals-type cavities using the dynamic radii adjustment for continuum solvation (Draco) scheme.
• To enable efficient geometry optimization and reliable numerical Hessian calculations within this framework.

Main Methods:

• Derivation of analytical gradients for the SwiG-CPCM model.
• Implementation of the dynamic radii adjustment for continuum solvation (Draco) scheme for cavity definition.
• Validation through comparison of analytical and numerical gradients, and geometry optimizations on diverse chemical species.
• Testing potential energy surface continuity and computational efficiency.

Main Results:

• Successful derivation and implementation of analytical gradients for SwiG-CPCM with Draco.
• Validation confirmed accuracy by comparing analytical and numerical gradients.
• Efficient geometry optimizations were achieved for small organic molecules, metal-organic complexes, and highly charged species.
• The method demonstrated robustness, even with significant changes in atomic radii.

Conclusions:

• The developed analytical gradients for SwiG-CPCM with Draco provide an efficient and accurate method for computational chemistry.
• This approach facilitates reliable geometry optimizations and Hessian calculations, applicable across a wide range of chemical systems.
• The implementation in ORCA ensures broad accessibility and applicability for researchers.