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

Abstract

Within this work, we present the derivation and implementation of analytical gradients for the Gaussian-switching (SwiG) Conductor-like Polarizable Continuum Model (CPCM) with general nuclear coordinate-dependent non-static radii used for the creation of van der Waals-type cavities. This is done using the recently presented dynamic radii adjustment for continuum solvation (Draco) scheme. This allows for efficient geometry optimization and reasonable numerical Hessian calculations. The derived gradient is implemented in ORCA, and therefore is easily applicable. The derivation and implementation is validated by comparing analytical and numerical gradients and testing geometry optimizations on a diverse test set, including small organic compounds, metal-organic complexes, and highly charged species. We additionally test the continuity of the potential energy surface using an example where very strong changes in the radii occur. The computational efficiency of the derived gradient is investigated.