Fully Polarizable Multiconfigurational Self-consistent Field/Fluctuating Charge Approach

TL;DR

This paper introduces a novel multiscale computational approach combining MCSCF and Fluctuating Charges to accurately model solvation effects and excitation energies in solution, validated through applications to formaldehyde and para-nitroaniline.

Contribution

It presents a fully polarizable multiconfigurational method coupling MCSCF with FQ force field, enabling dynamic solvation modeling and improved spectral predictions.

Findings

Accurately predicts excitation energies in aqueous solution.

Captures conformational and solvation dynamics effectively.

Shows improved agreement with experimental data.

Abstract

A multiscale model based on the coupling of the multiconfigurational self-consistent field (MCSCF) method and the classical atomistic polarizable Fluctuating Charges (FQ) force field is presented. The resulting MCSCF/FQ approach is validated by exploiting the CASSCF scheme through application to compute vertical excitation energies of formaldehyde and para-nitroaniline in aqueous solution. The procedure is integrated with molecular dynamics simulations to capture the solute's conformational changes and the dynamic aspects of solvation. Comparative analysis with alternative solvent models, gas-phase calculations, and experimental data provides insights into the model's accuracy in reproducing solute-solvent molecular interactions and spectral signals.