Equation of Motion for the Solvent Polarization Apparent Charges in the Polarizable Continuum Model: Application to Time-Dependent CI

TL;DR

This paper extends the equations of motion for solvent polarization charges within the Polarizable Continuum Model to a Time-Dependent Configuration Interaction framework, enabling more accurate real-time simulation of electron dynamics in solvated molecules.

Contribution

The authors develop an EOM-PCM approach coupled with TD CI, overcoming limitations of RT TDDFT and enabling better simulation of solvent effects on electron dynamics.

Findings

Successfully modeled solvent Debye relaxation after electronic excitation.

Compared EOM-PCM results with Onsager model, showing qualitative agreement.

Demonstrated the approach's potential for studying electron dynamics in solution.

Abstract

The dynamics of the electrons for a molecule in solution is coupled to the dynamics of its polarizable environment, i.e., the solvent. To theoretically investigate such electronic dynamics, we have recently developed equations of motion (EOM) for the apparent solvent polarization charges that generate the reaction field in the Polarizable Continuum Model (PCM) for solvation and we have coupled them to a real-time time-dependent density functional theory (RT TDDFT) description of the solute [Corni et al. J. Phys. Chem. A 119, 5405 (2014)]. Here we present an extension of the EOM-PCM approach to a Time-Dependent Configuration Interaction (TD CI) description of the solute dynamics, which is free from the qualitative artifacts of RT TDDFT in the adiabatic approximation. As tests of the developed approach, we investigate the solvent Debye relaxation after an electronic excitation of the solute obtained either by a $\pi$ pulse of light or by assuming the idealized sudden promotion to the excited state. Moreover, we present EOM for the Onsager solvation model and we compare the results with PCM. The developed approach provides qualitatively correct real-time evolutions and is promising as a general tool to investigate the electron dynamics elicited by external electromagnetic fields for molecules in solution.