Nonequilibrium Solvent Polarization Effects in Real-Time Electronic Dynamics of Solute Molecules Subject to Time-Dependent Electric Fields: A New Feature of the Polarizable Continuum Model

Abstract

We develop an extension of the time-dependent equation-of-motion formulation of the polarizable continuum model (EOM-TDPCM) to introduce nonequilibrium cavity field effects in quantum mechanical calculations of solvated molecules subject to time-dependent electric fields. This method has been implemented in Octopus, a state-of-the-art code for real-space, real-time time-dependent density functional theory (RT-TDDFT) calculations. To show the potential of our methodology, we perform EOM-TDPCM/RT-TDDFT calculations of trans-azobenzene in water and in other model solvents with shorter relaxation times. Our results for the optical absorption spectrum of trans-azobenzene show (i) that cavity field effects have a clear impact in the overall spectral shape and (ii) that an accurate description of the solute shape (as the one provided within PCM) is key to correctly account for cavity field effects.

Dielectric continuum methods for quantum chemistry

“…When such a model is used in the context of continuum solvation theory, the polarization charge becomes explicitly time‐dependent and the permittivity for “fast” polarization is the real part of ε ( ω ) for frequencies larger than the perturbation of interest. Such models have been used to simulate the time‐dependent Stokes shift in the fluorescence energy, 527–529 and to simulate the combined response of the molecule and the medium to an external field that is resonant with an excited state of the solute 531,533 . The latter application makes the most sense when combined with electronic structure methods that simulate time‐dependent electron dynamics, 534,535 but these explicitly time‐dependent approaches are not considered in this work.…”

“…Such models have been used to simulate the time-dependent Stokes shift in the fluorescence energy, [527][528][529] and to simulate the combined response of the molecule and the medium to an external field that is resonant with an excited state of the solute. 531,533 The latter application makes the most sense when combined with electronic structure methods that simulate time-dependent electron dynamics, 534,535 but these explicitly timedependent approaches are not considered in this work.…”

Quantum and semiclassical dynamical studies of nonadiabatic processes in solution: achievements and perspectives

“…In this respect some interesting methodological developments have been recently proposed, allowing a time-dependent extension of PCM. [128][129][130][131][132][133] They exploit the Debye dielectric model, 134 where the solvent is characterized by a complex dielectric function allowing to interpolate between the static and the dynamic dielectric constants. The authors of ref.…”

Quantum optimal control theory for solvated systems

“…is therefore the field that can be directly controlled by shaping the incident laser pulse. The q cf [ε M (t)] are given by a PCM-like equation: [35,40,45]…”