Molecular Response Method for Solvated Molecules in Nonequilibrium Solvation

Abstract

We present an extension of the molecular response method of solvated compounds. The extension treats in a proper fashion the effects of nonequilibrium solvation on the molecular properties of the solvated compound. The molecular properties evaluated within the response formalism are properties that are measured using high-frequency electromagnetic fields. We consider the changes in the molecular properties due to nonequilibrium solvation. The nonequilibrium solvation arises from changes in the molecular charge distribution induced by the high-frequency perturbation. The optical polarization vector is at all times assumed to be in equilibrium with the charge distribution of the solute, contrary to the inertial polarization, which is not necessarily in equilibrium with the charge distribution of the solute. We calculate shifts of excitation energies and frequency-dependent polarizabilities as a function of the optical and static dielectric constants.

Analytical Hartree–Fock calculation of the dynamical polarizabilities α, β, and γ of molecules in solution

“…With respect to other existing methods based on the use of continuous model, [1][2][3][4][5][6][7] this method is characterized by an higher level of generality.…”

The iterative self‐consistent reaction‐field method: The refractive index of pure water

“…The microscopic model that we use is the nonequilibrium, linear response SCRF model [24]. The cavity shape is spherical with radius, R cav , which reduces the number of arbitrary cavity parameters to a minimum, and the charge distribution of the solute molecule is represented in terms of a multipole expansion.…”

“…Paramount to the latter is the electric representation of the solute charge distribution along with the underlying quantum mechanical method used to derive this. Hence, multipole expansion of the solute charge distribution to orders beyond dipole terms is necessary [15,19,27,29,37,38], as is the use of correlated methods [13,20,21,24,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55].…”

“…Refinements in the representation of the surrounding medium have focused mainly on aspects such as the cavity geometry, radial dependence of the dielectric constant, and effects of inertial polarization [21,23,24,27,29]. Of these improvements, it seems that the last introduces the fewest additional parameters into the continuum solvation model.…”

“…Thus, using the multiconfigurational self-consistent reaction field (MCSCRF) procedure [20], linear [21,24], quadratic [41], and cubic [70] solvation response properties are computable, with (nonequilibrium) or without (equilibrium) consideration of inertial polarization effects.…”