Nonlinear effects of number density of solvent molecules on solvation dynamics

Abstract

For the number density of solvent molecules, nonlinear effects on solvation dynamics are studied using the dynamical density functional method. The present method includes nonlinear coupling between the number density and a polarization field only in the free energy functional. By means of the nonlinear free energy functional, nonlinear differential-integral equations are developed for the polarization field and number density. Numerical calculations show that solvent molecules relax more slowly around an ion than around a neutral solute. This result agrees qualitatively with nonlinear effects observed in many molecular dynamics simulations. In addition, the nonlinear dynamics of hydrogen bonds can be understood by considering the slow relaxation of the number density of solvent molecules.

Polar and Nonpolar Solvation Dynamics, Ion Diffusion, and Vibrational Relaxation: Role of Biphasic Solvent Response in Chemical Dynamics

“…(4.7) is exact (within mean field treatment) to the first order; which was first noted by Calef and Wolynes [133]. The system-atic inclusion of these higher-order terms will, of course, introduce nonlinearity in solvation energy relaxation [200].…”

Derivation of the nonlinear fluctuating hydrodynamic equation from the underdamped Langevin equation

“…This infinite form is also justified by discretization. First, we represent ρ in equation ( 5), g α in equation ( 6) and M αβ in equation (10) in the discretized form as follows:…”

Time-Dependent Density Functional Theory Formulated Using the Interaction-Site Model

“…Many phenomena show profound effects of inhomogeneous fields due to solutes on the dynamics of molecular liquids. When a solute particle is small [1][2][3][4][5] and solvents are mixtures, [5][6][7][8][9][10][11][12][13][14][15] the solute affects solvation dynamics nonlinearly. The effects of the solute also cause a deviation in solvation dynamics from the Gaussian process.…”

“…To study such effects, the time-dependent density functional theory (TDDFT) has been developed, [4][5][6][26][27][28][29][30][31][32][33][34][35][36] although studies using the theory have been restricted to simple liquids. The TDDFT can adequately deal with the inhomogeneous distribution of solvent molecules caused by solute molecules.…”

“…In fact, the TDDFT has been successful in studying nonlinear effects on the solvation dynamics of simple liquids. [4][5][6][26][27][28][29][30][31][32] Since the TDDFT, however, is applied only to simple liquids, it is necessary to extend the theory to molecular liquids.…”