Studies of the inertial component of polar solvation dynamics

Abstract

We describe results of computer simulations and sub-picosecond time-resolved fluorescence experiments on the solvation dynamics of 1-aminonapthalene and coumarin 153 in acetonitrile and methanol. Both the simulations and experiments point to the importance of fast, inertial components in the solvation response in these systems. Where direct comparisons between the experiment and simulation are possible, the agreement is found to be quite good. We also consider application of a simple theory for the solvation response in order to make some predictions about the likely importance of the inertial component in a variety of common solvents. 9This article is copyrighted as indicated in the abstract. Reuse of AIP content is subject to the terms at:http://scitation.aip.org/termsconditions. Downloaded to IP: 128.32.208.2 On: Wed, 13 Nov 2013 23:36:09 C(t ) = a t exp(-to2t 2 / 2) + a 2 exp(-t / x2) + a3 exp(-t/'t 3) Amplitudes are given in parenthesis. The column marked "c gives the average of the exponential time constants and the biexponential parameters (if applicable).

Picosecond time-dependent Stokes shift studies of fluoroprobe in liquid solution

“…Fortunately, although a large fraction of the dynamics cannot be monitored, the remaining experimental Stokes shift is still quite large and exceeds that of many other common solvation probes, e.g. the coumarine dyes, notwithstanding the fact that the latter probes were studied in more polar solvents and at much higher time resolution [11,47,48]. This clearly illustrates that fluoroprobe is an exceptionally good solvation probe [12][13][14][15][16][17].…”

Nonlinear, Nonpolar Solvation Dynamics in Water: The Roles of Electrostriction and Solvent Translation in the Breakdown of Linear Response

“…For dielectric solvation, the time evolution of the relaxation is well understood and is usually classified into three regimes. First, an initial Gaussian response results from the inertial rotational motions of solvent molecules in the first solvation shell; 14,26 in polar solvents such as water 9,10,15,16,27 or acetonitrile, 13,28 this inertial component can account for 60-80% of the total solvent relaxation. After the inertial response is complete, a subsequent librational relaxation occurs, characterized by rapid, damped oscillatory solvent rotational motions.…”

Molecular theory of ion solvation dynamics in water, acetonitrile and methanol: A unified microscopic description of collective dynamics in dipolar liquids

“…This ultrafast component seems to originate from the fast macroscopic relaxation mode of the solvent (Roy and Bagchi 1993a). In contrast, experimental (Kahlow et al 1989;Maroncelli et al 1993) and computer simulation (Fonseca and Ladanyi 1991;Maroncelli et al 1993) studies reveal methanol to be a rather different solvent, in not only being much slower, but also being nonlinear in its response to the sudden creation of an electrical charge in it. In this paper, a theoretical study of the solvation dynamics of a rigid ion in these three liquids is presented.…”

“…Since experimental results are not yet fully available for liquid methanol, we compare our results with the simulations (Maroncelli et al 1993). As the molecules are not polarizable in the simulated system, the polarizability is ignored by setting the optical frequency equal to 1 and the 3 Yparameter equal to 4.3276.…”

“…Our understanding of the solvation dynamics of charged species in dipolar liquids has undergone a renaissance in recent years (Bagchi 1989;Barbara and Jarzeba 1990;Maroncelli et al 1993;Roy and Bagchi 1993). Experiments (Rosenthal et al 1991) and computer simulations (Maroncelli and Fleming 1988) have shown that an ultrafast Gaussian component dominates the relaxation in both liquid acetonitrile and water.…”