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Collective excitations and ultrafast dipolar solvation dynamics in water-ethanol binary mixture

Hazra, Milan K and Bagchi, Biman (2018) Collective excitations and ultrafast dipolar solvation dynamics in water-ethanol binary mixture. In: JOURNAL OF CHEMICAL PHYSICS, 148 (11).

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Official URL: http://dx.doi.org/10.1063/1.5019405


In order to understand the intermolecular vibrational spectrum and the collective excitations of waterethanol binary mixture, we investigate the density of states and the power spectrum using computer simulations aided by theory. We investigate in particular the spectra at intermediate to low frequencies (a few hundreds to few tens of cm(-1) 1) by calculating (i) the density of states from quenched normal modes, (ii) the power spectrum from velocity time correlation function, and (iii) the far infrared and dielectric spectra (that is, the Cole-Cole plot) from the total dipole moment time correlation function. The different spectra are in broad agreement with each other and at the same time reveal unique characteristics of the water-ethanol mixture. Inverse participation ratio reveals several interesting features. Libration of pure ethanol is more localized than that of pure water. With increasing ethanol content, we observe localization of the collective libration mode as well as of the hindered translational and rotational mode. An interesting mixing between the libration of water and ethanol is observed. Solvation dynamics of tryptophan measured by equilibrium energy fluctuation time correlation function show surprisingly strong non-linear dependence on composition that can be tested against experiments. Published by AIP Publishing.

Item Type: Journal Article
Additional Information: Copy right for the article belong to AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 11 Apr 2018 19:58
Last Modified: 11 Apr 2018 19:58
URI: http://eprints.iisc.ac.in/id/eprint/59513

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