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Title: Picosecond solvation dynamics—A potential viewer of DMSO—Water binary mixtures

In this work, we have investigated the composition dependent anomalous behavior of dimethyl sulfoxide (DMSO)-water binary mixture by collecting the ultrafast solvent relaxation response around a well known solvation probe Coumarin 480 (C480) by using a femtosecond fluorescence up-conversion spectrometer. Recent molecular dynamics simulations have predicted two anomalous regions of DMSO-water binary mixture. Particularly, these studies encourage us to investigate the anomalies from experimental background. DMSO-water binary mixture has repeatedly given evidences of its dual anomalous nature in front of our systematic investigation through steady-state and time-resolved measurements. We have calculated average solvation times of C480 by two individual well-known methods, among them first one is spectral-reconstruction method and another one is single-wavelength measurement method. The results of both the methods roughly indicate that solvation time of C480 reaches maxima in the mole fraction of DMSO X{sub D} = 0.12–0.17 and X{sub D} = 0.27–0.35, respectively. Among them, the second region (X{sub D} = 0.27–0.35) is very common as most of the thermodynamic properties exhibit deviation in this range. Most probably, the anomalous solvation trend in this region is fully guided by the shear viscosity of the medium. However, the first region is the most interesting one. In this regionmore » due to formation of strongly hydrogen bonded 1DMSO:2H{sub 2}O complexes, hydration around the probe C480 decreases, as a result of which solvation time increases.« less
Authors:
; ; ; ; ; ;  [1]
  1. Department of Chemistry, Indian Institute of Technology, Kharagpur, WB 721302 (India)
Publication Date:
OSTI Identifier:
22416080
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BINARY MIXTURES; CHEMICAL BONDS; COMPLEXES; CONVERSION; COUMARIN; DMSO; FLUORESCENCE SPECTROSCOPY; HYDRATION; MOLECULAR DYNAMICS METHOD; POTENTIALS; RELAXATION; SHEAR; SOLVENTS; THERMODYNAMIC PROPERTIES; TIME RESOLUTION; VISCOSITY; WATER