Separate dynamics of solute and solvent in water–glucose solutions by depolarized light scattering

Terahertz Absorption Spectroscopy of a Liquid Using a Polarity Probe: A Case Study of Trehalose/Water Mixtures

“…It is assigned to rotational relaxation of the hydrated trehalose solute by analogy to results from dielectric relaxation of maltotriose [25] and glucose [26,27] solutions, which were confirmed by depolarized Rayleigh scattering. [28] 2) The dynamics of the solution differ from those of pure water. The rotational water mode D 1 loses amplitude and is blue-shifted (becomes faster) as the trehalose concentration reaches 0.5 m, and it is strongly reduced when the concentration is raised further to 1.0 m. The water mode D 2 at higher frequency (ca.…”

Structural and dynamical properties of glucose aqueous solutions by depolarized Rayleigh scattering

“…6 The main conclusions of such previous studies were: (1) a slow relaxation process (ranging from ¾30 to ¾120 ps within the 0.005-0.12 range of glucose/water mole ratio f g ), can be clearly revealed in high resolution DRS spectra and attributed to the rotational diffusion of glucose molecules. The corresponding average relaxation time < g >D gˇg was found to increase exponentially with glucose molar fraction X g and was interpreted in terms of the Stokes-Einstein-Debye (SED) relationship; 5 (2) the water relaxation time W at picosecond time scales, described as hydrogen bond (H-bond) lifetime, was found to increase with f g . A linear increase of W vs f g detected at lower concentrations is compatible with a description which takes into account bulk and hydrating water contributions.…”

“…In this context, a very recent study on aqueous solutions of the basic monosaccharide glucose gave evidence into the capability of the high resolution depolarized Rayleigh scattering (DRS) in distinguishing spectral features due to solute and solvent dynamics. 5 The susceptibility 00 ω , obtained from 0.01 to 1000 cm 1 , has been modeled as the sum of four contributions: a Cole-Davidson (CD) and a Debye functions to reproduce the glucose and water-relaxation modes; and two damped harmonic oscillator (DHO) functions for the resonances at 50 and 170 cm 1 due to the intermolecular bending and stretching modes of water molecules:…”

Vibrational Properties of Cyclodextrin–Water Solutions Investigated by Low-Frequency Raman Scattering: Temperature and Concentration Effects

“…In this context, recently, depolarized light scattering has been used by some of us as a powerful tool to distinguish spectral features coming from solute rotational dynamics, hydrogen bonding solvent dynamics, and vibrational intermolecular modes of saccharides and proteins aqueous solutions (Rossi et al, submitted for publication). [28][29][30][31][32] Here, making use of low-frequency depolarized Raman spectra, we focus the attention on the vibrational properties of CD-water solutions. In fact, the ability of CD to form hydrogen bonds with water is expected to modify the regular network of water-water hydrogen bonds in the solvent molecules placed around the solute, and such changes should in principle influence the low-wavenumber vibrational spectrum of water.…”