The dielectric relaxation time of supercooled water

Abstract

The complex dielectric constant of liquid water was measured at 9.61 GHz down to −18 °C by means of a two resonant cavities apparatus. The static dielectric constant of bulk samples was also measured at 27.5 MHz down to −16.5 °C using a resonant circuit technique. From the analysis of the experimental results it follows that water in the metastable region has practically a single dielectric relaxation time τ. An analysis of the dynamic properties of water using our results and available data in literature, is presented. The main result is that self-diffusion DS, shear viscosity η, and τ below 0 °C are related to the same mechanism. For T≳0°C another mechanism affecting η rises.

The Effects of Water on the Dielectric Properties of Aluminum-Based Nanocomposites

“…In other related work [21,48,49], such mid frequency relaxation behavior has been attributed to water absorbed at the nanoparticle interfaces. Compared to analogous silica-based systems [37,38], the major relaxation frequency here is much lower ~250 Hz, indicating a significantly reduced mobility of the water, as discussed in detail elsewhere [18][19][20][21].…”

“…Comrie et al [19], for example, report a correlation between changes in the mechanical strength of adhesive joints and variation in the observed dielectric spectrum. Free, liquid water is characterized by a dielectric relaxation process at about 9.6 GHz [20], but the presence of local interactions can dramatically affect this. Lau et al [21] reported on the dielectric response of nanosilica/polyethylene systems and showed that water accumulates at nanofiller surfaces to an extend that is dependent upon the nanofiller surface chemistry.…”

The complex dielectric constant of pure and sea water from microwave satellite observations

“…Stogryn [13] used a fit based on the measurements of [29]. Both fits differ by less than 0.03% over the temperature range between C and C. They are also in excellent agreement with the measurements of [28] and the low temperature values of [33]. For reference, we use the fit given in [13] (7)…”

Reorganization Energy of Electron Transfer in Viscous Solvents above the Glass Transition

“…32,38 In particular, the peak ω max of the dielectric loss ′′-(ω) shifts to lower frequencies with cooling the solvent. The corresponding Debye relaxation time, τ D ) 1/ω max (diamonds in Figure 3), compares very well to the experimentally reported values 32,33 (closed diamonds and half-open triangles in Figure 3).…”

“…32,38 In particular, the peak ω max of the dielectric loss ′′-(ω) shifts to lower frequencies with cooling the solvent. The corresponding Debye relaxation time, τ D ) 1/ω max (diamonds in Figure 3), compares very well to the experimentally reported values 32,33 (closed diamonds and half-open triangles in Figure 3). A similarly good agreement was reported previously by Rønne et al 33 for MD simulations in a narrower temperature range (271.5 e T e 368.15) on a smaller system (216 SPC/E molecules, 4 ns runs with the time step of 2 fs).…”