Pressure and Temperature Dependence of the Longitudinal Deuterium Relaxation Times in Supercooled Heavy Water to 300 MPa and 188 K

Abstract

The longitudinal deuteron relaxation times T1 in heavy water have been determined at 15.4 MHz in the temperature range from T = 283 K to 188 K and up to pressures of 300 MPa. Between 283 K and 200 K all isotherms exhibit pronounced maxima of T1 in the pressure range between 150 MPa and 300 MPa. This maximum is most pronounced in the 242 K isotherm, where T1 increases more than fourfold from 17 ms at 0.1 MPa to 73 ms at 250 MPa. The 225 MPa isobar runs at 192 K through a minimum: T1 = 0.5 ms. Under the assumption of isotropic reorientation one derives from the minimum condition (ω0 ·τθ ⋍ 0.62) the deuteron quadrupole coupling constant for D2O to CDQC = 214 ± 12 kHz. The isobaric temperature dependence of the correlation times τθ can be described at p ≥ 200 MPa by the VTF‐equation. At p ≤ 100 MPa τθ increases faster with falling temperature than predicted by the VTF‐equation. In this range the isobars are best represented by an equation proposed by Speedy and Angell: The determination of τθ permits an estimate of the viscosity η and the self‐diffusion coefficient D for D2O in the supercooled range. Around T = 190 K and p = 225 MPa one gets η ⋍ 4 Pa · s and D ⋍ 6 · 10−9 cm2/s.

Supercooled Water

“…As in the quasielastic neutron scattering study discussed above, the second Lorentzian components, in this case the narrow one, can be associated with a relatively long time constant process associated with rotational diffusion ; its time constant and non-Arrhenius temperature dependence correlate well with those of dielectric (103) and NMR (98)(99)(100) studies. The short time process, on the other hand, has a much smaller temperature dependence, which, as best can be discerned from the data at hand, fo llows an Arrhenius law.…”

“…Normal pressure studies on emulsions were first made by Hindman et al (48,97), and the techniq ue has since been exp loited with great success by Lang & Lu demann (34,(98)(99)(100), who, using Yamada's HF-strengthened glass fo r samp le containment (101), have exp lored the pressure regime up to 300 MPa, and pushed the measurements down to as low as -86°C.…”

Inverse temperature transition of elastin like motifs in major ampullate dragline silk: MD simulations of short peptides and NMR studies of water dynamics

“…Our findings indicated that over time scales from 10 μ s to 200 ms no exchange was observed. The peaks with T 1 > T 2 have characteristics reminiscent of the properties of supercooled heavy water 41 and heavy water in ice 42 where T 1 > T 2 was observed. Below, we make the assumption that a complex network of hydrogen bonding occurs between water molecules and between water and the protein surface and analyze the relaxation behavior by the same model used in reference 41 .…”

“…The model in the formulation above assumes that the motion of the water molecule may be divided into fast oscillatory motions and slower diffusional processes 41 . Following Lang et.…”

Physics of Water and Ice: Implications for Cryofixation

“…approx. 1500 times that of pure water; Lang and Ludemann 1980). This high viscosity must have implications for cryofixation at high pressures (see Moor,Chap.…”