The Dielectric Properties of Water and Heavy Water

Collie, C. H.; Hasted, J. B.; Ritson, D. M.

doi:10.1088/0959-5309/60/2/304

Cited by 242 publications

(89 citation statements)

References 7 publications

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“…1B, Inset). Our argument is also confirmed by water data at high temperature (36)(37)(38) where over-barrier relaxation should dominate (Fig. 1B, Inset).…”

Section: Significancesupporting

confidence: 82%

Anomalously large isotope effect in the glass transition of water

Gainaru

Agapov

Fuentes-Landete

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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We present the discovery of an unusually large isotope effect in the structural relaxation and the glass transition temperature T g of water. Dielectric relaxation spectroscopy of low-density as well as of vapor-deposited amorphous water reveal T g differences of 10 ± 2 K between H 2 O and D 2 O, sharply contrasting with other hydrogen-bonded liquids for which H/D exchange increases T g by typically less than 1 K. We show that the large isotope effect and the unusual variation of relaxation times in water at low temperatures can be explained in terms of quantum effects. Thus, our findings shed new light on water's peculiar low-temperature dynamics and the possible role of quantum effects in its structural relaxation, and possibly in dynamics of other low-molecularweight liquids.dynamics of water | isotope effect | quantum effects | glass transition | amorphous ice A lthough water is arguably the most important liquid for life, many of its properties remain puzzling (1, 2). In particular, its behavior in the "no-man's land" between 240 K and 150 K, its lowtemperature structural relaxation, and even its glass transition temperature (T g ) continue to be topics of active discussion (3-7).The unusually weak temperature dependence of viscosity near T g ∼136 K, estimated indirectly from crystallization rates, has long been known as one of water's startling features (8). In glassforming liquids the temperature dependence of viscosity or structural relaxation time τ is usually characterized by the fragility index (9):Materials such as SiO 2 and BeF 2 display Arrhenius-like τ(T) behavior with m ∼20-22 and are called strong, whereas those with fragility indices m ∼80 and higher exhibit pronounced superArrhenius variations of τ and are called fragile. Recent dielectric studies discovered an extremely weak temperature dependence of τ in low-density amorphous (LDA) water, with m ∼14 (10). This is by far the lowest fragility known for any liquid and even below its accepted lower limit, m ∼16 (9). Recent speculations ascribe this "superstrong" behavior of water to the impact that zero-point quantum fluctuations can have on structural dynamics (7). Because of the eminent role the atomic mass plays for quantum effects, H/D isotope substitution should have a significant bearing on the low-temperature dynamics of water. To address this question, we performed dielectric measurements on H 2 O and D 2 O prepared as LDA and vapor-deposited water (amorphous solid water, ASW). Details regarding the preparation of LDA water were presented earlier (10) and are briefly summarized in Materials and Methods together with ASW preparation, measurements details, and data analysis (for more details, see also Supporting Information). All of the measurements were repeated several times to confirm data reproducibility. The relaxation times τ for protonated LDA (H-LDA) water (Fig. 1A) as well as for ASW (Fig. 1B), although differing for the reasons given in Supporting Information, both confirm their extremely low fragility, m ∼14 ± 1. An Arrhenius ap...

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“…1B, Inset). Our argument is also confirmed by water data at high temperature (36)(37)(38) where over-barrier relaxation should dominate (Fig. 1B, Inset).…”

Section: Significancesupporting

confidence: 82%

Anomalously large isotope effect in the glass transition of water

Gainaru

Agapov

Fuentes-Landete

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The sample obtained in this way had a protein concentration of 11.5 mg/ml, and should be associated to a molecular weight of 9 x 106 (12 Fig. 1, but Assuming the interaction responsible for relaxation to be the same for molecules either in solution or in association with the protein, and using -7R values for water and 80% 2H20 calculated from dielectric relaxation data (19,20), and Tw values given by Krynicki (21) and Hindman (16) one computes for the limit Ho 0, using the data in Table 1, Tlpr = 1.8 X 10-4, 1.5 X 10-5,3.3 X 10-7sec [4] respectively for 'H, 2H, and 170 for 40, and for 22°, Tipr = 4.1 X 10-4,4.1 X 10-5, and 7.8 X 10-7sec. [5] Arguments have been made previously that 'H and 2H exchange mainly as whole water molecules, as does 170, and not by an acid-base catalyzed exchange.…”

Section: Methodsmentioning

confidence: 99%

Protein-water interaction studied by solvent 1H, 2H, and 17O magnetic relaxation.

Koenig¹,

Hallenga²,

Shporer³

1975

Proc. Natl. Acad. Sci. U.S.A.

103

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Previous studies of the magnetic field de- Solvent proton relaxation in protein solutions can be accounted for reasonably well within the framework of a simple model of water exchange between the bulk solvent, in which the protons are assumed not to interact with the solute, and regions on or near the protein where the rotational motion of the protein molecules is conveyed to the water molecules. If it is assumed that the water molecules in the latter region attach rigidly to the protein, then one can readily estimate (1) the number n of such attachment sites to be about 3 for lysozyme and to increase at least as fast as the surface area for larger proteins (K. Hallenga and S. H. Koenig, to be published). If the attachment is assumed not rigid, the derived value of n is greater by a small factor, but is still-and this is the major unsettling feature of this simple two-site model-only a few percent of the number of water molecules in the first hydration layer (1). The nature of such special sites is difficult to conceive.From the data for proton relaxation, one can only set fairly wide limits on the value (or distribution of values) of TM, the mean lifetime of a water molecule on the protein and a quantity which is a feature of the model itself. The application of the model gives TM > TR 10-7 sec, and TM < Tipr -10-4 sec, the relaxation time of the protons when on the protein. In an attempt to get a better measurement of TM, as well as to test other predictions of the models, we measured and report here comparisons of the magnetic field dependence of the relaxation rate of 170 in solutions of protein in 17O-enriched water, and deuterons in 2H20 solutions, with the proton data. Since deuterons in water relax about 10 times faster than protons, and 170 nuclei about 100 times faster than deuterons, the upper limit on the model value for TM is drastically reduced and the range for TM is drastically narrowed. We have also made measurements on an extremely large protein-hemocyanin associated to a M.W. of 9 X 106-in order to increase the lower limit of TrM. The experiments were quite successful in that -TM was squeezed into nonexistence: i.e., the data reported below cannot be explained by a simple two-region model with a defined life-

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“…M. Bruma and S. Chatterjee used a circular cavity resonating in Eq-^q mode with capillary tube specimen and tuning plunger. C. H. Collie et al 8 …”

Section: Introductionmentioning

confidence: 99%