Deuteration effects in the thermal conductivity of molecular glasses

Кривчиков, А. И.; Bermejo, Francisco Javier; Sharapova, I. V.; Korolyuk, O. A.; Romantsova, O. O.

doi:10.1063/1.3622630

Cited by 14 publications

(11 citation statements)

References 37 publications

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“…A rough estimate of the mass effect yields κ ∝ M −1/2 . These results however contrast with previous studies on other materials which have shown that the increase in molecular mass decreases the rate of phonon scattering [23,24]. The typical bell-like shape for κ(T ) for ordered phases in such a log-log plot is clearly observed and thus, after the maximum, κ(T ) decreases with temperature.…”

Section: Data Analysis and Resultscontrasting

confidence: 55%

Effects of site-occupation disorder on the low-temperature thermal conductivity of molecular crystals

Кривчиков

Vdovichenko

Korolyuk

et al. 2015

Journal of Non-Crystalline Solids

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The thermal conductivity of CBrnCl4−n,(n= 0,1,2) and 2-adamantanone (C10H14O) crystals which exhibit substitutional disorder has been measured for temperatures between 2 K and 150 K. Such temperatures comprise signatures of dynamical processes involving the site occupancy of the chlorine and bromine atoms for CBrnCl4−n,(n= 0,1,2) and the oxygen atom for (C10H14O), as it has been revealed by both, calorimetry and spectroscopic techniques. The data analysis is carried out in terms of several phonon scattering channels contributing to a resistive relaxation rate which can be represented by two contributions due to propagating phonons whose mean-free path exceeds half the phonon wavelength as well as a term attributed to localized short wavelength modes. The implications of the present findings for studies pertaining glassy dynamics are briefly discussed.

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Section: Data Analysis and Resultscontrasting

confidence: 55%

Effects of site-occupation disorder on the low-temperature thermal conductivity of molecular crystals

Кривчиков

Vdovichenko

Korolyuk

et al. 2015

Journal of Non-Crystalline Solids

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“…S7). Thus, the effect of H/D isotope substitution on the glass transition of water (ΔT g ≈10 K) is significantly stronger than in other hydrogenbonding materials such as ethanol (ΔT g ≈ 0 K) (12,46), PG (ΔT g ≈ 0.1 K), and glycerol (ΔT g ≈ 0.4 K) (45).…”

Section: Details Of Dielectric Spectroscopy Measurementsmentioning

confidence: 99%

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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“…It was demonstrated with protonated ethanol [1] that the thermal conductivity curves of orientational and structural glasses having basically different molecular disorderings were unexpectedly close in value and temperature dependence. This finding was then confirmed in the investigation of the thermal conductivity of deuterated ethanol [2]. The behavior of the thermal conductivity of ethanol glasses suggests that the acoustic phonon scattering in glasses is caused mainly by the orientational molecular disor- der rather than the structural one.…”

Section: Introductionmentioning

confidence: 65%

“…Of special interest are the temperature dependences of the thermal conductivity κ(T ) of these objects. They deviate from the corresponding dependences typical of orientationally-ordered molecular crystals: there is no phonon maximum in most of them [1][2][3]. The dependences κ(T ) also differ from those typically observed in structural glasses; they have no plateau and do not increase with a rising temperature [4].…”

Section: Introductionmentioning

confidence: 99%

Thermal conductivity of molecular crystals with self-organizing disorder

Кривчиков¹,

Vdovychenko²,

Korolyuk³

et al. 2014

Preprint

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The thermal conductivity of some orientational glasses of protonated C2H5OH and deuterated C2D5OD ethanol, cyclic substances (cyclohexanol C6H11OH, cyanocyclohexane C6H11CN , cyclohexene C6H10), and freon 112 (CF Cl2)2 have been analyzed in the temperature interval 2-130 K. The investigated substances demonstrate new effects concerned with the physics of disordered systems. Universal temperature dependences of the thermal conductivity of molecular orientational glasses have been revealed. At low temperatures, the thermal conductivity exhibits a universal behavior that can be described by the soft potential model. At relatively high temperatures, the thermal conductivity has a smeared maximum and than decreases with increase in the temperature, which occurs typically in crystalline structures. K e y w o r d s: thermal conductivity, orientational glass, phonon scattering, soft potential model.

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Deuteration effects in the thermal conductivity of molecular glasses

Cited by 14 publications

References 37 publications

Effects of site-occupation disorder on the low-temperature thermal conductivity of molecular crystals

Effects of site-occupation disorder on the low-temperature thermal conductivity of molecular crystals

Anomalously large isotope effect in the glass transition of water

Thermal conductivity of molecular crystals with self-organizing disorder

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