Low-temperature specific heat of structural and orientational glasses of simple alcohols

Ramos, M. A.; Talón, C.; Riobóo, R. J. Jiménez; Vieira, S.

doi:10.1088/0953-8984/15/11/323

Cited by 66 publications

(94 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1). The size of this effect contrasts with that for other hydrogen-bonded liquids (11,12) that show ΔT g ≤1 K upon H/D substitution (see also Supporting Information).…”

mentioning

confidence: 61%

See 1 more Smart Citation

Anomalously large isotope effect in the glass transition of water

Gainaru

Agapov

Fuentes-Landete

et al. 2014

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

View full text Add to dashboard Cite

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...

show abstract

“…1). The size of this effect contrasts with that for other hydrogen-bonded liquids (11,12) that show ΔT g ≤1 K upon H/D substitution (see also Supporting Information).…”

mentioning

confidence: 61%

“…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: 94%

Anomalously large isotope effect in the glass transition of water

Gainaru

Agapov

Fuentes-Landete

et al. 2014

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

View full text Add to dashboard Cite

show abstract

“…17 Although there is still no consensus even about the proper experimental data, 25,28 most authors claim to find that ω IR ≈ ω BP , in some cases only for the transverse phonons ω IR T ≈ ω BP . 27 In particular, glass-forming molecular liquids are interesting and appealing model systems to investigate the universal low-temperature properties of glasses, since they often allow one to control several key variables such as comparing different isotopic compositions [29][30][31] or different isomers for the same substance, 30,[32][33][34] or using the existence of polymorphism to critically compare phases with different kinds of disorder. [35][36][37][38][39] In addition, these molecular liquids offer an easy and convenient temperature range to explore liquid-solid phase transitions such as the glass transition, and other relaxational processes.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature thermal and elastoacoustic properties of butanol glasses: Study of position isomerism effects around the boson peak

et al. 2012

View full text Add to dashboard Cite

We have concurrently measured the specific heat, the thermal conductivity, and the longitudinal and transverse sound velocities at low temperature of glasses from different isomers of butanol (n-butanol, sec-butanol and isobutanol), as well as the low-temperature specific heat for the crystals of n-butanol, isobutanol and tert-butanol. Whereas the elastic constants both for crystals and glasses are found to be almost independent of the position of the hydrogen bonds, the thermal properties at low temperatures of these glasses at a few kelvin (around the boson peak in the reduced specific heat or around the plateau in the thermal conductivity) are found to vary strongly. Our experiments clearly contradict other works or models claiming a Debye scaling of the boson peak, and hence of the excess low-temperature specific heat of glasses. Data analysis based upon the soft-potential model and its extensions allows us to estimate the Ioffe-Regel limit in these and other alcohol glasses, finding a correlation with the boson-peak position in agreement with that previously reported by other groups.

show abstract

“…Comparison of elastic and specific-heat data for several glasses, including the SPM quadratic fit of equation (6). The elastic data are as follows: SiO 2 , Se, PMMA, PS, and CaK(NO 3 ) 3 , taken from the review article by Pohl et al (2002); (B 2 O 3 ) 100-x (Na 2 O) x , from Krause and Kurkjian (1978); glycerol, after Ramos et al (2003). The specific-heat data are as follows: SiO 2 , from Zeller and Pohl (1971) and Buchenau et al (1986);Se, from Brand and Löhneysen (1991); PMMA and PS, from Choy et al (1970) and Stephens et al (1972); CaK(NO 3 ) 3 , from Sokolov et al (1997); (B 2 O 3 ) 100-x (Na 2 O) x , from Piñango et al (1990) and Ramos et al (1990); glycerol, from Talón et al (2002).…”

mentioning

confidence: 99%

Are the calorimetric and elastic Debye temperatures of glasses really different?

Ramos

2004

Philosophical Magazine

View full text Add to dashboard Cite

Below 1 K, the specific heat C p of glasses depends approximately linearly on temperature T, in contrast with the cubic dependence observed in crystals, and which is well understood in terms of the Debye theory. That linear contribution has been ascribed to the existence of twolevel systems as postulated by the Tunnelling Model. Therefore, a least-squares linear fit3 has been traditionally used to determine the specific-heat coefficients, though systematically providing calorimetric cubic coefficients exceeding the elastic coefficients obtained from sound-velocity measurements, that is C 3 > C Debye . Nevertheless, C p still deviates from the expected C Debye (T) ∝ T 3 dependence above 1 K, presenting a broad maximum in C p / T 3 which originates from the so-called boson peak, a maximum in the vibrational density of states g(ν)/ν 2 at frequencies ν ~ 1 THz. In this work, it is shown that the apparent contradiction between calorimetric and elastic Debye temperatures long observed in glasses is due to the neglect of the low-energy tail of the boson peak (which contribute as C p ∝ T 5 , following the Soft-Potential Model). If one hence makes a quadratic fit C p = C 1 T + C 3 T 3 + C 5 T 5 in the physically-meaningful temperature range, an agreement C 3 ≈ C Debye is found within experimental error for several studied glasses.

show abstract

Low-temperature specific heat of structural and orientational glasses of simple alcohols

Cited by 66 publications

References 29 publications

Anomalously large isotope effect in the glass transition of water

Anomalously large isotope effect in the glass transition of water

Low-temperature thermal and elastoacoustic properties of butanol glasses: Study of position isomerism effects around the boson peak

Are the calorimetric and elastic Debye temperatures of glasses really different?

Contact Info

Product

Resources

About