The Boson peak in supercooled water

Kumar, Pradeep; Wikfeldt, Thor; Schlesinger, Daniel; Pettersson, Lars G. M.; Stanley, H. Eugene

doi:10.1038/srep01980

Cited by 52 publications

(51 citation statements)

References 59 publications

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“…Preliminary measurements on the boson peak in deeply cooled water confined in nanopores [4] and protein surfaces [5] under ambient pressure have been reported. The measured spectra include a boson peak at about 6 meV, which only emerges below ∼230 K. A similar result was also observed in a computer simulation study [6]. Since this temperature is close to the ambient-pressure Widom line temperature T W ∼224 K (the Widom line is the locus of specific heat maxima [7]), the authors tentatively explained this phenomenon as due to transformation of the local structure of water from a predominantly high-density liquid (HDL) to a predominantly low-density liquid (LDL) form as T W is crossed from above.…”

supporting

confidence: 86%

Boson Peak in Deeply Cooled Confined Water: A Possible Way to Explore the Existence of the Liquid-to-Liquid Transition in Water

Wang

Liu

et al. 2014

Phys. Rev. Lett.

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The boson peak in deeply cooled water confined in nanopores is studied with inelastic neutron scattering. We show that in the (P, T) plane, the locus of the emergence of the boson peak is nearly parallel to the Widom line below ∼1600 bar. Above 1600 bar, the situation is different and from this difference the end pressure of the Widom line is estimated. The frequency and width of the boson peak correlate with the density of water, which suggests a method to distinguish the hypothetical "low-density liquid" and "highdensity liquid" phases in deeply cooled water. DOI: 10.1103/PhysRevLett.112.237802 PACS numbers: 61.20.Lc, 63.50.−x The boson peak is a broad peak observed at low frequencies (∼2-10 meV) in the inelastic neutron, x-ray, and Raman scattering spectra of many amorphous materials and supercooled liquids [1][2][3]. Preliminary measurements on the boson peak in deeply cooled water confined in nanopores [4] and protein surfaces [5] under ambient pressure have been reported. The measured spectra include a boson peak at about 6 meV, which only emerges below ∼230 K. A similar result was also observed in a computer simulation study [6]. Since this temperature is close to the ambient-pressure Widom line temperature T W ∼224 K (the Widom line is the locus of specific heat maxima [7]), the authors tentatively explained this phenomenon as due to transformation of the local structure of water from a predominantly high-density liquid (HDL) to a predominantly low-density liquid (LDL) form as T W is crossed from above. However, this experimental result is insufficient. First, it is clear that this emergence of the boson peak in the raw spectra depends on the energy resolution of the experimental facility. Second, and more importantly, the situation at high pressures has, heretofore, remained unknown. Therefore, without quantitative analysis of the entire spectra, including quasielastic and inelastic components at high pressure, definite conclusions cannot be drawn.In this Letter, we have measured the boson peak in deeply cooled water with a series of inelastic neutron scattering (INS) experiments in the temperature (T) range from 120 to 230 K and the pressure (P) range from 400 to 2400 bar employing the Disk Chopper Spectrometer (DCS) [8] at the National Institute of Standards and Technology (NIST) Center for Neutron Research and the Cold Neutron Chopper Spectrometer (CNCS) [9] at the Spallation Neutron Source of the Oak Ridge National Laboratory (ORNL). The DAVE software was used for the data reduction [10]. We find that below ∼1600 bar, the emergence of the boson peak is correlated (but does not overlap) with the Widom line and with the fragile-to-strong crossover (FSC) in deeply cooled water [11]. Above ∼1600 bar, the locus of the emergence of the boson peak in the (P, T) plane has a different slope as compared with its behavior below ∼1600 bar, and the end pressure of the Widom line is estimated by determining where the slope begins to change. Moreover, the (P, T) dependences of the shape of the boson peak are f...

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supporting

confidence: 86%

Boson Peak in Deeply Cooled Confined Water: A Possible Way to Explore the Existence of the Liquid-to-Liquid Transition in Water

Wang

Liu

et al. 2014

Phys. Rev. Lett.

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“…Then, considering that the order parameter of the hypothetical LLT is just the density [9], the boson peak provides a good way to examine the existence of the LLT. In addition, a previous study shows that the emergence of the boson peak in deeply cooled confined water tracks the Widom line of the possible LLT determined by the dynamic crossover below the critical pressure P [28,45]. And the locus of the emergence of the boson peak in the(P, T) plane changes the slope at the critical pressure [28].…”

mentioning

confidence: 81%

Pressure Effect on the Boson Peak in Deeply Cooled Confined Water: Evidence of a Liquid-Liquid Transition

et al. 2015

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The boson peak in deeply cooled water confined in nanopores is studied to examine the liquid-liquid transition (LLT). Below ∼180 K, the boson peaks at pressures P higher than ∼3.5 kbar are evidently distinct from those at low pressures by higher mean frequencies and lower heights. Moreover, the higher-P boson peaks can be rescaled to a master curve while the lower-P boson peaks can be rescaled to a different one. These phenomena agree with the existence of two liquid phases with different densities and local structures and the associated LLT in the measured (P, T) region. In addition, the P dependence of the librational band also agrees with the above conclusion. DOI: 10.1103/PhysRevLett.115.235701 PACS numbers: 64.70.Ja, 25.40.Fq, 63.50.-x Water is a continuing source of fascination to scientists because of its abnormal behavior at low temperatures T. Upon cooling, its thermodynamic properties, such as density, isobaric heat capacity, and isobaric thermal expansivity, deviate from those of simple liquids significantly [1][2][3][4]. In addition, glassy water, also called amorphous ice, exhibits polyamorphism. Experiments show that two kinds of amorphous ice, low-density amorphous ice (LDA) and high-density amorphous ice (HDA), exist at very low temperatures [5][6][7]. These two phases can transform to each other through a first-order-like transition [7,8]. To account for these mysterious phenomena, a "liquid-liquid critical point (LLCP)" scenario, which assumes a first-order low-density liquid (LDL) to high-density liquid (HDL) phase transition in the deeply cooled region of liquid water, has been proposed [9]. Therefore, experimental tests on the existence of the LDL and the HDL and the associated liquid-liquid transition (LLT) are important for understanding water. Nevertheless, such measurements are practically difficult due to the rapid crystallization of bulk water below the homogeneous nucleation temperature (235 K at 1 atm). To overcome this barrier and enter the deeply cooled region of water, different systems, including aqueous solutions [10][11][12][13][14], microsized water droplets [15], and confined water systems [16][17][18][19], have been prepared and studied. Particularly, when confined in a nanoporous silica matrix, MCM-41, with a 15-Å pore diameter, water can be kept in the liquid state at least down to 130 K [20,21]. Thus, the MCM-41-confined water system provides a chance to explore the hypothetical LLT.Recently, we observed a likely LLT in heavy water confined in MCM-41 by a density measurement. The associated phase diagram is shown in Fig. 1(a) [22]. However, the relevant measurements on the dynamic properties are still lacking. In fact, various dynamic properties, including the structural relaxation [10,16], the stretching vibration [10,11], the mean square displacement [23], etc., have been measured to study the phase behaviors of aqueous solutions or confined water. Examinations of FIG. 1 (color online). (a) Phase diagram of deeply cooled confined heavy water [22]. The inset shows th...

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“…Even though experimental evidence has been provided in the past for the presence of a Boson peak in HDA ice 152 , more recent neutron time-of-flight and backscattering spectroscopy results seem to rule out this possibility 153 . On the other hand, a Boson peak has been found in experiments on and simulations of protein hydration water 154,155 , simulations of supercooled water 156 and supercooled confined water 134 .…”

Section: The Boson Peakmentioning

confidence: 99%

X-ray and Neutron Scattering of Water

et al. 2016

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International audienceThis review article focuses on the most recent advances in X-ray and neutron scattering studies of water structure, from ambient temperature to the deeply supercooled and amorphous states, and of water diffusive and collective dynamics, in disparate thermodynamic conditions and environments. In particular, the ability to measure X-ray and neutron diffraction of water with unprecedented high accuracy in an extended range of momentum transfers has allowed the derivation of detailed O–O pair correlation functions. A panorama of the diffusive dynamics of water in a wide range of temperatures (from 400 K down to supercooled water) and pressures (from ambient up to multiple gigapascals) is presented. The recent results obtained by quasi-elastic neutron scattering under high pressure are compared with the existing data from nuclear magnetic resonance, dielectric and infrared measurements, and modeling. A detailed description of the vibrational dynamics of water as measured by inelastic neutron scattering is presented. The dependence of the water vibrational density of states on temperature and pressure, and in the presence of biological molecules, is discussed. Results about the collective dynamics of water and its dispersion curves as measured by coherent inelastic neutron scattering and inelastic X-ray scattering in different thermodynamic conditions are reported

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The Boson peak in supercooled water

Cited by 52 publications

References 59 publications

Boson Peak in Deeply Cooled Confined Water: A Possible Way to Explore the Existence of the Liquid-to-Liquid Transition in Water

Boson Peak in Deeply Cooled Confined Water: A Possible Way to Explore the Existence of the Liquid-to-Liquid Transition in Water

Pressure Effect on the Boson Peak in Deeply Cooled Confined Water: Evidence of a Liquid-Liquid Transition

X-ray and Neutron Scattering of Water

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