scholarly journals Experimental observation of the liquid-liquid transition in bulk supercooled water under pressure

Science ◽  
2020 ◽  
Vol 370 (6519) ◽  
pp. 978-982 ◽  
Author(s):  
Kyung Hwan Kim ◽  
Katrin Amann-Winkel ◽  
Nicolas Giovambattista ◽  
Alexander Späh ◽  
Fivos Perakis ◽  
...  
Keyword(s):  
Time Scales ◽  
Supercooled Water ◽  
Supercooled Liquid ◽  
Laser Pulses ◽  
High Density ◽  
Liquid Transition ◽  
Probe Delay ◽  
Sample Density ◽  
Order Of Magnitude ◽  
Isochoric Heating

We prepared bulk samples of supercooled liquid water under pressure by isochoric heating of high-density amorphous ice to temperatures of 205 ± 10 kelvin, using an infrared femtosecond laser. Because the sample density is preserved during the ultrafast heating, we could estimate an initial internal pressure of 2.5 to 3.5 kilobar in the high-density liquid phase. After heating, the sample expanded rapidly, and we captured the resulting decompression process with femtosecond x-ray laser pulses at different pump-probe delay times. A discontinuous structural change occurred in which low-density liquid domains appeared and grew on time scales between 20 nanoseconds to 3 microseconds, whereas crystallization occurs on time scales of 3 to 50 microseconds. The dynamics of the two processes being separated by more than one order of magnitude provides support for a liquid-liquid transition in bulk supercooled water.

scholarly journals Theoretical framework for classification and prediction of ultrafast and strong-field phenomena in solids

2019 ◽  
Vol 205 ◽  
pp. 04013
Author(s):  
Stanislav Yu. Kruchinin ◽  
Ferenc Krausz ◽  
Vladislav S. Yakovlev
Keyword(s):  
Density Matrix ◽  
Time Scales ◽  
Strong Field ◽  
Laser Pulses ◽  
Theoretical Framework ◽  
Ultrashort Laser Pulses ◽  
Matrix Equations ◽  
Electron Dynamics ◽  
Characteristic Energy ◽  
Ultrashort Laser

We study the characteristic energy and time scales describing the coherent electron dynamics and decoherence phenomena in solids interacting with ultrashort laser pulses. Our analysis resulted in the derivation system of dimensionless adiabaticity parameters and derivation of the non-Markovian density-matrix equations applicable on arbitrary short timescales.

scholarly journals Linear and nonlinear absolute phase effects in interactions of ulrashort laser pulses with a metal nano-layer or with a thin plasma layer

2007 ◽  
Vol 25 (3) ◽  
pp. 379-390 ◽  
Author(s):  
S. Varró
Keyword(s):  
Laser Pulse ◽  
Phase Difference ◽  
Plasma Layer ◽  
Thin Foil ◽  
Laser Pulses ◽  
Thomson Scattering ◽  
Carrier Envelope Phase ◽  
Absolute Phase ◽  
High Intensity Laser ◽  
Order Of Magnitude

It has been shown that in the scattered radiation, generated by an ultrashort laser pulse impinging on a metal nano-layer, non-oscillatory wakefields appears with a definite sign. The magnitude of these wakefields is proportional to the incoming field strength, and the definite sign of them is governed by the cosine of the carrier-envelope phase difference of the incoming pulse. When we let such a Wakefield excite the electrons of a secondary target (say an electron beam, a metal surface or a gas jet), we can obtain 100 percent modulation in the electron signal in a given direction. This scheme can serve as a basis for the construction of a robust linear carrier-envelope phase difference meter. At relativistic laser intensities, the target is considered as a plasma layer in vacuum produced from a thin foil by a prepulse, which is followed by the main high-intensity laser pulse. The nonlinearities stemming from the relativistic kinematics lead to the appearance of higher-order harmonics in the scattered spectra. In general, the harmonic peaks are downshifted due to the presence of an intensity-dependent factor. This phenomenon is analogous to the famous intensity-dependent frequency shift in the nonlinear Thomson scattering on a single electron. In our analysis, an attention has also been paid to the role of the carrier-envelope phase difference of the incoming few-cycle laser pulse. It is also shown that the spectrum has a long tail where the heights of the peaks vary practically within one order of magnitude forming a quasi-continuum. Fourier synthesizing the components from this plateau region attosecond pulses has obtained.

scholarly journals Reversible structural transformations in supercooled liquid water from 135 to 245 K

Science ◽  
2020 ◽  
Vol 369 (6510) ◽  
pp. 1490-1492
Author(s):  
Loni Kringle ◽  
Wyatt A. Thornley ◽  
Bruce D. Kay ◽  
Greg A. Kimmel
Keyword(s):  
Structural Changes ◽  
Supercooled Water ◽  
Supercooled Liquid ◽  
Structural Transformations ◽  
Limited Data ◽  
Supercritical Regime ◽  
Water Films ◽  
Fundamental Understanding ◽  
Full Temperature ◽  
State Configuration

A fundamental understanding of the unusual properties of water remains elusive because of the limited data at the temperatures and pressures needed to decide among competing theories. We investigated the structural transformations of transiently heated supercooled water films, which evolved for several nanoseconds per pulse during fast laser heating before quenching to 70 kelvin (K). Water’s structure relaxed from its initial configuration to a steady-state configuration before appreciable crystallization. Over the full temperature range investigated, all structural changes were reversible and reproducible by a linear combination of high- and low-temperature structural motifs. The fraction of the liquid with the high-temperature motif decreased rapidly as the temperature decreased from 245 to 190 K, consistent with the predictions of two-state “mixture” models for supercooled water in the supercritical regime.

Markov-modulated traffic with nearly complete decomposability characteristics and associated fluid queueing models

1995 ◽  
Vol 27 (04) ◽  
pp. 1144-1185
Author(s):  
Kimon P. Kontovasilis ◽  
Nikolas M. Mitrou
Keyword(s):  
State Space ◽  
Time Scales ◽  
Structural Characteristics ◽  
Queueing Systems ◽  
Queuing Models ◽  
Aggregation Techniques ◽  
Phase Perturbation ◽  
Order Of Magnitude ◽  
Markov Modulated ◽  
The Individual

This paper considers fluid queuing models of Markov-modulated traffic that, due to large differences in the time-scales of events, possess structural characteristics that yield a nearly completely decomposable (NCD) state-space. Extension of domain decomposition and aggregation techniques that apply to approximating the eigensystem of Markov chains permits the approximate subdivision of the full system to a number of small, independent subsystems (decomposition phase), plus an ‘aggregative' system featuring a state-space that distinguishes only one index per subsystem (aggregation phase). Perturbation analysis reveals that the error incurred by the approximation is of an order of magnitude equal to the weak coupling of the NCD Markov chain. The study in this paper is then extended to the structure of NCD fluid models describing source superposition (multiplexing). It is shown that efficient spectral factorization techniques that arise from the Kronecker sum form of the global matrices can be applied through and combined with the decomposition and aggregation procedures. All structural characteristics and system parameters are expressible in terms of the individual sources multiplexed together, rendering the construction of the global system unnecessary. Finally, besides providing efficient computational algorithms, the work in this paper can be recast as a conceptual framework for the better understanding of queueing systems under the presence of events happening in widely differing time-scales.

scholarly journals Measurements of the Vapor Pressure of Supercooled Water Using Infrared Spectroscopy

2008 ◽  
Vol 25 (9) ◽  
pp. 1724-1729 ◽  
Author(s):  
Will Cantrell ◽  
Eli Ochshorn ◽  
Alexander Kostinski ◽  
Keith Bozin
Keyword(s):  
Infrared Spectroscopy ◽  
Vapor Pressure ◽  
Liquid Water ◽  
Water Film ◽  
Supercooled Water ◽  
Supercooled Liquid ◽  
Quantitative Change ◽  
Wetting Transition ◽  
Higher Temperature

Abstract Measurements are presented of the vapor pressure of supercooled water utilizing infrared spectroscopy, which enables unambiguous verification that the authors’ data correspond to the vapor pressure of liquid water, not a mixture of liquid water and ice. Values of the vapor pressure are in agreement with previous work. Below −13°C, the water film that is monitored to determine coexistence of liquid water (at one temperature) and ice (at another, higher, temperature) de-wets from the hydrophilic silicon prism employed in the authors’ apparatus. The de-wetting transition indicates a quantitative change in the structure of the supercooled liquid.

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