Ice Ih
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Ab initio thermodynamics of liquid and solid water Open
Thermodynamic properties of liquid water as well as hexagonal (Ih) and cubic (Ic) ice are predicted based on density functional theory at the hybrid-functional level, rigorously taking into account quantum nuclear motion, anharmonic fluctu…
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Phase Diagram of a Deep Potential Water Model Open
Using the Deep Potential methodology, we construct a model that reproduces accurately the potential energy surface of the SCAN approximation of density functional theory for water, from low temperature and pressure to about 2400 K and 50 G…
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A new phase diagram of water under negative pressure: The rise of the lowest-density clathrate s-III Open
Researchers predict a new ice clathrate structure as the most stable ice polymorph with the lowest density in a negative-pressure region.
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The hydrogen-bond network of water supports propagating optical phonon-like modes Open
The local structure of liquid water as a function of temperature is a source of intense research. This structure is intimately linked to the dynamics of water molecules, which can be measured using Raman and infrared spectroscopies. The as…
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Phase Equilibrium of Water with Hexagonal and Cubic Ice Using the SCAN Functional Open
Machine learning models are rapidly becoming widely used to simulate complex physicochemical phenomena with ab initio accuracy. Here, we use one such model as well as direct density functional theory (DFT) calculations to investigate the p…
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Molecular Origin of the Vibrational Structure of Ice I<sub>h</sub> Open
An unambiguous assignment of the vibrational spectra of ice Ih remains a matter of debate. This study demonstrates that an accurate representation of many-body interactions between water molecules, combined with an explicit treatment of nu…
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Lattice constants and expansivities of gas hydrates from 10 K up to the stability limit Open
The lattice constants of hydrogenated and deuterated CH4-, CO2-, Xe- (clathrate structure type I) and N2-hydrates (clathrate structure type II) from 10 K up to the stability limit were established in neutron- and synchrotron diffraction ex…
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Isobaric first-principles molecular dynamics of liquid water with nonlocal van der Waals interactions Open
We investigate the structural properties of liquid water at near ambient conditions using first-principles molecular dynamics simulations based on a semilocal density functional augmented with nonlocal van der Waals interactions. The adopt…
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Observation and Identification of a New OH Stretch Vibrational Band at the Surface of Ice Open
We study the signatures of the OH stretch vibrations at the basal surface of ice using heterodyne-detected sum-frequency generation and molecular dynamics simulations. At 150 K, we observe seven distinct modes in the sum-frequency response…
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Effect of salt on the H-bond symmetrization in ice Open
Significance Ice-VII and ice-X phases are the most stable forms of ice at high temperature and extreme pressures, typical of the interiors of satellites and planets. The phase transition between them is a prototypical case of quantum-drive…
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Brine rejection and hydrate formation upon freezing of NaCl aqueous solutions Open
Studying the freezing of saltwater on a molecular level is of fundamental importance for improving freeze desalination techniques.
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Compatibility of quantitative X-ray spectroscopy with continuous distribution models of water at ambient conditions Open
Significance Water is the matrix of life and behaves anomalously in many of its properties. Since Wilhelm Conrad Röntgen, two distinct separate phases have been argued to coexist in ambient water, competing with the alternative view of the…
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How Cubic Can Ice Be? Open
Using an X-ray laser, we investigated the crystal structure of ice formed by homogeneous ice nucleation in deeply supercooled water nanodrops (r ≈ 10 nm) at ∼225 K. The nanodrops were formed by condensation of vapor in a supersonic nozzle,…
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Molecular-Level Interpretation of Vibrational Spectra of Ordered Ice Phases Open
We build on results from our previous investigation into ice Ih using a combination of classical many-body molecular dynamics (MB-MD) and normal mode (NM) calculations to obtain molecular-level information on the spectroscopic signatures i…
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Mechanisms Underlying the Mpemba Effect in Water from Molecular Dynamics Simulations Open
Experimentally, quenching from warmer water leads to faster freezing than quenching from colder water—the Mpemba effect. Using molecular dynamics, we find that quenching water from 370 K and above leads to a 100 K density of states (DOS) c…
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Bulk moduli and equations of state of ice VII and ice VIII Open
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Melting Curve and Isostructural Solid Transition in Superionic Ice Open
The phase diagram and melting curve of water ice is investigated up to 45 GPa and 1600 K by synchrotron x-ray diffraction in the resistively and laser heated diamond anvil cell. Our melting data evidence a triple point at 14.6 GPa, 850 K. …
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A Chiral Gas–Hydrate Structure Common to the Carbon Dioxide–Water and Hydrogen–Water Systems Open
We present full in situ structural solutions of carbon dioxide hydrate-II and hydrogen hydrate C0 at elevated pressures using neutron and X-ray diffraction. We find both hydrates adopt a common water network structure. The structure exhibi…
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Melting points of water models: Current situation Open
By using the direct coexistence method, we have calculated the melting points of ice Ih at normal pressure for three recently proposed water models, namely, TIP3P-FB, TIP4P-FB, and TIP4P-D. We obtained Tm = 216 K for TIP3P-FB, Tm = 242 K f…
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Protein/Ice Interaction: High-Resolution Synchrotron X-ray Diffraction Differentiates Pharmaceutical Proteins from Lysozyme Open
Protein/ice interactions are investigated by a novel method based on measuring the characteristic features of X-ray diffraction (XRD) patterns of hexagonal ice (Ih). Aqueous solutions of four proteins and other solutes are studied using hi…
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Predicting the phase diagram of solid carbon dioxide at high pressure from first principles Open
The physics of solid carbon dioxide and its different polymorphs are not only of great practical and fundamental interest but also of considerable importance to terrestrial and planetary chemistry. Despite decades of computer simulations, …
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Structure and disorder in ice VII on the approach to hydrogen-bond symmetrization Open
We have collected neutron-diffraction data of sufficient quality for structural refinement from deuterated ice VII to over 60 GPa. At these pressures, we are approaching the onset of molecular dissociation where the water molecule should b…
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Reversible structural transition in nanoconfined ice Open
The report on square ice sandwiched between two graphene layers by Algara-Siller et al. [Nature (London) 519, 443 (2015)] has generated a large interest in this system. By applying high lateral pressure on nanoconfined water, we found that…
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Computational phase diagrams of noble gas hydrates under pressure Open
We present results from a first-principles study on the stability of noble gas-water compounds in the pressure range 0-100 kbar. Filled-ice structures based on the host water networks ice-Ih, ice-Ic, ice-II, and C0 interacting with guest s…
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Molecular Level Interpretation of Vibrational Spectra of Ordered Ice Phases Open
We build on results from our previous investigation into ice Ih using a combination of classical many-body molecular dynamics (MB-MD) and normal mode (NM) calculations to obtain molecular level information on the spectroscopic signature…
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Structures, dynamics, and hydrogen-bond interactions of antifreeze proteins in TIP4P/Ice water and their dependence on force fields Open
Tenebrio molitor antifreeze protein (TmAFP) was simulated with growing ice-water interfaces at a realistic melting temperature using TIP4P/Ice water model. To test compatibility of protein force fields (FFs) with TIP4P/Ice water, CHARMM, A…
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The vapor pressure over nano-crystalline ice Open
The crystallization of amorphous solid water (ASW) is known to form nano-crystalline ice. The influence of the nanoscale crystallite size on physical properties like the vapor pressure is relevant for processes in which the crystallization…
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Anomalous hydrogen dynamics of the ice VII–VIII transition revealed by high-pressure neutron diffraction Open
Above 2 GPa the phase diagram of water simplifies considerably and exhibits only two solid phases up to 60 GPa, ice VII and ice VIII. The two phases are related to each other by hydrogen ordering, with the oxygen sublattice being essential…
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Solid–liquid interfacial free energy of ice Ih, ice Ic, and ice 0 within a mono-atomic model of water via the capillary wave method Open
We apply the capillary wave method, based on measurements of fluctuations in a ribbon-like interfacial geometry, to determine the solid–liquid interfacial free energy for both polytypes of ice I and the recently proposed ice 0 within a mon…
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DMC-ICE13: Ambient and high pressure polymorphs of ice from diffusion Monte Carlo and density functional theory Open
Ice is one of the most important and interesting molecular crystals, exhibiting a rich and evolving phase diagram. Recent discoveries mean that there are now 20 distinct polymorphs; a structural diversity that arises from a delicate interp…