Tetrahedral structure or chains for liquid water

Head‐Gordon, Teresa; Johnson, Margaret E.

doi:10.1073/pnas.0510593103

Cited by 244 publications

(192 citation statements)

References 19 publications

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“…It has been suggested that a large fraction of molecules form only two strong HBs: one acceptor and one donor bond 2,152-156 . However, the"rings and chains" structure of liquid water 2 , as well as the inhomogeneous two-state model 152,157 implied by such an interpretation, have been challenged on many fronts 143,147,[158][159][160][161][162][163][164][165][166][167] and are a matter of an ongoing debate 80,143,147,[155][156][157][158][159][160][161][162][163][164][166][167][168][169][170][171][172] .…”

Section: Liquid Water a Structural And Dynamical Properties Of Lmentioning

confidence: 99%

Microscopic properties of liquid water from combined ab initio molecular dynamics and energy decomposition studies

Khaliullin

Kühne

2013

Phys. Chem. Chem. Phys.

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The application of newly developed first-principle modeling techniques to liquid water deepens our understanding of the microscopic origins of its unusual macroscopic properties and behaviour. Here, we review two novel ab initio computational methods: second-generation Car-Parrinello molecular dynamics and decomposition analysis based on absolutely localized molecular orbitals. We show that these two methods in combination not only enable ab initio molecular dynamics simulations on previously inaccessible time and length scales, but also provide unprecedented insights into the nature of hydrogen bonding between water molecules. We discuss recent applications of these methods to water clusters and bulk water. CONTENTS

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Section: Liquid Water a Structural And Dynamical Properties Of Lmentioning

confidence: 99%

Microscopic properties of liquid water from combined ab initio molecular dynamics and energy decomposition studies

Khaliullin

Kühne

2013

Phys. Chem. Chem. Phys.

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“…These experiments stirred a storm of controversy because of their interpretation suggesting that a large fraction (>80%) of H-bonds are broken in the liquid [2]. This would imply an environment consisting primarily of chains and rings of H-bonds, in stark contrast with the conventional near-tetrahedral picture supported by diffraction [3] and other thermodynamic and spectroscopic data [4,5]. The broken H-bond fraction was estimated from the intensity of the pre-edge, which is prominent in the liquid and was believed to be absent in bulk ice.…”

mentioning

confidence: 99%

X-Ray Absorption Signatures of the Molecular Environment in Water and Ice

2010

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The x-ray absorption spectra of water and ice are calculated with a many-body approach for electron-hole excitations. The experimental features, including the small effects of temperature change in the liquid, are quantitatively reproduced from molecular configurations generated by abinitio molecular dynamics. The spectral difference between the solid and the liquid is due to two major short range order effects. One, due to breaking of hydrogen bonds, enhances the pre-edge intensity in the liquid. The other, due to a non-bonded molecular fraction in the first coordination shell, affects the main spectral edge in the conversion of ice to water. This effect may not involve hydrogen bond breaking as shown by experiment in high-density amorphous ice.PACS numbers: 36.20. Ng, 71.15.Pd, 32.10.Dk, 78.20.Ci The nature of the hydrogen bond (H-bond) network in water continues to be at the center of scientific debate [1]. A few years ago high-resolution x-ray absorption spectra (XAS) probed the local order of liquid and crystalline water phases, including the effect of temperature in the liquid [2]. These experiments stirred a storm of controversy because of their interpretation suggesting that a large fraction (>80%) of H-bonds are broken in the liquid [2]. This would imply an environment consisting primarily of chains and rings of H-bonds, in stark contrast with the conventional near-tetrahedral picture supported by diffraction [3] and other thermodynamic and spectroscopic data [4,5]. The broken H-bond fraction was estimated from the intensity of the pre-edge, which is prominent in the liquid and was believed to be absent in bulk ice. Subsequent x-ray Raman spectra, however, showed that the pre-edge feature is present, albeit with different intensity, not only in the liquid, but also in hexagonal (Ih), cubic (Ic), low-density amorphous (LDA) and highdensity amorphous (HDA) ice [6]. This experiment reported another interesting observation, namely that water and HDA ice have spectra with the main-edge more prominent than the post-edge, while the opposite behavior occurs in Ih, Ic, and LDA ice. This is puzzling given that both LDA and HDA ice are disordered structures with an insignificant fraction of broken H-bonds. Spectral calculations, based on electronic density-functional theory (DFT) and near-tetrahedral liquid models, correctly predicted the presence of three spectral features in ice and water and associated the enhancement of the pre-edge intensity to broken H-bonds [7,8,9,10]. However, the agreement with experiment was only semiquantitative and the calculations did not identify the cause of the significant changes in main-and post-edge spectra. These effects were generically attributed to disorder [8], but this does not explain why LDA and HDA ice show opposite behavior [6]. Finally, no attempt was made to discuss the effect of temperature in the liquid spectra, for which contrasting experimental data have been reported [2,11,12,13].In this paper we use liquid structures generated by ab-initio MD to compute x-ra...

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“…Smith et al [55] used their total electron yield near-edge X-ray absorption time structure (TEY-NEXAFS) technique to come to very different conclusions: according to them, the water and ice H-bonds are very similar, and the usually accepted H-bond strength is consistent with their data. Also, according to Head-Gordon et al [56], the XAS data is most compatible with water as a tetrahedral hydrogen-bonded liquid. Tse et al [57] report on the X-ray absorption spectra of high-density amorphous (HDA) ice, low-density amorphous ice I c , ice I h , normal and deuterated liquid water by in situ heating of an HDA ice sample where they observed the previously reported distinct pre-edge structure in all spectra.…”

Section: Open Accessmentioning

confidence: 72%

“…However, the calculated field strength necessary in order to achieve such chains could are considerably higher than the ones applied in the water bridge experiment. Nevertheless, the existence of similar water chains (even without an external electric field) has been recently suggested [56].…”

Section: Quantum Mechanical/quantumelectrodynamical Viewpointmentioning

confidence: 99%

Can a Century Old Experiment Reveal Hidden Properties of Water?

Fuchs¹

2010

Water

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Abstract:In 1893 Sir William Armstrong placed a cotton thread between two wine glasses filled with chemically pure water. After applying a high voltage, a watery connection formed, and after some time, the cotton thread was pulled into one of the glasses, leaving a rope of water suspended between the two glasses. Although being a very simple experiment, it is of special interest since it comprises a number of phenomena currently tackled in modern water science like electrolysis-less charge transport and nanobubbles. This work gives some background information about water research in general and describes the water bridge phenomenon from the viewpoint of different fields such as electrohydrodynamics and quantum field theory. It is shown that the investigation of the floating water bridge led to new discoveries about water, both in the macroscopic and microscopic realm -but these were merely "hidden" in that sense that they only become evident upon application of electric fields.

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Tetrahedral structure or chains for liquid water

Cited by 244 publications

References 19 publications

Microscopic properties of liquid water from combined ab initio molecular dynamics and energy decomposition studies

Microscopic properties of liquid water from combined ab initio molecular dynamics and energy decomposition studies

X-Ray Absorption Signatures of the Molecular Environment in Water and Ice

Can a Century Old Experiment Reveal Hidden Properties of Water?

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