Zeidler<i>et al.</i>Reply:

Zeidler, Anita; Salmon, Philip S.; Fischer, Henry E.; Neuefeind, Jöerg C.; Simonson, J.M.; Lemmel, Hartmut; Rauch, H.; Markland, Thomas E.

doi:10.1103/physrevlett.108.259604

Cited by 17 publications

(47 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…239,240,244 Replication of the first O-O peak height reduction by using classical models requires an increase of the liquid temperature by DT C 35-40 K. By contrast, flexible anharmonic models and a recent first-principles molecular dynamics study predict much smaller changes in the structure of water, 220,240 corresponding to DT C 5-18 K. . 21,23 In (a) and (b) the vertical bars give the statistical errors on the measured data points and the solid (black) curves give spline fits that were used to generate the corresponding realspace functions shown in Fig. 18.…”

Section: Quantum Effects In the Hydrogen Bonded Network Of Watermentioning

confidence: 99%

“…The first-and second-difference functions were compared 21,23 to the results obtained from path integral molecular dynamics simulations 235 of light and heavy water using several different models of water, namely the rigid models TIP4P and SPC/E, 236,237 the flexible harmonic models SPC/F and qSPC/Fw, 238,239 and the flexible anharmonic models q-TIP4P/F and TTM3-F. 227,240 These calculations, in which a system of quantum mechanical particles is mapped onto a simulation of classical ring polymers, provide an exact treatment of nuclear quantum fluctuations in the structure of a given potential energy model for water. 235 In the cases of rigid or flexible harmonic classical models, the introduction of quantum effects leads, in general, to a large de-structuring of the hydrogen bonded network as shown by (i) a decrease in height of the first peak in g OO (r) which is an indicator of inter-molecular ordering, and (ii) an increase in the number of hydrogen bonds broken.…”

Section: Quantum Effects In the Hydrogen Bonded Network Of Watermentioning

confidence: 99%

“…Recent work includes the development of suitable protocols to measure (i) the structure of single droplets of liquid oxides at hightemperatures (B2000 K) by using the containerless aerodynamiclevitation with laser-heating method, 18,19 (ii) the structure of glass at high-pressures in the range from ambient to B8 GPa by employing a Paris-Edinburgh press, 20 and (iii) the structure of light versus heavy water by using the method of oxygen NDIS where there is a small contrast between the measured diffraction patterns for different isotopically enriched samples. [21][22][23] The aim of all of these NDIS experiments is to provide benchmark results to test whether the various theoretical schemes, which need to be employed in the development of accurate predictive models for different classes of materials, contain the right ingredients. For example, how best can transferrable potentials be constructed for use in classical molecular dynamics simulations, [24][25][26][27][28] and what is the best density functional to use for a given system in first-principles molecular dynamics simulations?…”

mentioning

confidence: 99%

“…**** The principal peak in the measured neutron diffraction pattern for liquid ammonia also sharpens with increasing density as packing constraints become more important. 192 The extended-range ordering for this system is described by using eqn (21).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Identifying and characterising the different structural length scales in liquids and glasses: an experimental approach

Salmon

Zeidler

2013

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

The structure of several network-forming liquids and glasses is considered, where a focus is placed on the detailed information that is made available by using the method of neutron diffraction with isotope substitution (NDIS). In the case of binary network glass-forming materials with the MX 2 stoichiometry (e.g. GeO 2 , GeSe 2 , ZnCl 2 ), two different length scales at distances greater than the nearest-neighbour distance manifest themselves by peaks in the measured diffraction patterns. The network properties are influenced by a competition between the ordering on these ''intermediate'' and ''extended'' length scales, which can be manipulated by changing the chemical identity of the atomic constituents or by varying state parameters such as the temperature and pressure. The extended-range ordering, which describes the decay of the pair-correlation functions at large-r, can be represented by making a pole analysis of the Ornstein-Zernike equations, an approach that can also be used to describe the large-r behaviour of the pair-correlation functions for liquid and amorphous metals where packing constraints are important. The first applications are then described of the NDIS method to measure the detailed structure of aerodynamically-levitated laser-heated droplets of ''fragile'' glass-forming liquid oxides (CaAl 2 O 4 and CaSiO 3 ) at high-temperatures (B2000 K) and the structure of a ''strong'' network-forming glass (GeO 2 ) under pressures ranging from ambient to B8 GPa. The high-temperature experiments show structural changes on multiple length scales when the oxides are vitrified. The high-pressure experiment offers insight into the density-driven mechanisms of network collapse in GeO 2 glass, and parallels are drawn with the high-pressure behaviour of silica glass. Finally, the hydrogen-bonded network of water is considered, where the first application of the method of oxygen NDIS is used to measure the structures of light versus heavy water and a difference of C0.5% is found between the O-D and O-H intra-molecular bond lengths. The experimental data are best matched by using path integral molecular dynamics simulations with a flexible anharmonic water model, and the results support a competing quantum effects model for water in which its structural and dynamical properties are governed by an offset between intra-molecular and inter-molecular quantum contributions.

show abstract

Section: Quantum Effects In the Hydrogen Bonded Network Of Watermentioning

confidence: 99%

Section: Quantum Effects In the Hydrogen Bonded Network Of Watermentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Identifying and characterising the different structural length scales in liquids and glasses: an experimental approach

Salmon

Zeidler

2013

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Our theoretical modeling explains these anomalies, and allows us to predict and to experimentally confirm a counter effect, namely that replacement of 16 O by 18 O causes a normal lattice contraction. Numerous recent studies [1][2][3][4][5][6][7] address the contribution of zero-point nuclear quantum effects to the structures of ice and water. The issue is delicate, because of the peculiar electrostatic-covalent nature [8] of the hydrogen bond (Hbond) in water.…”

mentioning

confidence: 99%

Anomalous Nuclear Quantum Effects in Ice

et al. 2012

View full text Add to dashboard Cite

One striking anomaly of water ice has been largely neglected and never explained. Replacing hydrogen ( 1 H) by deuterium ( 2 H) causes ice to expand, whereas the "normal" isotope effect is volume contraction with increased mass. Furthermore, the anomaly increases with temperature T , even though a normal isotope shift should decrease with T and vanish when T is high enough to use classical nuclear motions. In this study, we show that these effects are very well described by ab initio density functional theory. Our theoretical modeling explains these anomalies, and allows us to predict and to experimentally confirm a counter effect, namely that replacement of 16 =0 [15]. This "normal" isotope effect corresponds to a ∼12% zero-point expansion of 20 Ne relative to a hypothetical "classical" or "frozen" lattice [16,17]. Since H 2 O and Ne have similar molecular masses, one might expect similar effects. However, the volume of H 2 O at T = 0 is ∼0.1% smaller than that of D 2 O [12,13]. It has rarely been mentioned in the literature that this is opposite to the usual behavior, and no explanation has been offered.In this paper, we explain this effect as an interesting coupling between quantum nuclear motion and hydrogen bonding, that may be relevant also to the structure of liquid water. Our analysis shows that, despite the anomalous isotope effect, quantum ice actually has a volume 1% larger than it would have with classical nuclei. The effects are smaller than in Ne mostly because of delicate cancellations. We exploit these cancellations to make critical comparisons of: (i) quasiharmonic theory versus fully anharmonic path-integral molecular dynamics (PIMD); (ii) ab initio forces versus flexible and polarizable empirical force fields (EFF); and (iii) various flavors of ab initio density-functional theory (DFT) exchange and correlation (XC) density functionals (DF) with and without inclusion of van der Waals (vdW) interactions. We find: (i) quasiharmonic theory is satisfactory for this problem; (ii) present state of the art EFFs are not good enough to describe nuclear quantum effects in water; and (iii) all the DFs considered describe qualitatively the anomalous effects, although some versions perform better than others.Within the volume-dependent quasiharmonic approximation (QHA), the equilibrium volume V (T ) is obtained by minimizing at each T the Helmholtz free energy F (V, T ) [18,19]:where E 0 (V ) is the energy for classical (T = 0 or frozen) nuclei, at the relaxed atomic coordinates for each volume. ω k are the phonon frequencies, with k combining the branch index and the phonon wave vector within the Brillouin zone. Their volume dependence is linearized as:whereis the Grüneisen parameter of the mode, and V 0 is the equilibrium volume of E 0 (V ). ω k (V 0 ) and γ k (V 0 ) are obtained by diagonalizing the dynamical matrix, computed by finite differences from the atomic forces in a (3 × 3 × 3) supercell, at two volumes slightly below and above V 0 . As shown in the supplementary information [20] (SI), this li...

show abstract

Switching of hydrogen bonds of water in ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate

Yoshimura

Takekiyo

Okamoto

et al. 2013

J Raman Spectroscopy

View full text Add to dashboard Cite

We have investigated temperature‐induced Raman spectral changes of deuterated water in an ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim][BF4]), between room temperature and 77 K. The comparison of the OH and OD stretching vibrational spectra at 77 K shows that the strength of the hydrogen bonds in [bmim][BF4]–water mixtures strongly depends on the type of water, i.e. H2O and D2O. In the [bmim][BF4]–D2O system, remarkably strong hydrogen bonds form at low temperatures, but they switch to nearly free hydrogen bonds on heating. Copyright © 2013 John Wiley & Sons, Ltd.

show abstract

Zeidleret al.Reply:

Cited by 17 publications

References 10 publications

Identifying and characterising the different structural length scales in liquids and glasses: an experimental approach

Identifying and characterising the different structural length scales in liquids and glasses: an experimental approach

Anomalous Nuclear Quantum Effects in Ice

Switching of hydrogen bonds of water in ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate

Contact Info

Product

Resources

About