Anomalous Ground State of the Electrons in Nanoconfined Water

Reiter, George; Deb, Aniruddha; Sakurai, Y.; Itou, M.; Krishnan, Veena; Paddison, Stephen J.

doi:10.1103/physrevlett.111.036803

Cited by 67 publications

(48 citation statements)

References 24 publications

(25 reference statements)

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“…We anticipate that the routine inclusion of NQEs in ab initio simulations, which is made viable by these techniques, will contribute greatly to our future understanding of aqueous systems, including the solvation of the proton and its mobility in bulk water, in confinement (41,42), and at interfaces.…”

Section: Discussionmentioning

confidence: 99%

Nuclear quantum effects and hydrogen bond fluctuations in water

Ceriotti

Cuny

Parrinello

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

224

260

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The hydrogen bond (HB) is central to our understanding of the properties of water. However, despite intense theoretical and experimental study, it continues to hold some surprises. Here, we show from an analysis of ab initio simulations that take proper account of nuclear quantum effects that the hydrogen-bonded protons in liquid water experience significant excursions in the direction of the acceptor oxygen atoms. This generates a small but nonnegligible fraction of transient autoprotolysis events that are not seen in simulations with classical nuclei. These events are associated with major rearrangements of the electronic density, as revealed by an analysis of the computed Wannier centers and 1 H chemical shifts. We also show that the quantum fluctuations exhibit significant correlations across neighboring HBs, consistent with an ephemeral shuttling of protons along water wires. We end by suggesting possible implications for our understanding of how perturbations (solvated ions, interfaces, and confinement) might affect the HB network in water.path integral molecular dynamics | generalized Langevin equation thermostat | ab initio liquid water D espite its apparent simplicity, liquid water exhibits a number of anomalous properties, such as a decrease in density on freezing, an isobaric density maximum, and its unusually high dielectric constant and heat capacity (1). These, together with its unquestionable importance for climate and life on Earth, have made this substance a subject of intense research by both experiments and simulations.The central concept that has been used to rationalize the peculiar behavior of water is that of the hydrogen bond (HB) (2). The nature of this bond in water has been studied in depth by atomistic computer simulations, which have investigated how it is affected by ionic and electronic polarizability (3, 4), pressure and temperature (5, 6), and nuclear quantum effects (NQEs) (7-9). Furthermore, ab initio molecular dynamics (MD) simulations have been used to shed light on autoionization (10, 11), a process with profound implications for the chemistry of aqueous solutions.In this paper, we investigate the impact of NQEs on the HB in pure water, finding a qualitative increase in fluctuations that leads to a partial dissociation of the covalent O-H bond. The weakening of this covalent bond in the presence of hydrogen bonding is consistent with the red shift of the stretching mode of water upon condensation, as well as with recent experiments demonstrating that selectively exciting the O-H stretch in water leads to a pronounced delocalization of the proton toward the acceptor oxygen atom (12). However, the role of NQEs in governing the extent of this delocalization has not been investigated before now.Our analysis is based on MD simulations of water at different thermodynamic state points, with an ab initio description of the interactions among the nuclei. We also account fully for the quantum nature of the nuclear motion, using a recently developed combination of imaginary time path i...

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Section: Discussionmentioning

confidence: 99%

Nuclear quantum effects and hydrogen bond fluctuations in water

Ceriotti

Cuny

Parrinello

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

224

260

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“…For example, we described work that shows how calculated isotope effects vary significantly with 39 the DFT exchange-correlation functional that is used. This is because the potential energy surface, particularly with respect to the proton transfer co-ordinate, is quite sensitive to the oxygen-oxygen separation, and to the level of quantum chemical theory.…”

Section: Potential Energy Surfacesmentioning

confidence: 99%

“…These algorithmic advances have allowed simulations of liquid water with NQEs to be performed where the molecular interactions are computed using on-the-fly electronic structure calculations (5,(17)(18)(19)(20)(21)(22) and on potential energy surfaces fit to high-level ab initio calculations (23)(24)(25)(26)(27). In addition, experimental techniques such as deep inelastic neutron scattering (DINS) are now able to probe the proton and oxygen momentum distributions and quantum kinetic energies, providing intriguing new observations of these quantum properties of the nuclei at thermodynamic conditions ranging from supercooled to supercritical water, and environments ranging from the bulk to hydrophobic confinement (26,(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42).…”

Section: Introductionmentioning

confidence: 99%

Nuclear Quantum Effects in Water and Aqueous Systems: Experiment, Theory, and Current Challenges

et al. 2016

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Nuclear quantum effects influence the structure and dynamics of hydrogen bonded systems, such as water, which impacts their observed properties with widely varying magnitudes. This review highlights the recent significant developments in the experiment, theory and simulation of nuclear quantum effects in water. Novel experimental techniques, such as deep inelastic neutron scattering, now provide a detailed view of the role of nuclear quantum effects in water's 2 properties. These have been combined with theoretical developments such as the introduction of the competing quantum effects principle that allows the subtle interplay of water's quantum effects and their manifestation in experimental observables to be explained. We discuss how this principle has recently been used to explain the apparent dichotomy in water's isotope effects, which can range from very large to almost nonexistent depending on the property and conditions. We then review the latest major developments in simulation algorithms and theory that have enabled the efficient inclusion of nuclear quantum effects in molecular simulations, permitting their combination with on-the-fly evaluation of the potential energy surface using electronic structure theory. Finally, we identify current challenges and future opportunities in the area.3

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“…Саме такі фактори враховуються засобами квантової механіки. Група дослідників у лабораторії Rutherford Appleton Lab у Великобританії значну увагу приділяли вивченню квантових властивостей води у нанотрубках [5]. Специфіка експерименту полягала у вимірюванні параметрів водного середовища, обмеже-ного у просторі малих розмірів.…”

Section: аналіз літературних даних та постановка проблемиunclassified

Development of express-evaluation method of water biological properties

Глухова¹

2014

EEJET

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Anomalous Ground State of the Electrons in Nanoconfined Water

Cited by 67 publications

References 24 publications

Nuclear quantum effects and hydrogen bond fluctuations in water

Nuclear quantum effects and hydrogen bond fluctuations in water

Nuclear Quantum Effects in Water and Aqueous Systems: Experiment, Theory, and Current Challenges

Development of express-evaluation method of water biological properties

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