1
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de la Puente M, Laage D. Impact of interfacial curvature on molecular properties of aqueous interfaces. J Chem Phys 2024; 160:234504. [PMID: 38888129 DOI: 10.1063/5.0210884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 05/28/2024] [Indexed: 06/20/2024] Open
Abstract
The curvature of soft interfaces plays a crucial role in determining their mechanical and thermodynamic properties, both at macroscopic and microscopic scales. In the case of air/water interfaces, particular attention has recently focused on water microdroplets, due to their distinctive chemical reactivity. However, the specific impact of curvature on the molecular properties of interfacial water and interfacial reactivity has so far remained elusive. Here, we use molecular dynamics simulations to determine the effect of curvature on a broad range of structural, dynamical, and thermodynamical properties of the interface. For a droplet, a flat interface, and a cavity, we successively examine the structure of the hydrogen-bond network and its relation to vibrational spectroscopy, the dynamics of water translation, rotation, and hydrogen-bond exchanges, and the thermodynamics of ion solvation and ion-pair dissociation. Our simulations show that curvature predominantly impacts the hydrogen-bond structure through the fraction of dangling OH groups and the dynamics of interfacial water molecules. In contrast, curvature has a limited effect on solvation and ion-pair dissociation thermodynamics. For water microdroplets, this suggests that the curvature alone cannot fully account for the distinctive reactivity measured in these systems, which are of great importance for catalysis and atmospheric chemistry.
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Affiliation(s)
- M de la Puente
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - D Laage
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
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2
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Chiang KY, Yu X, Yu CC, Seki T, Sun S, Bonn M, Nagata Y. Bulklike Vibrational Coupling of Surface Water Revealed by Sum-Frequency Generation Spectroscopy. PHYSICAL REVIEW LETTERS 2023; 131:256202. [PMID: 38181372 DOI: 10.1103/physrevlett.131.256202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 10/10/2023] [Accepted: 10/30/2023] [Indexed: 01/07/2024]
Abstract
Vibrational coupling between interfacial water molecules is important for energy dissipation after on-water chemistry, yet intensely debated. Here, we quantify the interfacial vibrational coupling strength through the linewidth of surface-specific vibrational spectra of the water's O─H (O─D) stretch region for neat H_{2}O/D_{2}O and their isotopic mixtures. The local-field-effect-corrected experimental SFG spectra reveal that the vibrational coupling between hydrogen-bonded interfacial water O─H groups is comparable to that in bulk water, despite the effective density reduction at the interface.
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Affiliation(s)
- Kuo-Yang Chiang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Xiaoqing Yu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Chun-Chieh Yu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Takakazu Seki
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Shumei Sun
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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3
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Pandey PK, Chandra A. Mechanism, Kinetics, and Potential of Mean Force of Evaporation of Water from Aqueous Sodium Chloride Solutions of Varying Concentrations. J Phys Chem B 2023; 127:4602-4612. [PMID: 37163726 DOI: 10.1021/acs.jpcb.2c09004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The mechanism, kinetics, and potential of mean force of evaporation of water from aqueous NaCl solutions are investigated through both unbiased molecular dynamics simulations and also biased simulations using the umbrella sampling method. The results are obtained for aqueous solutions of three different NaCl concentrations ranging from 0.6 to 6.0 m and also for pure water. The rate of evaporation is found to decrease in the presence of ions. It is found that the process of evaporation of a surface water molecule from ionic solutions can be triggered through its collision with another water or chloride ion. Such collisions provide the additional kinetic energy that is required for evaporation. However, when the collision takes place with a Cl- ion, the evaporation of the escaping water also involves a collision with water in the vicinity of the ion at the same time along with the ion-water collision. These two collisions together provide the required kinetic energy for escape of the evaporating water molecule. Thus, the mechanism of evaporation process of ionic solutions can be more complex than that of pure water. The potential of mean force (PMF) of evaporation is found to be positive and it increases with increasing ion concentration. Also, no barrier in the PMF is found to be present for the condensation of water from vapor phase to the surfaces of the solutions. A detailed analysis of the unsuccessful evaporation attempts by surface water molecules is also made in the current study.
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Affiliation(s)
- Prashant Kumar Pandey
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, India 208016
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, India 208016
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4
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Bandyopadhyay D, Bhanja K, Choudhury N. On the Propensity of Excess Hydroxide Ions at the Alcohol Monolayer-Water Interface. J Phys Chem B 2023; 127:783-793. [PMID: 36639623 DOI: 10.1021/acs.jpcb.2c05719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Atomistic molecular dynamics simulations have been employed to study the self-ion (H+ and OH-) distribution at the interface between long-chain C16-OH alcohol (cetyl alcohol) monolayer and water. It is well known that the free air-water interface is acidic due to accumulation of the hydronium (H3O+) ions at the interface. In the present study, we have observed that contrary to the air-water interface, at the long-chain alcohol monolayer-water interface, it is the hydroxide (OH-) ion, not the hydronium ion (H3O+) that gets accumulated. By calculating the potential of mean forces, it is confirmed that there is extra stabilization for the OH- ions at the interface relative to the bulk, but no such stabilization is observed for the H3O+ ions. By analyzing the interaction of the self-ions with other constituents in the medium, it is clearly shown that the favorable interaction of the OH- ions with the alcoholic -OH groups stabilizes this ion at the interface. By calculating coordination numbers of the self-ions it is observed that around 50% water neighbors are substituted by alcoholic -OH in case of the hydroxide ion at the interface, whereas in the case of hydronium ions, only 15% water neighbors are substituted by the alcoholic -OH. The most interesting observation about the local structure and H-bonding pattern is that the hydroxide ion acts solely as the H-bond acceptor, but the hydronium ion acts only as the H-bond donor.
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Affiliation(s)
| | - Kalyan Bhanja
- Heavy Water Division, Bhabha Atomic Research Centre, Mumbai400 085, India
| | - Niharendu Choudhury
- Theoretical Chemistry Section, Chemistry Division, Bhabha Atomic Research Centre, Mumbai400 085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai400 094, India
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5
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The dielectric function profile across the water interface through surface-specific vibrational spectroscopy and simulations. Proc Natl Acad Sci U S A 2022; 119:e2204156119. [PMID: 36037357 PMCID: PMC9457560 DOI: 10.1073/pnas.2204156119] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dielectric properties of interfacial water on subnanometer length scales govern chemical reactions, carrier transfer, and ion transport at interfaces. Yet, the nature of the interfacial dielectric function has remained under debate as it is challenging to access the interfacial dielectric with subnanometer resolution. Here we use the vibrational response of interfacial water molecules probed using surface-specific sum-frequency generation (SFG) spectra to obtain exquisite depth resolution. Different responses originate from water molecules at different depths and report back on the local interfacial dielectric environment via their spectral amplitudes. From experimental and simulated SFG spectra at the air/water interface, we find that the interfacial dielectric constant changes drastically across an ∼1 Å thin interfacial water region. The strong gradient of the interfacial dielectric constant leads, at charged planar interfaces, to the formation of an electric triple layer that goes beyond the standard double-layer model.
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6
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Yu CC, Seki T, Chiang KY, Tang F, Sun S, Bonn M, Nagata Y. Polarization-Dependent Heterodyne-Detected Sum-Frequency Generation Spectroscopy as a Tool to Explore Surface Molecular Orientation and Ångström-Scale Depth Profiling. J Phys Chem B 2022; 126:6113-6124. [PMID: 35849538 PMCID: PMC9421650 DOI: 10.1021/acs.jpcb.2c02178] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Sum-frequency generation (SFG) spectroscopy provides
a unique optical
probe for interfacial molecules with interface-specificity and molecular
specificity. SFG measurements can be further carried out at different
polarization combinations, but the target of the polarization-dependent
SFG is conventionally limited to investigating the molecular orientation.
Here, we explore the possibility of polarization-dependent SFG (PD-SFG)
measurements with heterodyne detection (HD-PD-SFG). We stress that
HD-PD-SFG enables accurate determination of the peak amplitude, a
key factor of the PD-SFG data. Subsequently, we outline that HD-PD-SFG
can be used not only for estimating the molecular orientation but
also for investigating the interfacial dielectric profile and studying
the depth profile of molecules. We further illustrate the variety
of combined simulation and PD-SFG studies.
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Affiliation(s)
- Chun-Chieh Yu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Takakazu Seki
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Kuo-Yang Chiang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Fujie Tang
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Shumei Sun
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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7
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Odendahl NL, Geissler PL. Local Ice-like Structure at the Liquid Water Surface. J Am Chem Soc 2022; 144:11178-11188. [PMID: 35696525 DOI: 10.1021/jacs.2c01827] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Experiments and computer simulations have established that liquid water's surfaces can deviate in important ways from familiar bulk behavior. Even in the simplest case of an air-water interface, distinctive layering, orientational biases, and hydrogen bond arrangements have been reported, but an overarching picture of their origins and relationships has been incomplete. Here we show that a broad set of such observations can be understood through an analogy with the basal face of crystalline ice. Using simulations, we demonstrate a number of structural similarities between water and ice surfaces, suggesting the presence of domains at the air-water interface with ice-like features that persist over 2-3 molecular diameters. Most prominent is a shared characteristic layering of molecular density and orientation perpendicular to the interface. Lateral correlations of hydrogen bond network geometry point to structural similarities in the parallel direction as well. Our results bolster and significantly extend previous conceptions of ice-like structure at the liquid's boundary and suggest that the much-discussed quasi-liquid layer on ice evolves subtly above the melting point into a quasi-ice layer at the surface of liquid water.
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Affiliation(s)
- Nathan L Odendahl
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Phillip L Geissler
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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8
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Yu CC, Imoto S, Seki T, Chiang KY, Sun S, Bonn M, Nagata Y. Accurate molecular orientation at interfaces determined by multimode polarization-dependent heterodyne-detected sum-frequency generation spectroscopy via multidimensional orientational distribution function. J Chem Phys 2022; 156:094703. [DOI: 10.1063/5.0081209] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many essential processes occur at soft interfaces, from chemical reactions on aqueous aerosols in the atmosphere to biochemical recognition and binding at the surface of cell membranes. The spatial arrangement of molecules specifically at these interfaces is crucial for many of such processes. The accurate determination of the interfacial molecular orientation has been challenging due to the low number of molecules at interfaces and the ambiguity of their orientational distribution. Here, we combine phase- and polarization-resolved sum-frequency generation (SFG) spectroscopy to obtain the molecular orientation at the interface. We extend an exponentially decaying orientational distribution to multiple dimensions, which, in conjunction with multiple SFG datasets obtained from the different vibrational modes, allows us to determine the molecular orientation. We apply this new approach to formic acid molecules at the air–water interface. The inferred orientation of formic acid agrees very well with ab initio molecular dynamics data. The phase-resolved SFG multimode analysis scheme using the multidimensional orientational distribution thus provides a universal approach for obtaining the interfacial molecular orientation.
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Affiliation(s)
- Chun-Chieh Yu
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Sho Imoto
- Analysis Technology Center, Fujifilm R&D, 210 Nakanuma, Minamiashigara, Kanagawa 250-0123, Japan
| | - Takakazu Seki
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Kuo-Yang Chiang
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Shumei Sun
- Applied Optics Beijing Area Major Laboratory, Department of Physics, Beijing Normal University, 100875 Beijing, China
| | - Mischa Bonn
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Yuki Nagata
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
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9
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Shimoaka T, Fukumi A, Shioya N, Hasegawa T. Perfluoroalkanes remain on water surface even after volatilization: Affinity analysis of fluorinated solvent with water surface. J Colloid Interface Sci 2021; 611:390-396. [PMID: 34959011 DOI: 10.1016/j.jcis.2021.12.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 11/25/2022]
Abstract
Perfluoroalkyl (Rf) compounds are known to have a poor solubility for most solvents except fluorinated solvents, which is known as a fluorous property. In Langmuir (L) film studies of Rf compounds, fluorinated solvents such as perfluoro-n-alkanes are generally used as a good solvent for depositing a sample monolayer on the water surface. On the other hand, a single Rf chain with a short length such as C6F13- is known to exhibit a totally different character from a condensed matter to have a strong affinity to a water molecule on the water surface via the dipole-dipole interaction, which is known as the dipole interactive (DI) property. On considering the DI property, the solvents of perfluoro-n-alkanes would remain on water for a long time, which may disturb the formation of L film on water. In the present study, details of a liquid layer of perfluoro-n-alkanes on water are investigated by using infrared external reflection (IR ER) spectrometry. Although the perfluoro-n-alkanes are highly volatile, the relevant vibration bands did not disappear even after two hours, which means that they remain on the water surface. Fortunately, however, the remained solvent, C6F14, has been found no disturbing factor for preparation of L films.
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Affiliation(s)
- Takafumi Shimoaka
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
| | - Aki Fukumi
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Nobutaka Shioya
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takeshi Hasegawa
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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10
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Proteins maintain hydration at high [KCl] concentration regardless of content in acidic amino acids. Biophys J 2021; 120:2746-2762. [PMID: 34087206 PMCID: PMC8390907 DOI: 10.1016/j.bpj.2021.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/22/2021] [Accepted: 05/19/2021] [Indexed: 11/23/2022] Open
Abstract
Proteins of halophilic organisms, which accumulate molar concentrations of KCl in their cytoplasm, have a much higher content in acidic amino acids than proteins of mesophilic organisms. It has been proposed that this excess is necessary to maintain proteins hydrated in an environment with low water activity, either via direct interactions between water and the carboxylate groups of acidic amino acids or via cooperative interactions between acidic amino acids and hydrated cations. Our simulation study of five halophilic proteins and five mesophilic counterparts does not support either possibility. The simulations use the AMBER ff14SB force field with newly optimized Lennard-Jones parameters for the interactions between carboxylate groups and potassium ions. We find that proteins with a larger fraction of acidic amino acids indeed have higher hydration levels, as measured by the concentration of water in their hydration shell and the number of water/protein hydrogen bonds. However, the hydration level of each protein is identical at low (bKCl = 0.15 mol/kg) and high (bKCl = 2 mol/kg) KCl concentrations; excess acidic amino acids are clearly not necessary to maintain proteins hydrated at high salt concentration. It has also been proposed that cooperative interactions between acidic amino acids in halophilic proteins and hydrated cations stabilize the folded protein structure and would lead to slower dynamics of the solvation shell. We find that the translational dynamics of the solvation shell is barely distinguishable between halophilic and mesophilic proteins; if such a cooperative effect exists, it does not have that entropic signature.
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11
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Ishiyama T. Energy relaxation path of excited free OH vibration at an air/water interface revealed by nonequilibrium ab initio molecular dynamics simulation. J Chem Phys 2021; 154:104708. [PMID: 33722032 DOI: 10.1063/5.0038709] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nonequilibrium ab initio molecular dynamics (NE-AIMD) simulations are conducted at an air/water interface to elucidate the vibrational energy relaxation path of excited non-hydrogen-bonded (free) OH. A recent time-resolved vibrational sum frequency generation (TR-VSFG) spectroscopy experiment revealed that the relaxation time scales of free OH at the surface of pure water and isotopically diluted water are very similar to each other. In the present study, the dynamics of free OH excited at the surface of pure water and deuterated water are examined with an NE-AIMD simulation, which reproduces the experimentally observed features. The relaxation paths are examined by introducing constraints for the bonds and angles of water molecules relevant to specific vibrational modes in NE-AIMD simulations. In the case of free OH relaxation at the pure water surface, stretching vibrational coupling with the conjugate bond makes a significant contribution to the relaxation path. In the case of the isotopically diluted water surface, the bend (HOD)-stretching (OD) combination band couples with the free OH vibration, generating a relaxation rate similar to that in the pure water case. It is also found that the reorientation of the free OH bond contributes substantially to the relaxation of the free OH vibrational frequency component measured by TR-VSFG spectroscopy.
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Affiliation(s)
- Tatsuya Ishiyama
- Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan
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12
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Gordon BP, Lindquist GA, Crawford ML, Wren SN, Moore FG, Scatena LF, Richmond GL. Diol it up: The influence of NaCl on methylglyoxal surface adsorption and hydration state at the air–water interface. J Chem Phys 2020; 153:164705. [DOI: 10.1063/5.0017803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Brittany P. Gordon
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA
- Department of Chemistry, University of California, Irvine, 1214 Natural Sciences II, Irvine, California 92697, USA
| | - Grace A. Lindquist
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA
| | - Michael L. Crawford
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA
| | - Sumi N. Wren
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA
- Environment and Climate Change Canada (ECCC), Air Quality Research Division, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada
| | - Frederick G. Moore
- Department of Physics, Whitman College, Walla Walla, Washington 99362, USA
| | - Lawrence F. Scatena
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA
| | - Geraldine L. Richmond
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA
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13
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Ruiz-Lopez MF, Francisco JS, Martins-Costa MTC, Anglada JM. Molecular reactions at aqueous interfaces. Nat Rev Chem 2020; 4:459-475. [PMID: 37127962 DOI: 10.1038/s41570-020-0203-2] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2020] [Indexed: 12/16/2022]
Abstract
This Review aims to critically analyse the emerging field of chemical reactivity at aqueous interfaces. The subject has evolved rapidly since the discovery of the so-called 'on-water catalysis', alluding to the dramatic acceleration of reactions at the surface of water or at its interface with hydrophobic media. We review critical experimental studies in the fields of atmospheric and synthetic organic chemistry, as well as related research exploring the origins of life, to showcase the importance of this phenomenon. The physico-chemical aspects of these processes, such as the structure, dynamics and thermodynamics of adsorption and solvation processes at aqueous interfaces, are also discussed. We also present the basic theories intended to explain interface catalysis, followed by the results of advanced ab initio molecular-dynamics simulations. Although some topics addressed here have already been the focus of previous reviews, we aim at highlighting their interconnection across diverse disciplines, providing a common perspective that would help us to identify the most fundamental issues still incompletely understood in this fast-moving field.
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14
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Tang F, Ohto T, Sun S, Rouxel JR, Imoto S, Backus EHG, Mukamel S, Bonn M, Nagata Y. Molecular Structure and Modeling of Water-Air and Ice-Air Interfaces Monitored by Sum-Frequency Generation. Chem Rev 2020; 120:3633-3667. [PMID: 32141737 PMCID: PMC7181271 DOI: 10.1021/acs.chemrev.9b00512] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Indexed: 12/26/2022]
Abstract
From a glass of water to glaciers in Antarctica, water-air and ice-air interfaces are abundant on Earth. Molecular-level structure and dynamics at these interfaces are key for understanding many chemical/physical/atmospheric processes including the slipperiness of ice surfaces, the surface tension of water, and evaporation/sublimation of water. Sum-frequency generation (SFG) spectroscopy is a powerful tool to probe the molecular-level structure of these interfaces because SFG can specifically probe the topmost interfacial water molecules separately from the bulk and is sensitive to molecular conformation. Nevertheless, experimental SFG has several limitations. For example, SFG cannot provide information on the depth of the interface and how the orientation of the molecules varies with distance from the surface. By combining the SFG spectroscopy with simulation techniques, one can directly compare the experimental data with the simulated SFG spectra, allowing us to unveil the molecular-level structure of water-air and ice-air interfaces. Here, we present an overview of the different simulation protocols available for SFG spectra calculations. We systematically compare the SFG spectra computed with different approaches, revealing the advantages and disadvantages of the different methods. Furthermore, we account for the findings through combined SFG experiments and simulations and provide future challenges for SFG experiments and simulations at different aqueous interfaces.
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Affiliation(s)
- Fujie Tang
- Max
Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
- Department
of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Tatsuhiko Ohto
- Graduate
School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Shumei Sun
- Max
Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
- Department
of Physical Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
| | - Jérémy R. Rouxel
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Sho Imoto
- Max
Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Ellen H. G. Backus
- Max
Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
- Department
of Physical Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
| | - Shaul Mukamel
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Mischa Bonn
- Max
Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
| | - Yuki Nagata
- Max
Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
- Department
of Physics, State Key Laboratory of Surface Physics and Key Laboratory
of Micro- and Nano-Photonic Structures (MOE), Fudan University, Shanghai 200433, China
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15
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Ghaani MR, Kusalik PG, English NJ. Massive generation of metastable bulk nanobubbles in water by external electric fields. SCIENCE ADVANCES 2020; 6:eaaz0094. [PMID: 32284977 PMCID: PMC7124953 DOI: 10.1126/sciadv.aaz0094] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/26/2019] [Indexed: 05/21/2023]
Abstract
Nanobubbles (NBs) are nanoscopic gaseous domains than can exist on solid surfaces or in bulk liquids. They have attracted substantial attention due to their long-time (meta)stability and a high potential for real-world applications. Using an approach not previously investigated, we exploit surface-electrostatic NB formation and stabilization via application of external electric fields in gas-liquid systems, with the marked result of massively increased gas uptake into the liquid in NB form. The de facto gas solubility enhancement (over many months) ranges from 2.5-fold for oxygen to 30-fold for methane vis-à-vis respective Henry's law values for gas solubility; the more hydrophobic the gas, the more spectacular the increase. Molecular dynamics simulations reveal that the origin of NBs' movement lies in dielectrophoresis, while substantial NB stabilization arises from a surface-polarization interaction.
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Affiliation(s)
- Mohammad Reza Ghaani
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
- Corresponding author. (M.R.G.); (N.J.E.)
| | - Peter G. Kusalik
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
| | - Niall J. English
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
- Corresponding author. (M.R.G.); (N.J.E.)
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16
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Das S, Imoto S, Sun S, Nagata Y, Backus EHG, Bonn M. Nature of Excess Hydrated Proton at the Water-Air Interface. J Am Chem Soc 2020; 142:945-952. [PMID: 31867949 PMCID: PMC6966913 DOI: 10.1021/jacs.9b10807] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Indexed: 01/02/2023]
Abstract
Understanding the interfacial molecular structure of acidic aqueous solutions is important in the context of, e.g., atmospheric chemistry, biophysics, and electrochemistry. The hydration of the interfacial proton is necessarily different from that in the bulk, given the lower effective density of water at the interface, but has not yet been elucidated. Here, using surface-specific vibrational spectroscopy, we probe the response of interfacial protons at the water-air interface and reveal the interfacial proton continuum. Combined with spectral calculations based on ab initio molecular dynamics simulations, the proton at the water-air interface is shown to be well-hydrated, despite the limited availability of hydration water, with both Eigen and Zundel structures coexisting at the interface. Notwithstanding the interfacial hydrated proton exhibiting bulk-like structures, a substantial interfacial stabilization by -1.3 ± 0.2 kcal/mol is observed experimentally, in good agreement with our free energy calculations. The surface propensity of the proton can be attributed to the interaction between the hydrated proton and its counterion.
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Affiliation(s)
- Sudipta Das
- Department
for Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sho Imoto
- Department
for Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Shumei Sun
- Department
for Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department
of Physical Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
| | - Yuki Nagata
- Department
for Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Ellen H. G. Backus
- Department
for Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department
of Physical Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
| | - Mischa Bonn
- Department
for Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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17
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Boily JF, Fu L, Tuladhar A, Lu Z, Legg BA, Wang ZM, Wang H. Hydrogen bonding and molecular orientations across thin water films on sapphire. J Colloid Interface Sci 2019; 555:810-817. [PMID: 31425917 DOI: 10.1016/j.jcis.2019.08.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 01/28/2023]
Abstract
HYPOTHESIS Water vapor binding to metal oxide surfaces produces thin water films with properties controlled by interactions with surface hydroxo sites. Hydrogen bonding populations vary across films and induce different molecular orientations than at the surface of liquid water. Identifying these differences can open possibilities for tailoring film-mediated catalytic reactions by choice of the supporting metal oxide substrate. EXPERIMENTS The (0001) face of a single sapphire (α-Al2O3) sample exposed to water vapor and the surface of liquid water were probed by polarization dependent Sum Frequency Generation-Vibration Spectroscopy (SFG-VS). Molecular dynamics (MD) provided insight into the hydrogen bond populations and molecular orientations across films and liquid water. FINDINGS SFG-VS revealed a submonolayer film on sapphire exposed to 43% relative humidity (R.H.), and a multilayer film at 78% R.H. Polarization dependent SFG-VS spectra showed that median tilt angles of free OH bonds on the top of films are at ∼43° from the normal of the (0001) face but at 38° on neat liquid water. These values align with MD simulations, which also show that up to 36% of all OH bonds on films are free. This offers new means for understanding how interfacial reactions on sapphire-supported water films could contrast with those involving liquid water.
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Affiliation(s)
| | - Li Fu
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Aashish Tuladhar
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Zhou Lu
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Benjamin A Legg
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Zheming M Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Hongfei Wang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China
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18
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Gordon BP, Moore FG, Scatena LF, Richmond GL. On the Rise: Experimental and Computational Vibrational Sum Frequency Spectroscopy Studies of Pyruvic Acid and Its Surface-Active Oligomer Species at the Air–Water Interface. J Phys Chem A 2019; 123:10609-10619. [DOI: 10.1021/acs.jpca.9b08854] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Brittany P. Gordon
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, United States
| | - Frederick G. Moore
- Department of Physics, Whitman College, Walla Walla, Washington 99362, United States
| | - Lawrence F. Scatena
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, United States
| | - Geraldine L. Richmond
- Department of Chemistry, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, United States
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19
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Robalo JR, Streacker LM, Mendes de Oliveira D, Imhof P, Ben-Amotz D, Verde AV. Hydrophobic but Water-Friendly: Favorable Water–Perfluoromethyl Interactions Promote Hydration Shell Defects. J Am Chem Soc 2019; 141:15856-15868. [DOI: 10.1021/jacs.9b06862] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- João R. Robalo
- Department of Theory & Bio-systems, Max Planck Institute for Colloids and Interfaces, Science Park, Potsdam 14476, Germany
| | - Louis M. Streacker
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | | | - Petra Imhof
- Institute for Theoretical Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Dor Ben-Amotz
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ana Vila Verde
- Department of Theory & Bio-systems, Max Planck Institute for Colloids and Interfaces, Science Park, Potsdam 14476, Germany
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20
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Ohto T, Dodia M, Xu J, Imoto S, Tang F, Zysk F, Kühne TD, Shigeta Y, Bonn M, Wu X, Nagata Y. Accessing the Accuracy of Density Functional Theory through Structure and Dynamics of the Water-Air Interface. J Phys Chem Lett 2019; 10:4914-4919. [PMID: 31393136 PMCID: PMC6748669 DOI: 10.1021/acs.jpclett.9b01983] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 08/08/2019] [Indexed: 05/31/2023]
Abstract
Density functional theory-based molecular dynamics simulations are increasingly being used for simulating aqueous interfaces. Nonetheless, the choice of the appropriate density functional, critically affecting the outcome of the simulation, has remained arbitrary. Here, we assess the performance of various exchange-correlation (XC) functionals, based on the metrics relevant to sum-frequency generation spectroscopy. The structure and dynamics of water at the water-air interface are governed by heterogeneous intermolecular interactions, thereby providing a critical benchmark for XC functionals. We find that the XC functionals constrained by exact functional conditions (revPBE and revPBE0) with the dispersion correction show excellent performance. The poor performance of the empirically optimized density functional (M06-L) indicates the importance of satisfying the exact functional condition. Understanding the performance of different XC functionals can aid in resolving the controversial interpretation of the interfacial water structure and direct the design of novel, improved XC functionals better suited to describing the heterogeneous interactions in condensed phases.
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Affiliation(s)
- Tatsuhiko Ohto
- Graduate
School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Mayank Dodia
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Jianhang Xu
- Department
of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Sho Imoto
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Fujie Tang
- Department
of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Frederik Zysk
- Dynamics
of Condensed Matter and Center for Sustainable Systems Design, Chair
of Theoretical Chemistry, University of
Paderborn, Warburger Strasse 100, 33098 Paderborn, Germany
| | - Thomas D. Kühne
- Dynamics
of Condensed Matter and Center for Sustainable Systems Design, Chair
of Theoretical Chemistry, University of
Paderborn, Warburger Strasse 100, 33098 Paderborn, Germany
| | - Yasuteru Shigeta
- Graduate
School of Pure and Applied Sciences, University
of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8571, Japan
- Center
for Computational Sciences, University of
Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Mischa Bonn
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Xifan Wu
- Department
of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Yuki Nagata
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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21
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Dodia M, Ohto T, Imoto S, Nagata Y. Structure and Dynamics of Water at the Water-Air Interface Using First-Principles Molecular Dynamics Simulations. II. NonLocal vs Empirical van der Waals Corrections. J Chem Theory Comput 2019; 15:3836-3843. [PMID: 31074989 PMCID: PMC6750744 DOI: 10.1021/acs.jctc.9b00253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
![]()
van der Waals (vdW) correction schemes
have been recognized to
be essential for an accurate description of liquid water in first-principles
molecular dynamics simulation. The description of the structure and
dynamics of water is governed by the type of the vdW corrections.
So far, two vdW correction schemes have been often used: empirical
vdW corrections and nonlocal vdW corrections. In this paper, we assess
the influence of the empirical vs nonlocal vdW correction schemes
on the structure and dynamics of water at the water–air interface.
Since the structure of water at the water–air interface is
established by a delicate balance of hydrogen bond formation and breaking,
the simulation at the water–air interface provides a unique
platform to testify as to the heterogeneous interaction of water.
We used the metrics [Ohto et al. , 2019, 15, 595−60230468702] which
are directly connected with the sum-frequency generation spectroscopic
measurement. We find that the overall performance of nonlocal vdW
methods is either similar or worse compared to the empirical vdW methods.
We also investigated the performance of the optB88-DRSLL functional,
which showed slightly less accuracy than the revPBE-D3 method. We
conclude that the revPBE-D3 method shows the best performance for
describing the interfacial water.
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Affiliation(s)
- Mayank Dodia
- Max Planck Institute for Polymer Research, Ackermannweg 10 , 55128 Mainz , Germany
| | - Tatsuhiko Ohto
- Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama , Toyonaka, Osaka 560-8531 , Japan
| | - Sho Imoto
- Max Planck Institute for Polymer Research, Ackermannweg 10 , 55128 Mainz , Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, Ackermannweg 10 , 55128 Mainz , Germany
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22
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Xu X, Shen YR, Tian C. Phase-sensitive sum frequency vibrational spectroscopic study of air/water interfaces: H2O, D2O, and diluted isotopic mixtures. J Chem Phys 2019; 150:144701. [DOI: 10.1063/1.5081135] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Xiaofan Xu
- Department of Physics, State Key Laboratory of Surface Physics and Key Laboratory of Micro- and Nano-Photonic Structures (MOE), Fudan University, Shanghai 200433, China
| | - Y. Ron Shen
- Department of Physics, State Key Laboratory of Surface Physics and Key Laboratory of Micro- and Nano-Photonic Structures (MOE), Fudan University, Shanghai 200433, China
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Chuanshan Tian
- Department of Physics, State Key Laboratory of Surface Physics and Key Laboratory of Micro- and Nano-Photonic Structures (MOE), Fudan University, Shanghai 200433, China
- Department of Physics, University of California, Berkeley, California 94720, USA
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
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23
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Sun S, Tang F, Imoto S, Moberg DR, Ohto T, Paesani F, Bonn M, Backus EHG, Nagata Y. Orientational Distribution of Free O-H Groups of Interfacial Water is Exponential. PHYSICAL REVIEW LETTERS 2018; 121:246101. [PMID: 30608741 DOI: 10.1103/physrevlett.121.246101] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/09/2018] [Indexed: 06/09/2023]
Abstract
The orientational distribution of free O-H (O-D) groups at the H_{2}O- (D_{2}O-)air interface is investigated using combined molecular dynamics (MD) simulations and sum-frequency generation (SFG) experiments. The average angle of the free O-H groups, relative to the surface normal, is found to be ∼63°, substantially larger than previous estimates of 30°-40°. This discrepancy can be traced to erroneously assumed Gaussian or stepwise orientational distributions of free O-H groups. Instead, the MD simulation and SFG measurement reveal a broad and exponentially decaying orientational distribution. The broad orientational distribution indicates the presence of the free O-H group pointing down to the bulk. We ascribe the origin of such free O-H groups to the presence of capillary waves on the water surface.
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Affiliation(s)
- Shumei Sun
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Fujie Tang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- International Center for Quantum Materials, School of Physics, Peking University, 5 Yiheyuan Road, Haidian, Beijing 100871, China
| | - Sho Imoto
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Daniel R Moberg
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - Tatsuhiko Ohto
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Ellen H G Backus
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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24
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Ohto T, Dodia M, Imoto S, Nagata Y. Structure and Dynamics of Water at the Water–Air Interface Using First-Principles Molecular Dynamics Simulations within Generalized Gradient Approximation. J Chem Theory Comput 2018; 15:595-602. [DOI: 10.1021/acs.jctc.8b00567] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tatsuhiko Ohto
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Mayank Dodia
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sho Imoto
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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25
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Tang F, Ohto T, Hasegawa T, Xie WJ, Xu L, Bonn M, Nagata Y. Correction to Definition of Free O–H Groups of Water at the Air–Water Interface. J Chem Theory Comput 2018; 14:3363. [DOI: 10.1021/acs.jctc.8b00402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Ohto T, Tada H, Nagata Y. Structure and dynamics of water at water-graphene and water-hexagonal boron-nitride sheet interfaces revealed by ab initio sum-frequency generation spectroscopy. Phys Chem Chem Phys 2018; 20:12979-12985. [PMID: 29707716 DOI: 10.1039/c8cp01351a] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We simulate sum-frequency generation (SFG) spectra of isotopically diluted water at the water-graphene and water-hexagonal boron-nitride (hBN) sheet interfaces, using ab initio molecular dynamics simulations. A sharp 'dangling' O-D peak around ∼2640 cm-1 appearing in both simulated SFG spectra evidences that both graphene and hBN are hydrophobic. The dangling O-D peak is 10 cm-1 red-shifted at the water-hBN interface relative to the peak at the water-graphene interface. This frequency difference gives a stronger O-DN intermolecular interaction between water and hBN than the O-DC interaction between water and graphene. Accordingly, the anisotropy decay of such a dangling O-D group slows down near hBN compared with near graphene, illustrating that the dynamics of the dangling O-D group are also affected by the stronger O-DN interaction than the O-DC interaction. We discuss molecular-level insights into the structure and dynamics of interfacial water in the context of the friction of hBN and graphene.
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Affiliation(s)
- Tatsuhiko Ohto
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan.
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27
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Karmakar A, Chandra A. Water under Supercritical Conditions: Hydrogen Bonds, Polarity, and Vibrational Frequency Fluctuations from Ab Initio Simulations with a Dispersion Corrected Density Functional. ACS OMEGA 2018; 3:3453-3462. [PMID: 31458597 PMCID: PMC6641502 DOI: 10.1021/acsomega.7b02036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/09/2018] [Indexed: 05/27/2023]
Abstract
We have studied the effects of dispersion interactions on the dynamics of vibrational frequency fluctuations, hydrogen bonds, and free OD modes in supercritical heavy water at three different densities by means of ab initio molecular dynamics simulations. The vibrational spectral diffusion, as described by the frequency fluctuations, is studied through calculations of frequency time correlation of stretch modes of deuterated water, and its relations to the dynamics of hydrogen bonds and free OD modes are described. In addition, some of the other dynamical, structural, and electronic properties such as diffusion, rotational relaxation, radial distribution functions, hydrogen bond and coordination numbers, and dipole moments are also investigated from the perspectives of their variation with inclusion of dispersion interactions at varying density of the solvent. Although some changes in the structural properties are found on inclusion of dispersion corrections, no significant difference in the fluctuation dynamics of OD stretching frequencies and also in other dynamical quantities of supercritical water are found because of dispersion effects. The dynamics of water molecules under supercritical conditions is very fast compared to the corresponding dynamics under ambient conditions. The large thermal effects at such a high temperature seem to take over any relatively minor changes that might be introduced by weak dispersion interaction.
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