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Ren A, Lu D, Wong E, Hauwiller MR, Alivisatos AP, Ren G. Real-time observation of dynamic structure of liquid-vapor interface at nanometer resolution in electron irradiated sodium chloride crystals. Sci Rep 2020; 10:8596. [PMID: 32451405 PMCID: PMC7248077 DOI: 10.1038/s41598-020-65274-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 04/30/2020] [Indexed: 01/29/2023] Open
Abstract
The dynamics and structure of the liquid and vapor interface has remained elusive for decades due to the lack of an effective tool for directly visualization beyond micrometer resolution. Here, we designed a simple liquid-cell for encapsulating the liquid state of sodium for transmission electron microscopic (TEM) observation. The real-time dynamic structure of the liquid-vapor interface was imaged and videoed by TEM on the sample of electron irradiated sodium chloride (NaCl) crystals, a well-studied sample with low melting temperature and quantum super-shells of clusters. The nanometer resolution images exhibit the fine structures of the capillary waves, composed of first-time observed three zones of structures and features, i.e. flexible nanoscale fibers, nanoparticles/clusters, and a low-pressure area that sucks the nanoparticles from the liquid to the interface. Although the phenomenons were observed based on irradiated NaCl crystals, the similarities of the phenomenons to predictions suggest our real-time ovserved dynamic structure might be useful in validating long-debated theoretical models of the liquid-vapor interface, and enhancing our knowledge in understanding the non-equilibrium thermodynamics of the liquid-vapor interface to benefit future engineering designs in microfluidics.
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Affiliation(s)
- Amy Ren
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- The Department of Physics, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - David Lu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- The Department of Chemistry, Brown University, Providence, RI, 02912, USA
| | - Edward Wong
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Matthew R Hauwiller
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Department of Materials Science, University of California, Berkeley, CA, 94720, USA
- Kavli Energy NanoScience Institute, University of California, Berkeley, CA, 94720, USA
| | - A Paul Alivisatos
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Department of Materials Science, University of California, Berkeley, CA, 94720, USA
- Kavli Energy NanoScience Institute, University of California, Berkeley, CA, 94720, USA
| | - Gang Ren
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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Desmaele E, Sator N, Vuilleumier R, Guillot B. Atomistic simulations of molten carbonates: Thermodynamic and transport properties of the Li 2CO 3-Na 2CO 3-K 2CO 3 system. J Chem Phys 2019; 150:094504. [PMID: 30849908 DOI: 10.1063/1.5082731] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Although molten carbonates only represent, at most, a very minor phase in the Earth's mantle, they are thought to be implied in anomalous high-conductivity zones in its upper part (70-350 km). Besides, the high electrical conductivity of these molten salts is also exploitable in fuel cells. Here, we report quantitative calculations of their properties, over a large range of thermodynamic conditions and chemical compositions, which are a requisite to develop technological devices and to provide a better understanding of a number of geochemical processes. To model molten carbonates by atomistic simulations, we have developed an optimized classical force field based on experimental data of the literature and on the liquid structure issued from ab initio molecular dynamics simulations performed by ourselves. In implementing this force field into a molecular dynamics simulation code, we have evaluated the thermodynamics (equation of state and surface tension), the microscopic liquid structure and the transport properties (diffusion coefficients, electrical conductivity, and viscosity) of molten alkali carbonates (Li2CO3, Na2CO3, K2CO3, and some of their binary and ternary mixtures) from the melting point up to the thermodynamic conditions prevailing in the Earth's upper mantle (∼1100-2100 K, 0-15 GPa). Our results are in very good agreement with the data available in the literature. To our knowledge, a reliable molecular model for molten alkali carbonates covering such a large domain of thermodynamic conditions, chemical compositions, and physicochemical properties has never been published yet.
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Affiliation(s)
- Elsa Desmaele
- Sorbonne Université, CNRS, Laboratoire de Physique Théorique de la Matière Condensée, LPTMC, F75005 Paris, France
| | - Nicolas Sator
- Sorbonne Université, CNRS, Laboratoire de Physique Théorique de la Matière Condensée, LPTMC, F75005 Paris, France
| | - Rodolphe Vuilleumier
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Bertrand Guillot
- Sorbonne Université, CNRS, Laboratoire de Physique Théorique de la Matière Condensée, LPTMC, F75005 Paris, France
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Lindenberg EK, Patey GN. Melting point trends and solid phase behaviors of model salts with ion size asymmetry and distributed cation charge. J Chem Phys 2015; 143:024508. [DOI: 10.1063/1.4923344] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- E. K. Lindenberg
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - G. N. Patey
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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Ghatee MH, Zolghadr AR, Moosavi F, Pakdel L. The extent of molecular orientation at liquid/vapor interface of pyridine and its alkyl derivatives by molecular dynamics simulation. J Chem Phys 2011; 134:074707. [DOI: 10.1063/1.3554361] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rollet AL, Salanne M. Studies of the local structures of molten metal halides. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1pc90003j] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Galamba N. Molecular dynamics study of the vaporization of an ionic drop. J Chem Phys 2010; 133:124510. [DOI: 10.1063/1.3483897] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Vatamanu J, Borodin O, Smith GD. Molecular dynamics simulations of atomically flat and nanoporous electrodes with a molten salt electrolyte. Phys Chem Chem Phys 2010; 12:170-82. [DOI: 10.1039/b917592j] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Affiliation(s)
- R. M. LYNDEN-BELL
- a Atomistic Simulation Group, School of Mathematics and Physics , Queen's University , Belfast , BT7 1NN , UK
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Lamperski S, Kłos J. Grand canonical Monte Carlo investigations of electrical double layer in molten salts. J Chem Phys 2008; 129:164503. [DOI: 10.1063/1.2933434] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Molecular dynamics simulations are used to investigate the low-temperature structures and temperature-driven rearrangements of (LiCl)n clusters, with n ranging from 3 to 500. It is found that for n < or = 32 expanded, ring-based structures are energetically more stable than cubic (rocksalt) forms at low temperature. For n > or = 108, the cubic structures are lower in energy, but as the clusters are heated rearrangements to expanded structures occur well below the melting temperature. Hexagonal (LiCl)3 rings are a distinguishing feature of the expanded, ring-based structures. Highly asymmetric ion sizes are essential for the formation of the expanded structures. Similar transitions from more-ordered to less-ordered solid states are not found for corresponding (KCl)n clusters, which remain in the cubic structure until they melt.
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Affiliation(s)
- T Croteau
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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Sloutskin E, Lynden-Bell RM, Balasubramanian S, Deutsch M. The surface structure of ionic liquids: Comparing simulations with x-ray measurements. J Chem Phys 2006; 125:174715. [PMID: 17100469 DOI: 10.1063/1.2361289] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The surface-normal electron density profile of an ionic liquid, [bmim][PF6], derived from x-ray reflectivity measurements, is compared with two independent molecular-dynamics simulations. It is shown that a meaningful comparison requires a detailed accounting for both thermal and nonthermal surface roughening effects. The former is due to thermally excited capillary waves, and the latter is due to the molecular zero-point motion and form. These quantities influence very significantly, but differently, the simulated and measured density profiles. Stripping off these effects from both types of profiles yields the intrinsic structure factor of the surface. The simulated intrinsic structure factors are found to deviate considerably from the measured one. The introduction of additional ad hoc surface roughness to the simulated profiles greatly reduces the deviation, however, no physical origin for this effect can be identified. The method employed in this study should prove useful for simulation-experiment comparisons of other liquid surfaces, provided they obey capillary-wave theory, as do almost all liquid surfaces studied to date by x-ray reflectivity.
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Affiliation(s)
- E Sloutskin
- Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel
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Yan T, Li S, Jiang W, Gao X, Xiang B, Voth GA. Structure of the Liquid−Vacuum Interface of Room-Temperature Ionic Liquids: A Molecular Dynamics Study. J Phys Chem B 2006; 110:1800-6. [PMID: 16471748 DOI: 10.1021/jp055890p] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular dynamics simulations for the liquid-vacuum interface of the ionic liquid 1-ethyl-3-methylimidazolium nitrate (EMIM+/NO3-) were performed for both electronically polarizable and nonpolarizable potential energy surfaces. The interfacial structural properties, such as the oscillation in the number density profile, the orientational ordering, and the local clustering in the interfacial region, were calculated. The simulations with both the polarizable and nonpolarizable model demonstrate the existence of an inhomogeneous interfacial structure normal to the surface layer. It was found for both models that the ethyl tail group on EMIM+ is likely to protrude outward from the surface. In the outmost surface layer, the cation is likely to lie on the surface with the imidazolium ring parallel to the interface, while there is a second region with enhanced density from that in the bulk where the cation preferably slants with the imidazolium ring tending to be perpendicular to the surface. The results also reveal that the electronic polarization effect is important for the ionic liquid interface. It is found that the cation is likely to be segregated at the ionic liquid surface for the polarizable model, while for the nonpolarizable model, the anion is found to be more likely to exhibit such behavior. The surface tension of the polarizable model (58.5 +/- 0.5 mN/m) is much smaller than that of the nonpolarizable model (82.7 +/- 0.6 mN/m), in better agreement with extrapolated experimental measurements on similar ionic liquid systems.
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Affiliation(s)
- Tianying Yan
- Institute of New Energy Material Chemistry and Department of Material Chemistry, Nankai University, Tianjin 300071, China
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Lynden-Bell RM, Del Pópolo M. Simulation of the surface structure of butylmethylimidazolium ionic liquids. Phys Chem Chem Phys 2006; 8:949-54. [PMID: 16482337 DOI: 10.1039/b514848k] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular dynamics simulations of the liquid/vacuum surfaces of the room temperature ionic liquids [bmim][PF(6)], [bmim][BF(4)] and [bmim][Cl] have been carried out at various temperatures. The surfaces are structured with a top monolayer containing oriented cations and anions. The butyl side chains tend to face the vacuum and the methyl side chains the liquid. However, as the butyl chains are not densely packed, both anions and rings are visible from the vacuum phase. The effects of temperature and the anion on the degree of cation orientation is small, but the potential drop from the vacuum to the interior of the liquid is greater for liquids with smaller anions. We compare the simulation results with a range of experimental observations and suggest that neutron reflection from samples with protiated butyl groups would be a sensitive probe of the structure.
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Affiliation(s)
- R M Lynden-Bell
- University Chemical Laboratory, Lensfield Road, Cambridge, UK CB2 1EW.
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Lanning OJ, Shellswell S, Madden * PA. Solid–liquid coexistence in ionic systems and the properties of the interface. Mol Phys 2004. [DOI: 10.1080/00268970410001689621] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Aguado A, Madden PA. Ewald summation of electrostatic multipole interactions up to the quadrupolar level. J Chem Phys 2003. [DOI: 10.1063/1.1605941] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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