scholarly journals The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

2021 ◽  
Author(s):  
Victor Kwan ◽  
Ryan O'Dwyer ◽  
David Laur ◽  
Jiahua Tan ◽  
Styliani Consta
Keyword(s):  
Chemical Reactivity ◽  
Double Electric Layer ◽  
Atomistic Simulations ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Ion Distribution ◽  
Equilibrium Partition ◽  
Equilibrium Process ◽  
Ejection Mechanism ◽  
Ion Evaporation

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results are consistent with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

scholarly journals The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

2021 ◽  
Author(s):  
Victor Kwan ◽  
Ryan O'Dwyer ◽  
David Laur ◽  
Jiahua Tan ◽  
Styliani Consta
Keyword(s):  
Chemical Reactivity ◽  
Double Electric Layer ◽  
Atomistic Simulations ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Ion Distribution ◽  
Equilibrium Partition ◽  
Equilibrium Process ◽  
Ejection Mechanism ◽  
Ion Evaporation

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results agree with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

scholarly journals The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

2021 ◽  
Author(s):  
Victor Kwan ◽  
Ryan O'Dwyer ◽  
David Laur ◽  
Jiahua Tan ◽  
Styliani Consta
Keyword(s):  
Chemical Reactivity ◽  
Double Electric Layer ◽  
Atomistic Simulations ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Ion Distribution ◽  
Equilibrium Partition ◽  
Equilibrium Process ◽  
Ejection Mechanism ◽  
Ion Evaporation

The composition of outer drop layers has been associated with distinct chemical reactivity. We use atomistic modeling to examine how the composition of the surface excess charge layer (SECL) is related to the ejection mechanisms of ions. Even though the drop disintegration is inherently a non-equilibrium process we find that the equilibrium ion distribution in SECL predicts the ions that are ejected. The escape of the ions in aqueous drops takes place from conical protrusions that are global drop deformations and their appearance is independent of the location of a single ion. Our results are consistent with the equilibrium partition model, which associates the mass spectrum with the distribution of analytes in the drop’s double electric layer. We present evidence that atomistic simulations of minute nano-drops cannot distinguish Rayleigh fission from the ion evaporation mechanism.

scholarly journals Atomistic Modeling Of Co Growth On Cu(111)

2001 ◽  
Vol 696 ◽  
Author(s):  
Joseph Khalil ◽  
Guillermo Bozzolo ◽  
Daniel Farías ◽  
A.L. Vázquez de Parga ◽  
J.J. de Miguel ◽  
...  
Keyword(s):  
First Principles ◽  
Atomistic Simulations ◽  
Atomistic Modeling ◽  
First Principles Calculations ◽  
Low Coverage

AbstractThe BFS method for alloys is applied to the study of Co growth on Cu(111). The parameterization of the Co-Cu system is obtained from first-principles calculations, and tested against known experimental features for low coverage Co deposition on Cu(100) and Cu(111). Atomistic simulations are performed to investigate the behavior of Co on Cu(111) as a function of coverage.

scholarly journals Effect of Droplet Size and Counterions on the Spatial Distribution of Ions

2020 ◽  
Author(s):  
Victor Kwan ◽  
Styliani Consta
Keyword(s):  
Charge Carriers ◽  
Spatial Distributions ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Surface Excess ◽  
Ion Distributions ◽  
Charged Droplets ◽  
Droplet Sizes ◽  
Simulation Results ◽  
First Time

<div>Charged droplets have become a new environment for accelerating chemical reactions by orders of magnitude relative to their bulk analogues. Nevertheless the reaction mechanisms still remain unknown. Here we investigate the ion spatial distributions and surface charge in aqueous droplets with diameters in the range of 5 nm to 16 nm with and without counterions using molecular dynamics. The charge carriers are Na, and Cl ions ions. We demonstrate the convergence of ion spatial distributions. Scaling of the ion distributions reveals underlying universal behavior. The convergence allows one to extrapolate the simulation results from nanoscopic dimensions to larger ones, which are still inaccessible to atomistic modeling.</div><div>The surface excess charge and electric field are also computed. We find that the surface excess charge layer in the presence of Na and Cl ions is approximately 1.5 nm-1.7 nm thick and that approximately 55%-33 % (from smaller to larger droplets) of the total number of ions reside in this layer. For the first time droplet sizes that are accessible to experimental scrutiny are modeled atomistically. </div>

scholarly journals The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

2021 ◽  
Author(s):  
Victor Kwan ◽  
Ryan O'Dwyer ◽  
David Laur ◽  
Jiahua Tan ◽  
Styliani Consta
Keyword(s):  
Surface Layer ◽  
Chemical Reactivity ◽  
Critical Role ◽  
Reaction Rates ◽  
Mass Spectrometry Data ◽  
Charged Droplet ◽  
Droplet Deformation ◽  
Ion Evaporation ◽  
Dynamics Simulations ◽  
Evaporation Mechanism

<div> Charged droplets have been associated with distinct chemical reactivity. It is assumed that the composition of the surface layer plays a critical role in enhancing the reaction rates in the droplets relative to their bulk counterparts. We use atomistic modeling to relate the localization of the ions in the surface layer to their ejection propensity. We find that<br>the ion ejection takes place via a two-stage process. Firstly, a conical protrusion emerges as a result of a global droplet deformation that is insensitive to the locations of single ions. The ions are subsequently ejected as they enter the conical regions. The study provides mechanistic insight into the<br> ion-evaporation mechanism, which can be used to revise the commonly used ion-evaporation models. We argue that atomistic molecular dynamics simulations of minute nano-drops, do not sufficiently distinguish the ion-evaporation mechanism from a Rayleigh fission. We explain mass spectrometry data on the charge state of small globular proteins and the existence of super-charged droplet states (above the Rayleigh limit) that have been detected in experiments. <br></div><div><br></div><div><br></div><div><br></div>

Effect of Droplet Size and Counterions on the Spatial Distribution of Ions

2020 ◽  
Author(s):  
Victor Kwan ◽  
Styliani Consta
Keyword(s):  
Charge Carriers ◽  
Spatial Distributions ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Surface Excess ◽  
Ion Distributions ◽  
Charged Droplets ◽  
Droplet Sizes ◽  
Simulation Results ◽  
First Time

<div>Charged droplets have become a new environment for accelerating chemical reactions by orders of magnitude relative to their bulk analogues. Nevertheless the reaction mechanisms still remain unknown. Here we investigate the ion spatial distributions and surface charge in aqueous droplets with diameters in the range of 5 nm to 16 nm with and without counterions using molecular dynamics. The charge carriers are Na, and Cl ions ions. We demonstrate the convergence of ion spatial distributions. Scaling of the ion distributions reveals underlying universal behavior. The convergence allows one to extrapolate the simulation results from nanoscopic dimensions to larger ones, which are still inaccessible to atomistic modeling.</div><div>The surface excess charge and electric field are also computed. We find that the surface excess charge layer in the presence of Na and Cl ions is approximately 1.5 nm-1.7 nm thick and that approximately 55%-33 % (from smaller to larger droplets) of the total number of ions reside in this layer. For the first time droplet sizes that are accessible to experimental scrutiny are modeled atomistically. </div>

Effect of Droplet Size and Counterions on the Spatial Distribution of Ions

2020 ◽  
Author(s):  
Victor Kwan ◽  
Styliani Consta
Keyword(s):  
Charge Carriers ◽  
Spatial Distributions ◽  
Excess Charge ◽  
Atomistic Modeling ◽  
Surface Excess ◽  
Ion Distributions ◽  
Charged Droplets ◽  
Hydronium Ions ◽  
Droplet Sizes ◽  
First Time

<div>Charged droplets have become a new environment for accelerating chemical reactions by orders of magnitude relative to their bulk analogues. Nevertheless the reaction mechanisms still remain unknown. Here we investigate the ion spatial distributions and surface charge in aqueous droplets with diameters in the range of 5 nm to 16 nm with and without counterions using molecular dynamics. The charge carriers are Na, Cl, I, ions and model hydronium ions. We demonstrate the convergence of ion spatial distributions. Scaling of the ion distributions reveals underlying universal behavior. The convergence allows one to extrapolate the simulation results from nanoscopic dimensions to larger ones, which are still inaccessible to atomistic modeling.</div><div>The surface excess charge and electric field are also computed. We find that the surface excess charge layer is approximately 1.5 nm-1.7 nm thick and that approximately 55%-33 % (from smaller to larger droplets) of the total number of ions reside in this layer. For the first time droplet sizes that are accessible to experimental scrutiny are modeled atomistically. </div>

Thermodynamic predicting and atomistic modeling the favored compositions for Mg–Ni–Y metallic glasses

RSC Advances ◽  
2015 ◽  
Vol 5 (74) ◽  
pp. 60220-60229 ◽  
Author(s):  
Q. Wang ◽  
J. H. Li ◽  
B. X. Liu
Keyword(s):  
Metallic Glasses ◽  
Glass Formation ◽  
Thermodynamic Calculations ◽  
Atomistic Simulations ◽  
Atomistic Modeling ◽  
Composition Design ◽  
System Glass Formation

For Mg–Ni–Y system, glass formation is jointly studied by thermodynamic calculations and atomistic simulations. The prediction results have extensive implications for the Mg-based family and could be of great help for guiding the composition design.

scholarly journals Atomistic Modeling of Gas Adsorption in Nanocarbons

2012 ◽  
Vol 2012 ◽  
pp. 1-32 ◽  
Author(s):  
G. Zollo ◽  
F. Gala
Keyword(s):  
Gas Sensors ◽  
Significant Variation ◽  
Carbon Nanostructures ◽  
Scientific Literature ◽  
Gas Adsorption ◽  
Hydrogen Adsorption ◽  
Atomistic Simulations ◽  
Atomistic Modeling ◽  
Theoretical Frameworks ◽  
Different Characteristics

Carbon nanostructures are currently under investigation as possible ideal media for gas storage and mesoporous materials for gas sensors. The recent scientific literature concerning gas adsorption in nanocarbons, however, is affected by a significant variation in the experimental data, mainly due to the different characteristics of the investigated samples arising from the variety of the synthesis techniques used and their reproducibility. Atomistic simulations have turned out to be sometimes crucial to study the properties of these systems in order to support the experiments, to indicate the physical limits inherent in the investigated structures, and to suggest possible new routes for application purposes. In consideration of the extent of the theme, we have chosen to treat in this paper the results obtained within some of the most popular atomistic theoretical frameworks without any purpose of completeness. A significant part of this paper is dedicated to the hydrogen adsorption on C-based nanostructures for its obvious importance and the exceptional efforts devoted to it by the scientific community.

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