The present work addressed in this thesis introduces, for the first time, the use of tilted fiber Bragg grating (TFBG) sensors for accurate, real-time, and in-situ characterization of CVD and ALD processes for noble metals, but with a particular focus on gold due to its desirable optical and plasmonic properties. Through the use of orthogonally-polarized transverse electric (TE) and transverse magnetic (TM) resonance modes imposed by a boundary condition at the cladding-metal interface of the optical fiber, polarization-dependent resonances excited by the TFBG are easily decoupled. It was found that for ultrathin thicknesses of gold films from CVD (~6-65 nm), the anisotropic property of these films made it non-trivial to characterize their effective optical properties such as the real component of the permittivity. Nevertheless, the TFBG introduces a new sensing platform to the ALD and CVD community for extremely sensitive in-situ process monitoring. We later also demonstrate thin film growth at low (<10 cycle) numbers for the well-known Al2O3 thermal ALD process, as well as the plasma-enhanced gold ALD process. Finally, the use of ALD-grown gold coatings has been employed for the development of a plasmonic TFBG-based sensor with ultimate refractometric sensitivity (~550 nm/RIU).
{"title":"In-situ Optical Characterization of Noble Metal Thin Film Deposition and Development of a High-performance Plasmonic Sensor","authors":"David J. Mandia","doi":"10.22215/etd/2016-11620","DOIUrl":"https://doi.org/10.22215/etd/2016-11620","url":null,"abstract":"The present work addressed in this thesis introduces, for the first time, the use of tilted fiber Bragg grating (TFBG) sensors for accurate, real-time, and in-situ characterization of CVD and ALD processes for noble metals, but with a particular focus on gold due to its desirable optical and plasmonic properties. Through the use of orthogonally-polarized transverse electric (TE) and transverse magnetic (TM) resonance modes imposed by a boundary condition at the cladding-metal interface of the optical fiber, polarization-dependent resonances excited by the TFBG are easily decoupled. It was found that for ultrathin thicknesses of gold films from CVD (~6-65 nm), the anisotropic property of these films made it non-trivial to characterize their effective optical properties such as the real component of the permittivity. Nevertheless, the TFBG introduces a new sensing platform to the ALD and CVD community for extremely sensitive in-situ process monitoring. We later also demonstrate thin film growth at low (<10 cycle) numbers for the well-known Al2O3 thermal ALD process, as well as the plasma-enhanced gold ALD process. Finally, the use of ALD-grown gold coatings has been employed for the development of a plasmonic TFBG-based sensor with ultimate refractometric sensitivity (~550 nm/RIU).","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72759308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ruiqi Zhao, Hongzhang Wang, Jianbo Tang, W. Rao, Jing Liu
We report a gas eruption phenomenon caused by electrolysis of liquid Ga-In alloy in an electrolyte, especially NaOH solution. A volcanic eruption-like blowout of gas occurred from the orifice on the alloy surface. In addition to gas plume, large gas bubbles were also generated and the total gas yield increased as In ratio was increased. It is found that destructiveness of the passivation layer on the Ga-In alloy is critical to gas generation. The mechanism of gas eruption can be ascribed to a galvanic interaction happens owing to passivation film and alloy with different activity connected as electrode in electrolyte. Further investigation demonstrated that the lattice of the film expands because of the incorporation of indium, which brings about the decrease in band gap and finally enhances more gas generation. These findings regain the basic understanding of room temperature liquid metal inside electrolyte.
{"title":"Gas Eruption Phenomenon Happening from Ga-In Alloy in Electrolyte","authors":"Ruiqi Zhao, Hongzhang Wang, Jianbo Tang, W. Rao, Jing Liu","doi":"10.1063/1.5017949","DOIUrl":"https://doi.org/10.1063/1.5017949","url":null,"abstract":"We report a gas eruption phenomenon caused by electrolysis of liquid Ga-In alloy in an electrolyte, especially NaOH solution. A volcanic eruption-like blowout of gas occurred from the orifice on the alloy surface. In addition to gas plume, large gas bubbles were also generated and the total gas yield increased as In ratio was increased. It is found that destructiveness of the passivation layer on the Ga-In alloy is critical to gas generation. The mechanism of gas eruption can be ascribed to a galvanic interaction happens owing to passivation film and alloy with different activity connected as electrode in electrolyte. Further investigation demonstrated that the lattice of the film expands because of the incorporation of indium, which brings about the decrease in band gap and finally enhances more gas generation. These findings regain the basic understanding of room temperature liquid metal inside electrolyte.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80534187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Zenkri, D. D. Caprio, C. P'erez-Brokate, D. F'eron, J. D. Lamare, A. Chauss'e, F. Larbi, F. Raouafi
We present a stochastic CA modelling approach of corrosion based on spatially separated electrochemical half-reactions, diffusion, acido-basic neutralization in solution and passive properties of the oxide layers. Starting from different initial conditions, a single framework allows one to describe generalised corrosion, localised corrosion, reactive and passive surfaces, including occluded corrosion phenomena as well. Spontaneous spatial separation of anodic and cathodic zones is associated with bare metal and passivated metal on the surface. This separation is also related to local acidification of the solution. This spontaneous change is associated with a much faster corrosion rate. Material morphology is closely related to corrosion kinetics, which can be used for technological applications.
{"title":"Contribution of cellular automata to the understanding of corrosion phenomena","authors":"M. Zenkri, D. D. Caprio, C. P'erez-Brokate, D. F'eron, J. D. Lamare, A. Chauss'e, F. Larbi, F. Raouafi","doi":"10.5488/CMP.20.33802","DOIUrl":"https://doi.org/10.5488/CMP.20.33802","url":null,"abstract":"We present a stochastic CA modelling approach of corrosion based on spatially separated electrochemical half-reactions, diffusion, acido-basic neutralization in solution and passive properties of the oxide layers. Starting from different initial conditions, a single framework allows one to describe generalised corrosion, localised corrosion, reactive and passive surfaces, including occluded corrosion phenomena as well. Spontaneous spatial separation of anodic and cathodic zones is associated with bare metal and passivated metal on the surface. This separation is also related to local acidification of the solution. This spontaneous change is associated with a much faster corrosion rate. Material morphology is closely related to corrosion kinetics, which can be used for technological applications.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78567846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-08-31DOI: 10.26434/chemrxiv.5371498
S. Kristyán
The Brillouin theorem has been generalized for the extended non-relativistic electronic Hamiltonian (Hkin+ Hne+ aHee) in relation to coupling strength parameter (a), as well as for the configuration interactions (CI) formalism in this respect. For a computation support, we have made a particular modification of the SCF part in the Gaussian package: essentially a single line was changed in an SCF algorithm, wherein the operator rij-1 was overwritten as 1/rij to a/rij, and a was used as input. The case a=0 generates an orto-normalized set of Slater determinants which can be used as a basis set for CI calculations for the interesting physical case a=1, removing the known restriction by Brillouin theorem with this trick. The latter opens a door from the theoretically interesting subject of this work toward practice.
{"title":"Generalization of Brillouin theorem for the non-relativistic electronic Schrödinger equation in relation to coupling strength parameter, and its consequences in single determinant basis sets for configuration interactions","authors":"S. Kristyán","doi":"10.26434/chemrxiv.5371498","DOIUrl":"https://doi.org/10.26434/chemrxiv.5371498","url":null,"abstract":"The Brillouin theorem has been generalized for the extended non-relativistic electronic Hamiltonian (Hkin+ Hne+ aHee) in relation to coupling strength parameter (a), as well as for the configuration interactions (CI) formalism in this respect. For a computation support, we have made a particular modification of the SCF part in the Gaussian package: essentially a single line was changed in an SCF algorithm, wherein the operator rij-1 was overwritten as 1/rij to a/rij, and a was used as input. The case a=0 generates an orto-normalized set of Slater determinants which can be used as a basis set for CI calculations for the interesting physical case a=1, removing the known restriction by Brillouin theorem with this trick. The latter opens a door from the theoretically interesting subject of this work toward practice.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81058651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-05DOI: 10.2961/jlmn.2017.03.0014
E. Barmina, S. Gudkov, A. Simakin, G. A. Shafeev
The formation of stable products of water decomposition under laser exposure of aqueous colloidal solutions of nanoparticles is experimentally studied. Laser exposure of colloidal solutions leads to formation of H2, O2, and H2O2. The dependence of the yield of these products depends on the energy density of laser radiation inside the liquid and concentration of nanoparticles. The ratio H2/O2 depends on laser fluence and is shifted towards H2. There are at least to sources of H2O2, namely, laser-induced breakdown plasma and ultrasound induced by laser pulses in the liquid. The formation of both H2 and O2 is tentatively assigned to direct dissociation of H2O molecules by electron impact from laser-induced plasma.
{"title":"Stable products of laser-induced breakdown of aqueous colloidal solutions of nanoparticles","authors":"E. Barmina, S. Gudkov, A. Simakin, G. A. Shafeev","doi":"10.2961/jlmn.2017.03.0014","DOIUrl":"https://doi.org/10.2961/jlmn.2017.03.0014","url":null,"abstract":"The formation of stable products of water decomposition under laser exposure of aqueous colloidal solutions of nanoparticles is experimentally studied. Laser exposure of colloidal solutions leads to formation of H2, O2, and H2O2. The dependence of the yield of these products depends on the energy density of laser radiation inside the liquid and concentration of nanoparticles. The ratio H2/O2 depends on laser fluence and is shifted towards H2. There are at least to sources of H2O2, namely, laser-induced breakdown plasma and ultrasound induced by laser pulses in the liquid. The formation of both H2 and O2 is tentatively assigned to direct dissociation of H2O molecules by electron impact from laser-induced plasma.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79941475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The delocalization error of popular density functional approximations (DFAs) leads to diversified problems in present-day density functional theory calculations. For achieving a universal elimination of delocalization error, we develop a localized orbital scaling correction (LOSC) framework, which unifies our previously proposed global and local scaling approaches. The LOSC framework accurately characterizes the distributions of global and local fractional electrons, and is thus capable of correcting system energy, energy derivative and electron density in a self-consistent and size-consistent manner. The LOSC-DFAs lead to systematically improved results, including the dissociation of cationic species, the band gaps of molecules and polymer chains, the energy and density changes upon electron addition and removal, and photoemission spectra.
{"title":"Localized Orbital Scaling Correction for Systematic Elimination of Delocalization Error in Density Functional Approximations","authors":"Chen Li, Xiao Zheng, N. Su, Weitao Yang","doi":"10.1093/nsr/nwx111","DOIUrl":"https://doi.org/10.1093/nsr/nwx111","url":null,"abstract":"The delocalization error of popular density functional approximations (DFAs) leads to diversified problems in present-day density functional theory calculations. For achieving a universal elimination of delocalization error, we develop a localized orbital scaling correction (LOSC) framework, which unifies our previously proposed global and local scaling approaches. The LOSC framework accurately characterizes the distributions of global and local fractional electrons, and is thus capable of correcting system energy, energy derivative and electron density in a self-consistent and size-consistent manner. The LOSC-DFAs lead to systematically improved results, including the dissociation of cationic species, the band gaps of molecules and polymer chains, the energy and density changes upon electron addition and removal, and photoemission spectra.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79215539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-08DOI: 10.1007/978-3-319-29022-5_4
Shant Shahbazian
{"title":"Extending the Topological Analysis and Seeking the Real-Space Subsystems in Non-Coulombic Systems with Homogeneous Potential Energy Functions","authors":"Shant Shahbazian","doi":"10.1007/978-3-319-29022-5_4","DOIUrl":"https://doi.org/10.1007/978-3-319-29022-5_4","url":null,"abstract":"","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"85 3 1","pages":"89-100"},"PeriodicalIF":0.0,"publicationDate":"2017-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77295996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-05-17DOI: 10.1021/jacs.6b08842.s001
Understanding the oxidation and reduction mechanisms of catalytically active transition metal nanoparticles is important to improve their application in a variety of chemical processes. In nanocatalysis the nanoparticles can undergo oxidation or reduction in situ, and thus the redox species are not what are observed before and after reactions. We have used the novel environmental scanning transmission electron microscope (ESTEM) with 0.1 nm resolution in systematic studies of complex dynamic oxidation and reduction mechanisms of copper nanoparticles. The oxidation of copper has previously been reported to be dependent on its crystallography and its interaction with the substrate. By following the dynamic oxidation process in situ, in real time, with high-angle annular dark-field imaging in the ESTEM, we use conditions ideal to track the oxidation front as it progresses across a copper nanoparticle by following the changes in the atomic number (z) contrast with time. The oxidation occurs via the nucleation of the oxide phase (Cu2O) from one area of the nanoparticle which then progresses unidirectionally across the particle, with the Cu-to-Cu2O interface having a relationship of Cu{111} parallel to Cu2O{111}. The oxidation kinetics are related to the temperature and oxygen pressure. When the process is reversed in hydrogen, the reduction process is observed to be similar to the oxidation, with the same crystallographic relationship between the two phases. The dynamic observations provide unique insights into redox mechanisms which are important to understanding and controlling the oxidation and reduction of copper-based nanoparticles.
{"title":"Visualizing the Cu and Cu2O Interface Transition in Nanoparticles with Environmental Scanning Transmission Electron Microscopy","authors":"","doi":"10.1021/jacs.6b08842.s001","DOIUrl":"https://doi.org/10.1021/jacs.6b08842.s001","url":null,"abstract":"Understanding the oxidation and reduction mechanisms of catalytically active transition metal nanoparticles is important to improve their application in a variety of chemical processes. In nanocatalysis the nanoparticles can undergo oxidation or reduction in situ, and thus the redox species are not what are observed before and after reactions. We have used the novel environmental scanning transmission electron microscope (ESTEM) with 0.1 nm resolution in systematic studies of complex dynamic oxidation and reduction mechanisms of copper nanoparticles. The oxidation of copper has previously been reported to be dependent on its crystallography and its interaction with the substrate. By following the dynamic oxidation process in situ, in real time, with high-angle annular dark-field imaging in the ESTEM, we use conditions ideal to track the oxidation front as it progresses across a copper nanoparticle by following the changes in the atomic number (z) contrast with time. The oxidation occurs via the nucleation of the oxide phase (Cu2O) from one area of the nanoparticle which then progresses unidirectionally across the particle, with the Cu-to-Cu2O interface having a relationship of Cu{111} parallel to Cu2O{111}. The oxidation kinetics are related to the temperature and oxygen pressure. When the process is reversed in hydrogen, the reduction process is observed to be similar to the oxidation, with the same crystallographic relationship between the two phases. The dynamic observations provide unique insights into redox mechanisms which are important to understanding and controlling the oxidation and reduction of copper-based nanoparticles.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84421561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitai Sylvetsky, Manoj K. Kesharwani, Jan M. L. Martin
Complementary auxiliary basis sets for F12 explicitly correlated calculations appear to be more transferable between orbital basis sets than has been generally assumed. We also find that aVnZ-F12 basis sets, originally developed with anionic systems in mind, appear to be superior for noncovalent interactions as well, and propose a suitable CABS sequence for them.
{"title":"MP2-F12 Basis Set Convergence for the S66 Noncovalent Interactions Benchmark: Transferability of the Complementary Auxiliary Basis Set (CABS)","authors":"Nitai Sylvetsky, Manoj K. Kesharwani, Jan M. L. Martin","doi":"10.1063/1.5012285","DOIUrl":"https://doi.org/10.1063/1.5012285","url":null,"abstract":"Complementary auxiliary basis sets for F12 explicitly correlated calculations appear to be more transferable between orbital basis sets than has been generally assumed. We also find that aVnZ-F12 basis sets, originally developed with anionic systems in mind, appear to be superior for noncovalent interactions as well, and propose a suitable CABS sequence for them.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76480427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The thesis focuses on the prediction of solvation thermodynamics using integral equation theories. Our main goal is to improve the approach using a rational correction. We achieve it by extending recently introduced pressure correction, and rationalizing it in the context of solvation entropy. The improved model (to which we refer as advanced pressure correction) is rather universal. It can accurately predict solvation free energies in water at both ambient and non-ambient temperatures, is capable of addressing ionic solutes and salt solutions, and can be extended to non-aqueous systems. The developed approach can be used to model processes in biological systems, as well as to extend related theoretical models further.
{"title":"Can approximate integral equation theories accurately predict solvation thermodynamics","authors":"M. Misin","doi":"10.5281/zenodo.495336","DOIUrl":"https://doi.org/10.5281/zenodo.495336","url":null,"abstract":"The thesis focuses on the prediction of solvation thermodynamics using integral equation theories. Our main goal is to improve the approach using a rational correction. We achieve it by extending recently introduced pressure correction, and rationalizing it in the context of solvation entropy. The improved model (to which we refer as advanced pressure correction) is rather universal. It can accurately predict solvation free energies in water at both ambient and non-ambient temperatures, is capable of addressing ionic solutes and salt solutions, and can be extended to non-aqueous systems. The developed approach can be used to model processes in biological systems, as well as to extend related theoretical models further.","PeriodicalId":8439,"journal":{"name":"arXiv: Chemical Physics","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72890480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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