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Effects Of Surface Charge On The Anomalous Light Extinction From Metallic Nanoparticles, Andres H. La Rosa, Edin Sijercic 2016 Portland State University

Effects Of Surface Charge On The Anomalous Light Extinction From Metallic Nanoparticles, Andres H. La Rosa, Edin Sijercic

Andres H. La Rosa

The effects of extraneous surface charges on the anomalous extinction from metallic nanoparticles are studied via an application of the extended Mie theory by Bohren and Hunt. Due to the sensitivity of the higher multipolar resonance on the surface charges, it is found that quenching of the anomalous resonance can be observed with presence of only a modest amount of charges on these particles. The observed effects thus provide a rather sensitive mechanism for the monitoring of the neutrality of these nanoparticles using far field scattering approaches.


Classical Transport In Disordered Systems, Antonios Papaioannou 2016 Graduate Center, City University of New York

Classical Transport In Disordered Systems, Antonios Papaioannou

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

This thesis reports on the manifestation of structural disorder on molecular transport and it consists of two parts. Part I discusses the relations between classical transport and the underlying structural complexity of the system. Both types of molecular diffusion, namely Gaussian and non-Gaussian are presented and the relevant time regimes are discussed. In addition the concept of structural universality is introduced and connected with the diffusion metrics. One of the most robust techniques for measuring molecular mean square displacements is magnetic resonance. This method requires encoding and subsequently reading out after an experimentally controlled time, a phase ϕ to the ...


Theoretical Analysis Of Single Molecule Spectroscopy Lineshapes Of Conjugated Polymers, Murali Devi 2016 Graduate Center, City University of New York

Theoretical Analysis Of Single Molecule Spectroscopy Lineshapes Of Conjugated Polymers, Murali Devi

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

Conjugated Polymers(CPs) exhibit a wide range of highly tunable optical properties. Quantitative and detailed understanding of the nature of excitons responsible for such a rich optical behavior has significant implications for better utilization of CPs for more efficient plastic solar cells and other novel optoelectronic devices. In general, samples of CPs are plagued with substantial inhomogeneous broadening due to various sources of disorder. Single molecule emission spectroscopy (SMES) offers a unique opportunity to investigate the energetics and dynamics of excitons and their interactions with phonon modes. The major subject of the present thesis is to analyze and understand room ...


Suppression Of High Transverse Momentum Charged Hadrons In Au+Au Collisions At 200 Gev Nucleon-Nucleon Center Of Mass Energy, Jason B. Bryslawskyj 2016 Graduate Center, City University of New York

Suppression Of High Transverse Momentum Charged Hadrons In Au+Au Collisions At 200 Gev Nucleon-Nucleon Center Of Mass Energy, Jason B. Bryslawskyj

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

The dynamical properties of quark gluon plasma are studied in heavy ion collisions. Gold ions are accelerated with the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory and collided at energies up to 200 GeV per nucleon. Collision products and their properties are detected and measured with the PHENIX detector. At these energies the colliding ions may form a thermalized distribution of quarks and gluons called the Quark-Gluon Plasma. The suppression of single hadrons still provides one of the strongest constraints on energy loss mechanisms in the Quark-Gluon Plasma. Presently, neutral pions provide the best measurement at RHIC of ...


Elements Of The Mathematical Formulation Of Quantum Mechanics, Keunjae Go 2016 Washington University in Saint Louis

Elements Of The Mathematical Formulation Of Quantum Mechanics, Keunjae Go

Senior Honors Papers / Undergraduate Theses

In this paper, we will explore some of the basic elements of the mathematical formulation of quantum mechanics. In the first section, I will list the motivations for introducing a probability model that is quite different from that of the classical probability theory, but still shares quite a few significant commonalities. Later in the paper, I will discuss the quantum probability theory in detail, while paying a brief attention to some of the axioms (by Birkhoff and von Neumann) that illustrate both the commonalities and differences between classical mechanics and quantum mechanics. This paper will end with a presentation of ...


On The Probability Summation Model For Laser-Damage Thresholds, Clifton D. Clark, Gavin D. Buffington 2016 Fort Hays State University

On The Probability Summation Model For Laser-Damage Thresholds, Clifton D. Clark, Gavin D. Buffington

Clifton D. Clark

This paper explores the probability summation model in an attempt to provide insight to the model’s utility and ultimately its validity. The model is a statistical description of multiple-pulse (MP) damage trends. It computes the probability of n pulses causing damage from knowledge of the single-pulse dose–response curve. Recently, the model has been used to make a connection between the observed n−1∕4 trends in MP damage thresholds for short pulses (<10 μs) and experimental uncertainties, suggesting that the observed trend is an artifact of experimental methods. We will consider the correct application of the model in this case. We also apply this model to the spot-size dependence of short pulse damage thresholds, which has not been done previously. Our results predict that the damage threshold trends with respect to the irradiated area should be similar to the MP damage threshold trends, and that observed spot-size dependence for short pulses seems to display this trend, which cannot be accounted for by the thermal models. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.JBO.21.1.015006]


Build Strong Bodies And Minds Through Service Learning, David Sederberg 2016 Purdue University

Build Strong Bodies And Minds Through Service Learning, David Sederberg

Purdue P-12 Networking Summit & Poster Session

In Physics and Astronomy at Purdue, service learning is an essential component to our outreach programs. While providing authentic deliverables to the “customer,” service learning engages individuals in ways through which they are able to make meaningful contributions, while at the same time developing their own knowledge and expertise in an area of personal interest or commitment. That learning may involve leadership, instructional design, communication of science fundamentals and applications to K-12 and general audiences, research, reflective practice, and the acquisition of skills that last a lifetime. This presentation illustrates ways in which we leverage resources between service learning and ...


High-Resolution Model For Noncontact Atomic Force Microscopy With A Flexible Molecule On The Tip Apex, Chun-Sheng Guo, Michel Andre Van Hove, Xinguo Ren, Yong Zhao 2016 Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R&D Center, Southwest Jiaotong University, Mail Stop 165#, Chengdu 610031, Sichuan, China

High-Resolution Model For Noncontact Atomic Force Microscopy With A Flexible Molecule On The Tip Apex, Chun-Sheng Guo, Michel Andre Van Hove, Xinguo Ren, Yong Zhao

Professor Michel Andre Van Hove

Experiments using noncontact atomic force microscopy (NC-AFM) with CO-molecule-functionalized tips have distinctly imaged chemical structures within conjugated molecules. Here we describe a detailed model based on an ab initio approach of the interaction force between the AFM tip and the sample molecule that yields atomicscale images, which agree very well with the experimental images we considered. The key ingredient of our model is to explicitly include the effect on the image due to the tilt of the CO molecule at the tip apex resulting from the lateral force exerted by the sample. On the basis of this model, we specifically ...


Symmetry-Dependent Band Gap Opening In Graphene Induced By G-C3n4 Substrates, Ji-Chang Ren, Rui-Qin Zhang, Zejun Ding, Michel Andre Van Hove 2016 USTC-CityU Joint Advanced Research Centre, Suzhou, China

Symmetry-Dependent Band Gap Opening In Graphene Induced By G-C3n4 Substrates, Ji-Chang Ren, Rui-Qin Zhang, Zejun Ding, Michel Andre Van Hove

Professor Michel Andre Van Hove

Opening the band gap in graphene can significantly broaden its applications in electronic devices. By introducing four types of graphene-like carbon nitride (g-C3N4) as the substrate of graphene, we reveal, with first principles calculations, a symmetry and size dependent band gap opening in graphene. On the one hand, for a substrate with a 3-fold rotational symmetry, a small C3N4 unit can cause a large value of the band gap in the graphene layer. On the other hand, the band gap also depends on the symmetry of the substrate. A 3-fold symmetry induces a relatively small band gap, while rectangular and ...


Stabilizing Reconstruction Induced By O Protrusions Of The Zno (0001) Polar Surface, Yu Li, Bolong Huang, Rui-Qin Zhang, Zijing Lin, Michel Andre Van Hove 2016 USTC-CityU Joint Advanced Research Centre, Suzhou, 215123, China

Stabilizing Reconstruction Induced By O Protrusions Of The Zno (0001) Polar Surface, Yu Li, Bolong Huang, Rui-Qin Zhang, Zijing Lin, Michel Andre Van Hove

Professor Michel Andre Van Hove

The stability of the ZnO polar surfaces which is crucial for their applications is still being debated intensely. Here, we demonstrate that O extrusion outside the outermost bilayer is a universal reconstruction behavior of the Zn-terminated (0001) surface (with or without terraces) to compensate the well-known instability of such polar surfaces. The study is based on first-principles energetics of several atomic reconstruction configurations that emerge spontaneously in ab initio molecular dynamics simulations, including on-site O extrusions, O interstitials and O extrusions as adatoms at hollow sites, compared with previously proposed O-rich compensation models with O adatoms and Zn vacancies. The ...


Interactions Between Organics And Metal Surfaces In The Intermediate Regime Between Physisorption And Chemisorption, Xing-Qiang Shi, Yu Li, Michel Andre Van Hove, Rui-Qin Zhang 2016 Hong Kong Baptist University

Interactions Between Organics And Metal Surfaces In The Intermediate Regime Between Physisorption And Chemisorption, Xing-Qiang Shi, Yu Li, Michel Andre Van Hove, Rui-Qin Zhang

Professor Michel Andre Van Hove

The adsorption of pentacene, perfluoropentacene, other acenes, and biphenyl on a Cu(111) single-crystal surface was studied by a modified version of a van der Waals density functional. Accurate and consistent interface geometries and adsorption energies were obtained for the first time. All studied interactions between the organics and the metal are in the sensitive intermediate regime between chemisorption and physisorption, in which regime both geometric and electronic structures of the adsorbates are strongly modified by the metal surface. Adsorption induced gentle curving of flat acenes is demonstrated and explained (the ends of the acenes curving away from the metal ...


Selective Adsorption Of L-Serine Functional Groups On The Anatase Tio2(101) Surface In Benthic Microbial Fuel Cells, Yan-Ling Zhao, Cui-Hong Wang, Ying Zhai, Rui-Qin Zhang, Michel Andre Van Hove 2016 Hong Kong Baptist University

Selective Adsorption Of L-Serine Functional Groups On The Anatase Tio2(101) Surface In Benthic Microbial Fuel Cells, Yan-Ling Zhao, Cui-Hong Wang, Ying Zhai, Rui-Qin Zhang, Michel Andre Van Hove

Professor Michel Andre Van Hove

To help design bacteria-friendly anodes for unmediated benthic microbial fuel cells (MFCs), we explore the role of anatase TiO2(101) surface biocompatibility in selecting the functional groups of the levo-isomer serine (L-Ser), which contains carboxyl, hydroxyl, and amino groups in a single molecule. By performing total energy calculations and molecular dynamics simulations based on a density-functional tight-binding method, we find that at room temperature, the surface should be active for biomolecules with carboxyl/carboxylic and hydroxyl groups, but it is not sensitive to those with amino groups. The hydrogen bonding between the hydroxyl H and surface O facilitates electron transfer ...


Strong Slip-Induced Anomalous Enhancement And Red-Shifts In Wide-Range Optical Absorption Of Graphite Under Uniaxial Pressure, Ji-Chang Ren, Rui-Qin Zhang, Zejun Ding, Michel Andre Van Hove 2016 Hong Kong Baptist University

Strong Slip-Induced Anomalous Enhancement And Red-Shifts In Wide-Range Optical Absorption Of Graphite Under Uniaxial Pressure, Ji-Chang Ren, Rui-Qin Zhang, Zejun Ding, Michel Andre Van Hove

Professor Michel Andre Van Hove

Natural graphite shows little optical response. Based on first-principles calculations, we demonstrate, for the first time, that an in-plane pressure-induced slip between atomic layers causes a strong anomalous enhancement and large red-shifts in the infrared and far infrared optical absorption by graphite. Specifically, a slip along the armchair direction induces an absorption feature that redshifts from rv3 eV to rv0.15 eV, while its intensity increases by an order of magnitude, due to an electron density delocalization effect with slip. Our results provide a way to detect and measure the magnitude of the in- plane slip of graphite under compression ...


Stabilizing Forces Acting On Zno Polar Surfaces: Stm, Leed, And Dft, H. Xu, L. Dong, X. Q. Shi, Michel Andre Van Hove, W. K. Ho, N. Lin, H. S. Wu, S. Y. Tong 2016 Hong Kong Baptist University

Stabilizing Forces Acting On Zno Polar Surfaces: Stm, Leed, And Dft, H. Xu, L. Dong, X. Q. Shi, Michel Andre Van Hove, W. K. Ho, N. Lin, H. S. Wu, S. Y. Tong

Professor Michel Andre Van Hove

New understanding has been reached on competing forces acting to stabilize the polar surfaces of intrinsic ZnO. To compensate an accumulating dipole moment normal to ionic planes, the Madelung electrostatic force and the bonding ability of undercoordinated Zn ions compete to deplete more Zn atoms from the (0001) face and more O atoms from the (0001¯) face. In this competition, the former mechanism wins because it provides very low energy binding sites for O ions at face-centered-cubic registries on both surfaces. On the Zn-face, a distorted tetrahedral structure is formed, while on the O-face, a vertical Y structure is formed ...


Oxygen Vacancy Diffusion In Bare Zno Nanowires, Bei Deng, Andreia Luisa Da Rosa, Th. Frauenheim, J. P. Xiao, X. Q. Shi, R. Q. Zhang, Michel Andre Van Hove 2016 Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, China

Oxygen Vacancy Diffusion In Bare Zno Nanowires, Bei Deng, Andreia Luisa Da Rosa, Th. Frauenheim, J. P. Xiao, X. Q. Shi, R. Q. Zhang, Michel Andre Van Hove

Professor Michel Andre Van Hove

Oxygen vacancies (VO) are known to be common native defects in zinc oxide (ZnO) and to play important roles in many applications. Based on density functional theory, we present a study for the migration of oxygen vacancies in ultra-thin ZnO nanowires (NWs). We find that under equilibrium growth conditions VO has a higher formation energy (Ef) inside the wire than that at shallow sites and surface sites, with different geometric relaxations and structural reconstructions. The migration of VO has lower barriers in the NW than in the bulk and is found to be energetically favorable in the direction from the ...


Totally Positive Density Matrices And Linear Preservers, David Kribs, Jeremy Levick, Rajesh Pereira 2016 University of Guelph

Totally Positive Density Matrices And Linear Preservers, David Kribs, Jeremy Levick, Rajesh Pereira

Electronic Journal of Linear Algebra

The intersection between the set of totally nonnegative matrices, which are of interest in many areas of matrix theory and its applications, and the set of density matrices, which provide the mathematical description of quantum states, are investigated. The single qubit case is characterized, and several equivalent conditions for a quantum channel to preserve the set in that case are given. Higher dimensional cases are also discussed.


Failure Of Surface Color Cues Under Natural Changes In Lighting, David H. Foster, Iván Marín-Franch 2016 University of Manchester

Failure Of Surface Color Cues Under Natural Changes In Lighting, David H. Foster, Iván Marín-Franch

MODVIS Workshop

Color allows us to effortlessly discriminate and identify surfaces and objects by their reflected light. Although the reflected spectrum changes with the illumination spectrum, cone photoreceptor signals can be transformed to give useful cues for surface color. But what happens when both the spectrum and the geometry of the illumination change, as with lighting from the sun and sky? Is it possible, as a matter of principle, to obtain reliable cues by processing cone signals alone? This question was addressed here by estimating the information provided by cone signals from time-lapse hyperspectral radiance images of five outdoor scenes under natural ...


The Millikan Oil Drop Experiment: A Simulation Suitable For Classroom Use, Benjamin Hogan, Javier E. Hasbun 2016 University of West Georgia

The Millikan Oil Drop Experiment: A Simulation Suitable For Classroom Use, Benjamin Hogan, Javier E. Hasbun

Georgia Journal of Science

Due to advancements in computing techniques it has become possible to extend the accessibility of physics experiments across the physics curriculum by means of computational simulations. The widespread availability of computers in modern classrooms provides virtual access to hands-on physics, chemistry, and biology experiments, among others. Here, specifically, we consider Robert Millikan’s famous oil drop experiment. This experiment requires equipment that can be dangerous and expensive. A more practical approach is achieved via a computer simulation, a useful and a universally available alternative. The goal is to encourage scientific thinking, literacy, and innovation while promoting a free network of ...


The Equivalence Problem: Einstein­Maxwell Solutions, Rebecca Whitney 2016 Utah State University

The Equivalence Problem: Einstein­Maxwell Solutions, Rebecca Whitney

Physics Capstone Project

The “Equivalence Problem” is part of the Digital Einstein Project. The goal of this project is to create a digital and interactive library of all known solutions to the Einstein field equations in general relativity. The “Equivalence Problem” involves determining when two solutions are physically equivalent. This requires calculating physical and geometric features to characterize each solution independently of any coordinate system. One of the principal features used to characterize the solutions is the degree of symmetry or the isometry group of the space­-time metric. We have focused on the solutions to the Einstein­-Maxwell field equations and compared ...


Algorithms For The Optical Profiling Of The Atmospheric Limb Radiometry Data Analysis For The Opal Cubesat, Eric D. Ashby 2016 Utah State University

Algorithms For The Optical Profiling Of The Atmospheric Limb Radiometry Data Analysis For The Opal Cubesat, Eric D. Ashby

Physics Capstone Project

The Optical Profiling of the Atmospheric Limb (OPAL) mission is a CubeSat (NSF) project with aims to measure the temperature in the thermosphere between 90 and 140 km. The temperatures are inferred from the characteristic emission lines of molecular oxygen called the O2 A-band (around 760 nm). These temperatures will be used to better understand the evolution of the upper atmosphere during a solar storm and to analyze the temperature signatures of gravity waves. Multiple steps are required to retrieve temperature data from the OPAL satellite. Initially, the data must be deconvoluted from line-of-sight images. Spectral data must then be ...


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