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Missouri University of Science and Technology

2015

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Articles 1 - 30 of 175

Full-Text Articles in Physical Sciences and Mathematics

Evaluating Different Distributed-Cyber-Infrastructure For Data And Compute Intensive Scientific Application, Arghya Kusum Das, Seung Jong Park, Jaeki Hong, Wooseok Chang Dec 2015

Evaluating Different Distributed-Cyber-Infrastructure For Data And Compute Intensive Scientific Application, Arghya Kusum Das, Seung Jong Park, Jaeki Hong, Wooseok Chang

Computer Science Faculty Research & Creative Works

Scientists are increasingly using the current state of the art big data analytic software (e.g., Hadoop, Giraph, etc.) for their data-intensive applications over HPC environment. However, understanding and designing the hardware environment that these data- and compute-intensive applications require for good performance is challenging. With this motivation, we evaluated the performance of big data software over three different distributed-cyber-infrastructures, including a traditional HPC-cluster called SuperMikeII, a regular datacenter called SwatIII, and a novel MicroBrick-based hyperscale system called CeresII, using our own benchmark Parallel Genome Assembler (PGA). PGA is developed atop Hadoop and Giraph and serves as a good real-world example …


Method And Apparatus For Cancer Screening, Yinfa Ma, Stephen Gibbons Dec 2015

Method And Apparatus For Cancer Screening, Yinfa Ma, Stephen Gibbons

Chemistry Faculty Research & Creative Works

A method and apparatus for detection of pteridine levels in a biological sample using CE-LIF which is useful for early cancer screening involving fully oxidizing pteridine compounds in a sample such as a urine sample, subjecting to CE-LIF to assess compound concentration, and compare to expected levels in for healthy or cancer-bearing patients.


Discrete Grüss Type Inequality On Fractional Calculus, Elvan Akin, Serkan Asliyuce, Ayse Feza Guvenilir, Billur Kaymakcalan Dec 2015

Discrete Grüss Type Inequality On Fractional Calculus, Elvan Akin, Serkan Asliyuce, Ayse Feza Guvenilir, Billur Kaymakcalan

Mathematics and Statistics Faculty Research & Creative Works

We give a discrete Grüss type inequality on fractional calculus.


Control Of Mesoscopic Transport By Modifying Transmission Channels In Opaque Media, Raktim Sarma, Alexey Yamilov, Seng Fatt Liew, Mikhael Guy, Hui Cao Dec 2015

Control Of Mesoscopic Transport By Modifying Transmission Channels In Opaque Media, Raktim Sarma, Alexey Yamilov, Seng Fatt Liew, Mikhael Guy, Hui Cao

Physics Faculty Research & Creative Works

While controlling particle diffusion in a confined geometry is a popular approach taken by both natural and artificial systems, it has not been widely adopted for controlling light transport in random media, where wave interference effects play a critical role. The transmission eigenchannels determine not only light propagation through the disordered system but also the energy concentrated inside. Here, we propose and demonstrate an effective approach to modify these channels, whose structures are considered to be universal in conventional diffusive waveguides. By adjusting the waveguide geometry, we are able to alter the spatial profiles of the transmission eigenchannels significantly and …


Modeling Of Gas Production From Shale Reservoirs Considering Multiple Transport Mechanisms, Chaohua Guo, Mingzhen Wei, Hong Liu Dec 2015

Modeling Of Gas Production From Shale Reservoirs Considering Multiple Transport Mechanisms, Chaohua Guo, Mingzhen Wei, Hong Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when …


Hierarchical Segmentation Of The Malawi Rift: The Influence Of Inherited Lithospheric Heterogeneity And Kinematics In The Evolution Of Continental Rifts, Daniel A. Lao-Davila, Haifa S. Al-Salmi, Mohamed G. Abdel Salam, Estella A. Atekwana Dec 2015

Hierarchical Segmentation Of The Malawi Rift: The Influence Of Inherited Lithospheric Heterogeneity And Kinematics In The Evolution Of Continental Rifts, Daniel A. Lao-Davila, Haifa S. Al-Salmi, Mohamed G. Abdel Salam, Estella A. Atekwana

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We used detailed analysis of Shuttle Radar Topography Mission-digital elevation model and observations from aeromagnetic data to examine the influence of inherited lithospheric heterogeneity and kinematics in the segmentation of largely amagmatic continental rifts. We focused on the Cenozoic Malawi Rift, which represents the southern extension of the Western Branch of the East African Rift System. This north trending rift traverses Precambrian and Paleozoic-Mesozoic structures of different orientations. We found that the rift can be hierarchically divided into first-order and second-order segments. In the first-order segmentation, we divided the rift into Northern, Central, and Southern sections. In its Northern Section, …


Mixed-Criticality Job Models: A Comparison, Sanjoy K. Baruah, Zhishan Guo Dec 2015

Mixed-Criticality Job Models: A Comparison, Sanjoy K. Baruah, Zhishan Guo

Computer Science Faculty Research & Creative Works

The Vestal model in widely used in the real-time scheduling community for representing mixed-criticality real-time workloads. This model requires that multiple WCET estimates -- one for each criticality level in a system -- be obtained for each task. Burns suggests that being required to obtain too many WCET estimates may place an undue burden on system developers, and proposes a simplification to the Vestal model that makes do with just two WCET estimates per task. Burns makes a convincing case in favor of adopting this simplified model; here, we report on our attempts at comparing the two models -- Vestal’s …


Biomaterial Compositions, Kathleen V. Kilway, Lynda F. Bonewald, Thomas P. Schuman Nov 2015

Biomaterial Compositions, Kathleen V. Kilway, Lynda F. Bonewald, Thomas P. Schuman

Chemistry Faculty Research & Creative Works

Biomaterial compositions comprising organosilicon monomers (such as silorane monomers) and chemical curing systems or dual chemical/light curing systems, in conjunction with optional tetraoxaspiro[5.5]undecanes (“TOSUs”) and/or fillers. The present invention is directed to biomaterial compositions, as well as methods for manufacturing the same, and methods of using the compositions. The biomaterial composition comprises one or more organosilicon monomers (such as a silorane) and a chemical curing system or dual chemicaVlight curing system for polymerizing the 10 monomer(s). The compositions may include one or more tetraoxaspiro[5.5]undecanes “TOSUs”) and/or fillers. Accelerators (such as photoacids), photosensitizers, and/or electron donors may also be included in …


Functionalized Nanodiamond Reinforced Biopolymers, Gongyao Zhou, Peter I. Lelkes, Yury Gogotsi, Vadym Mochalin Nov 2015

Functionalized Nanodiamond Reinforced Biopolymers, Gongyao Zhou, Peter I. Lelkes, Yury Gogotsi, Vadym Mochalin

Chemistry Faculty Research & Creative Works

The present invention includes a composition for implantation in a patient, comprising surface-functionalized nanodiamonds and at least one biodegradable biocompatible polymer. The present invention also includes a surgical fixation device for use in a patient.


Systems And Methods For Emergency Situation Communications, Sriram Chellappan, Srinivas Thandu, Patrick Sullivan, Levi Malott Nov 2015

Systems And Methods For Emergency Situation Communications, Sriram Chellappan, Srinivas Thandu, Patrick Sullivan, Levi Malott

Computer Science Faculty Research & Creative Works

A system for enabling communications during an emergency situation is described. A system may be configured to generate graphical user interfaces including a map displaying a location and a status of the one or more users located at the scene of an emergency situation. The graphical user interfaces may be displayed on a user's portable computing device. The graphical user interfaces may be displayed at a computing device located at a dispatcher site.


Resonant Quantum Dynamics Of Few Ultracold Bosons In Periodically Driven Finite Lattices, Simeon I. Mistakidis, T. Wulf, A. Negretti, P. Schmelcher Nov 2015

Resonant Quantum Dynamics Of Few Ultracold Bosons In Periodically Driven Finite Lattices, Simeon I. Mistakidis, T. Wulf, A. Negretti, P. Schmelcher

Physics Faculty Research & Creative Works

The Out-Of-Equilibrium Dynamics Of Finite Ultracold Bosonic Ensembles In Periodically Driven One-Dimensional Optical Lattices Is Investigated. Our Study Reveals That The Driving Enforces The Bosons In Different Wells To Oscillate In-Phase And To Exhibit A Dipole-Like Mode. A Wide Range From Weak-To-Strong Driving Frequencies Is Covered And A Resonance-Like Behavior Of The Intra-Well Dynamics Is Discussed. In The Proximity Of The Resonance A Rich Intraband Excitation Spectrum Is Observed. The Single Particle Excitation Mechanisms Are Studied In The Framework Of Floquet Theory Elucidating The Role Of The Driving Frequency. The Impact Of The Interatomic Repulsive Interactions Is Examined In Detail …


The Stripe 82 Massive Galaxy Project. I. Catalog Construction, Kevin Bundy, Alexie Leauthaud, Shun Saito, For Full List Of Authors, See Publisher's Website. Nov 2015

The Stripe 82 Massive Galaxy Project. I. Catalog Construction, Kevin Bundy, Alexie Leauthaud, Shun Saito, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The Stripe 82 Massive Galaxy Catalog (S82-MGC) is the largest-volume stellar mass-limited sample of galaxies beyond z ≈ 0.1 constructed to date. Spanning 139.4 deg2, the S82-MGC includes a mass-limited sample of 41,770 galaxies with log M*/M ≳ 11.2 to z ≈ 0.7, sampling a volume of 0.3 Gpc3, roughly equivalent to the volume of the Sloan Digital Sky Survey-I/II (SDSS-I/II) z < 0.15 main sample. The catalog is built on three pillars of survey data: the SDSS Stripe 82 Coadd photometry which reaches r-band magnitudes of ∼23.5 AB, Y JHK photometry at depths of 20th magnitude (AB) from the UK Infrared Deep Sky Survey Large Area Survey, and over 70,000 spectroscopic galaxy redshifts from the SDSS-I/II and the Baryon Oscillation Spectroscopic Survey. We describe the catalog construction and verification, the production of 9-band matched aperture photometry, tests of existing and newly estimated photometric redshifts required to supplement spectroscopic redshifts for 55% of the log M*/M ≳ 11.2 sample, and geometric masking. We provide near-IR based stellar mass estimates and compare these to previous estimates. All catalog products are made publicly available. The S82-MGC …


Real-Time Supervised Detection Of Pink Areas In Dermoscopic Images Of Melanoma: Importance Of Color Shades, Texture And Location, Ravneet Kaur, P. P. Albano, Justin G. Cole, Jason R. Hagerty, Robert W. Leander, Randy Hays Moss, William V. Stoecker Nov 2015

Real-Time Supervised Detection Of Pink Areas In Dermoscopic Images Of Melanoma: Importance Of Color Shades, Texture And Location, Ravneet Kaur, P. P. Albano, Justin G. Cole, Jason R. Hagerty, Robert W. Leander, Randy Hays Moss, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

Background/Purpose: Early detection of malignant melanoma is an important public health challenge. In the USA, dermatologists are seeing more melanomas at an early stage, before classic melanoma features have become apparent. Pink color is a feature of these early melanomas. If rapid and accurate automatic detection of pink color in these melanomas could be accomplished, there could be significant public health benefits.

Methods: Detection of three shades of pink (light pink, dark pink, and orange pink) was accomplished using color analysis techniques in five color planes (red, green, blue, hue, and saturation). Color shade analysis was performed using a logistic …


Efficient Aerial Data Collection With Uav In Large-Scale Wireless Sensor Networks, Chengliang Wang, Fei Ma, Junhui Yan, Debraj De, Sajal K. Das Nov 2015

Efficient Aerial Data Collection With Uav In Large-Scale Wireless Sensor Networks, Chengliang Wang, Fei Ma, Junhui Yan, Debraj De, Sajal K. Das

Computer Science Faculty Research & Creative Works

Data collection from deployed sensor networks can be with static sink, ground-based mobile sink, or Unmanned Aerial Vehicle (UAV) based mobile aerial data collector. Considering the large-scale sensor networks and peculiarity of the deployed environments, aerial data collection based on controllable UAV has more advantages. In this paper, we have designed a basic framework for aerial data collection, which includes the following five components: deployment of networks, nodes positioning, anchor points searching, fast path planning for UAV, and data collection from network. We have identified the key challenges in each of them and have proposed efficient solutions. This includes proposal …


Using Geometry To Manipulate Long-Range Correlation Of Light Inside Disordered Media, Raktim Sarma, Alexey Yamilov, Pauf Neupane, Hui Cao Nov 2015

Using Geometry To Manipulate Long-Range Correlation Of Light Inside Disordered Media, Raktim Sarma, Alexey Yamilov, Pauf Neupane, Hui Cao

Physics Faculty Research & Creative Works

We demonstrate an effective approach of modifying the long-range spatial correlation for light propagating inside random photonic waveguides by varying the shape of the waveguide. The functional form of spatial correlation is no longer universal in the regime of diffusive transport and becomes shape dependent due to the nonlocal nature of wave propagation. The spatial dependence of the correlation may become asymmetric for light incident from opposite ends of the waveguide. This work opens the door to control nonlocal effects in mesoscopic transport of waves by tailoring the geometry of random systems. .


Bounds On Large Extra Dimensions From The Simulation Of Black Hole Events At The Lhc, Shaoqi Hou, Benjamin Harms, Marco Cavaglia Nov 2015

Bounds On Large Extra Dimensions From The Simulation Of Black Hole Events At The Lhc, Shaoqi Hou, Benjamin Harms, Marco Cavaglia

Physics Faculty Research & Creative Works

If large extra dimensions exist, the Planck scale may be as low as a TeV and microscopic black holes may be produced in high-energy particle collisions at this energy scale. We simulate microscopic black hole formation at the Large Hadron Collider and compare the simulation results with recent experimental data by the Compact Muon Solenoid collaboration. The absence of observed black hole events in the experimental data allows us to set lower bounds on the Planck scale and various parameters related to microscopic black hole formation for a number (3 − 6) of extra dimensions. Our analysis sets lower bounds …


Infinite-Noise Criticality: Nonequilibrium Phase Transitions In Fluctuating Environments, Thomas Vojta, José A. Hoyos Nov 2015

Infinite-Noise Criticality: Nonequilibrium Phase Transitions In Fluctuating Environments, Thomas Vojta, José A. Hoyos

Physics Faculty Research & Creative Works

We study the effects of time-varying environmental noise on nonequilibrium phase transitions in spreading and growth processes. Using the examples of the logistic evolution equation as well as the contact process, we show that such temporal disorder gives rise to a distinct type of critical points at which the effective noise amplitude diverges on long time scales. This leads to enormous density fluctuations characterized by an infinitely broad probability distribution at criticality. We develop a real-time renormalization-group theory that provides a general framework for the effects of temporal disorder on nonequilibrium processes. We also discuss how general this exotic critical …


Reconstruction Of Two-Dimensional Molecular Structure With Laser-Induced Electron Diffraction From Laser-Aligned Polyatomic Molecules, Chao Yu, Hui Wei, Xu Wang, Anh-Thu Le, Ruifeng Lu, C. D. Lin Oct 2015

Reconstruction Of Two-Dimensional Molecular Structure With Laser-Induced Electron Diffraction From Laser-Aligned Polyatomic Molecules, Chao Yu, Hui Wei, Xu Wang, Anh-Thu Le, Ruifeng Lu, C. D. Lin

Physics Faculty Research & Creative Works

Imaging the transient process of molecules has been a basic way to investigate photochemical reactions and dynamics. Based on laser-induced electron diffraction and partial one-dimensional molecular alignment, here we provide two effective methods for reconstructing two-dimensional structure of polyatomic molecules. We demonstrate that electron diffraction images in both scattering angles and broadband energy can be utilized to retrieve complementary structure information, including positions of light atoms. With picometre spatial resolution and the inherent femtosecond temporal resolution of lasers, laser-induced electron diffraction method offers significant opportunities for probing atomic motion in a large molecule in a typical pump-probe measurement.


A Joint Receiver Function And Gravity Study Of Crustal Structure Beneath The Incipient Okavango Rift, Botswana, Youqiang Yu, Kelly H. Liu, Cory A. Reed, Moikwathai Moidaki, Kevin Mickus, Estella A. Atekwana, Stephen S. Gao Oct 2015

A Joint Receiver Function And Gravity Study Of Crustal Structure Beneath The Incipient Okavango Rift, Botswana, Youqiang Yu, Kelly H. Liu, Cory A. Reed, Moikwathai Moidaki, Kevin Mickus, Estella A. Atekwana, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Rifting incorporates the fundamental processes concerning the breakup of continental lithosphere and plays a significant role in the formation and evolution of sedimentary basins. In order to decipher the characteristics of rifting at its earliest stage, we conduct the first teleseismic crustal study of one of the world's youngest continental rifts, the Okavango Rift Zone (ORZ), where the magma has not yet breached the surface. Results from receiver function stacking and gravity modeling indicate that the crust/mantle boundary beneath the ORZ is uplifted by 4-5 km, and the initiation of the ORZ is closely related to lithospheric stretching. Possible decompression …


Comparison Of Experimental And Theoretical Electron-Impact-Ionization Triple-Differential Cross Sections For Ethane, Esam Ali, Kate Nixon, Andrw Murray, Chuangang Ning, James Colgan, Don H. Madison Oct 2015

Comparison Of Experimental And Theoretical Electron-Impact-Ionization Triple-Differential Cross Sections For Ethane, Esam Ali, Kate Nixon, Andrw Murray, Chuangang Ning, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

We have recently examined electron-impact ionization of molecules that have one large atom at the center, surrounded by H nuclei (H2O, NH3, CH4). All of these molecules have ten electrons; however, they vary in their molecular symmetry. We found that the triple-differential cross sections (TDCSs) for the highest occupied molecular orbitals (HOMOs) were similar, as was the character of the HOMO orbitals which had a p-type "peanut" shape. In this work, we examine ethane (C2H6) which is a molecule that has two large atoms surrounded by H nuclei, so that …


Classical Dynamics Of The Abelian Higgs Model From The Critical Point And Beyond, Garyfallia C. Katsimiga, F. K. Diakonos, X. N. Maintas Sep 2015

Classical Dynamics Of The Abelian Higgs Model From The Critical Point And Beyond, Garyfallia C. Katsimiga, F. K. Diakonos, X. N. Maintas

Physics Faculty Research & Creative Works

We present two different families of solutions of the U(1)-Higgs model in a (1. +. 1) dimensional setting leading to a localization of the gauge field. First we consider a uniform background (the usual vacuum), which corresponds to the fully higgsed-superconducting phase. Then we study the case of a non-uniform background in the form of a domain wall which could be relevantly close to the critical point of the associated spontaneous symmetry breaking. For both cases we obtain approximate analytical nodeless and nodal solutions for the gauge field resulting as bound states of an effective Pöschl-Teller potential created by the …


Low-Energy (E₀ = 65 Ev) Electron-Impact Ionization Of Neon: Internormalized Triple-Differentical Cross Sections In 3d Kinematics, Xueguang Ren, Sadek M. Amami, Oleg I. Zatsarinny, Thomas Pfluger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn Sep 2015

Low-Energy (E₀ = 65 Ev) Electron-Impact Ionization Of Neon: Internormalized Triple-Differentical Cross Sections In 3d Kinematics, Xueguang Ren, Sadek M. Amami, Oleg I. Zatsarinny, Thomas Pfluger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn

Physics Faculty Research & Creative Works

We present a combined experimental and theoretical study on the low-energy (E0 = 65 eV) electron- impact ionization of neon. The experimental data are compared to predictions from a hybrid second-order distorted-wave Born plus R-matrix approach (DWB2-RM), the distorted-wave Born approximation with inclusion of post-collision interaction (DWBA-PCI), a three-body distorted-wave approach (3DW), and a B-spline R-matrix (BSR) with pseudostates approach. Excellent agreement is found between experiment and the 3DW and BSR theories. The importance of PCI effects is clearly visible in this low-energy electron-impact ionization process.


First Evidence Of Interference Effects In The Ionization Of N₂ Molecule, Zehra Nur Ozer, Hari Chaluvadi, Mevlut Dogan, James Colgan, Don H. Madison Sep 2015

First Evidence Of Interference Effects In The Ionization Of N₂ Molecule, Zehra Nur Ozer, Hari Chaluvadi, Mevlut Dogan, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

We will present an experimental and theoretical investigation of triple differential cross sections for electron- impact ionization of nitrogen molecules at intermediate energies. A discussion of interference effects contained in the theoretical and experimental interference factors will be presented.


Theoretical And Experimental Study Of (E,2e) Ionization Of The Co₂ (1ΠG) Molecule At 250 Ev, Mevlut Dogan, Zehra Nur Ozer, Murat Yavuz, Osman Alwan, Adnan Naja, Boghos B. Joulakian, Esam S M Ali, Chuangang Ning, Don H. Madison Sep 2015

Theoretical And Experimental Study Of (E,2e) Ionization Of The Co₂ (1ΠG) Molecule At 250 Ev, Mevlut Dogan, Zehra Nur Ozer, Murat Yavuz, Osman Alwan, Adnan Naja, Boghos B. Joulakian, Esam S M Ali, Chuangang Ning, Don H. Madison

Physics Faculty Research & Creative Works

Triple differential cross sections (TDCSs) of the electron-impact ionization of carbon dioxide are measured in the coplanar asymmetric geometry, with incident electron energy value of 250eV, and ejected electron of 37eV. We will report the experimental results in comparison with the theoretical calculations of the M3DW and TCC (type 5) calculations.


Coplanar Asymmetric Angles And Symmetric Energy Sharing Triple Differential Cross Sections For 200 Ev Electron-Impact Ionization Of Ar (3p), Zehra Nur Ozer, Sadek M. Amami, Onur Varol, Murat Yavuz, Mevlut Dogan, Don H. Madison Sep 2015

Coplanar Asymmetric Angles And Symmetric Energy Sharing Triple Differential Cross Sections For 200 Ev Electron-Impact Ionization Of Ar (3p), Zehra Nur Ozer, Sadek M. Amami, Onur Varol, Murat Yavuz, Mevlut Dogan, Don H. Madison

Physics Faculty Research & Creative Works

We have measured triple differential cross sections (TDCSs) for electron-impact ionization of the 3p shell of Ar at 200 eV incident electron energy. The experiments have been performed in coplanar asymmetric energy sharing geometry. The experimental results are compared with the theoretical models of three body distorted wave (3DW) and distorted wave Born approximation (DWBA).


Clustering Data Of Mixed Categorical And Numerical Type With Unsupervised Feature Learning, Dao Lam, Mingzhen Wei, Donald C. Wunsch Sep 2015

Clustering Data Of Mixed Categorical And Numerical Type With Unsupervised Feature Learning, Dao Lam, Mingzhen Wei, Donald C. Wunsch

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Mixed-type categorical and numerical data are a challenge in many applications. This general area of mixed-type data is among the frontier areas, where computational intelligence approaches are often brittle compared with the capabilities of living creatures. In this paper, unsupervised feature learning (UFL) is applied to the mixed-type data to achieve a sparse representation, which makes it easier for clustering algorithms to separate the data. Unlike other UFL methods that work with homogeneous data, such as image and video data, the presented UFL works with the mixed-type data using fuzzy adaptive resonance theory (ART). UFL with fuzzy ART (UFLA) obtains …


Polyatomic Molecular Structure Retrieval Using Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, M. Sclafani, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert Sep 2015

Polyatomic Molecular Structure Retrieval Using Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, M. Sclafani, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert

Physics Faculty Research & Creative Works

Laser-induced electron diffraction is a developing dynamical imaging technique that is already able to probe molecular dynamics at few-femtosecond temporal resolutions and has the potential to reach the sub-femtosecond level. Here we provide the recipe for the extension of the technique to polyatomic molecules and we demonstrate the method by extracting the structure of aligned and anti-aligned acetylene (C₂H₂). We show that multiple bond lengths can be simultaneously imaged at high accuracy including elusive hydrogen containing bonds. Our results open the door to the investigation of larger complex molecules and the realization of a true molecular movie.


Evidence For Unnatural-Parity Contributions To Electron-Impact Ionization Of Laser-Aligned Atoms, G. S. J. Armstrong, J. Colgan, M. S. Pindzola, S. Amami, Don H. Madison, J. Pursehouse, K. L. Nixon, A. J. Murray Sep 2015

Evidence For Unnatural-Parity Contributions To Electron-Impact Ionization Of Laser-Aligned Atoms, G. S. J. Armstrong, J. Colgan, M. S. Pindzola, S. Amami, Don H. Madison, J. Pursehouse, K. L. Nixon, A. J. Murray

Physics Faculty Research & Creative Works

Recent measurements have examined the electron-impact ionization of excited-state laser-aligned Mg atoms. In this work we show that the ionization cross section arising from the geometry where the aligned atom is perpendicular to the scattering plane directly probes the unnatural parity contributions to the ionization amplitude. The contributions from natural parity partial waves cancel exactly in this geometry. Our calculations resolve the discrepancy between the nonzero measured cross sections in this plane and the zero cross section predicted by distorted-wave approaches. We demonstrate that this is a general feature of ionization from p-state targets by additional studies of ionization from …


Generalized Synthesis Of Eas [E = Fe, Co, Mn, Cr] Nanostructures And Investigating Their Morphology Evolution, Prachi Desai, Nikitaa Ashokan, Manashi Nath Sep 2015

Generalized Synthesis Of Eas [E = Fe, Co, Mn, Cr] Nanostructures And Investigating Their Morphology Evolution, Prachi Desai, Nikitaa Ashokan, Manashi Nath

Chemistry Faculty Research & Creative Works

This paper illustrates a novel route for the synthesis of nanostructured transition metal arsenides including those of FeAs, CoAs, MnAs, and CrAs through a generalized protocol. The key feature of the method is the use of one-step hot-injection and the clever use of a combination of precursors which are low-melting and highly reactive such as metal carbonyls and triphenylarsine in a solventless setup. This method also facilitates the formation of one-dimensional nanostructures as we move across the periodic table from CrAs to CoAs. The chemical basis of this reaction is simple redox chemistry between the transition metals, wherein the transition …


Vibrational Energy Levels Of The Simplest Criegee Intermediate (Ch₂Oo) From Full-Dimensional Lanczos, Mctdh, And Multimode Calculations, Hua-Gen Yu, Steve Alexandre Ndengué, Jun Li, Richard Dawes, Hua Guo Aug 2015

Vibrational Energy Levels Of The Simplest Criegee Intermediate (Ch₂Oo) From Full-Dimensional Lanczos, Mctdh, And Multimode Calculations, Hua-Gen Yu, Steve Alexandre Ndengué, Jun Li, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

Accurate vibrational energy levels of the simplest Criegee intermediate (CH2OO) were determined on a recently developed ab initio based nine-dimensional potential energy surface using three quantum mechanical methods. the first is the iterative Lanczos method using a conventional basis expansion with an exact Hamiltonian. the second and more efficient method is the multi-configurational time-dependent Hartree (MCTDH) method in which the potential energy surface is refit to conform to the sums-of-products requirement of MCTDH. Finally, the energy levels were computed with a vibrational self-consistent field/virtual configuration interaction method in MULTIMODE. the low-lying levels obtained from the three methods are …