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Articles 631 - 660 of 1762
Full-Text Articles in Physical Sciences and Mathematics
High-Order-Harmonic Generation Using Gas-Phase H₂O Molecules, Song-Feng Zhao, Cheng Jin, R. R. Lucchese, Anh-Thu Le, C. D. Lin
High-Order-Harmonic Generation Using Gas-Phase H₂O Molecules, Song-Feng Zhao, Cheng Jin, R. R. Lucchese, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
We investigate high-order-harmonic generation of isotropically distributed gas-phase H₂O molecules exposed to an intense laser field. The induced dipole of each individual molecule by the laser field is first calculated using the recently developed quantitative rescattering theory. In a thin medium, harmonic spectra generated coherently from all the molecules are then calculated by solving Maxwell's equation of propagation. By using accurate transition dipoles of H₂O, we show that the harmonics in the lower plateau region are quite different from models that employ the simpler strong-field approximation. We also examine the magnitude and phase of the harmonics and their dependence on …
Search For Gravitational Waves Associated With The August 2006 Timing Glitch Of The Vela Pulsar, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Search For Gravitational Waves Associated With The August 2006 Timing Glitch Of The Vela Pulsar, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
The physical mechanisms responsible for pulsar timing glitches are thought to excite quasinormal mode oscillations in their parent neutron star that couple to gravitational-wave emission. In August 2006, a timing glitch was observed in the radio emission of PSR B0833-45, the Vela pulsar. At the time of the glitch, the two colocated Hanford gravitational-wave detectors of the Laser Interferometer Gravitational-wave observatory (LIGO) were operational and taking data as part of the fifth LIGO science run (S5). We present the first direct search for the gravitational-wave emission associated with oscillations of the fundamental quadrupole mode excited by a pulsar timing glitch. …
Medium Propagation Effects In High-Order Harmonic Generation Of Ar And N₂, Cheng Jin, Anh-Thu Le, C. D. Lin
Medium Propagation Effects In High-Order Harmonic Generation Of Ar And N₂, Cheng Jin, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
We report theoretical calculations of high-order harmonic generation (HHG) by intense infrared lasers in atomic and molecular targets taking into account the macroscopic propagation of both fundamental and harmonic fields. On the examples of Ar and N₂, we demonstrate that these ab initio calculations are capable of accurately reproducing available experimental results with isotropic and aligned target media. We further present detailed analysis of HHG intensity and phase under various experimental conditions, in particular, as the wavelength of the driving laser changes. Most importantly, our results strongly support the factorization of HHG at the macroscopic level into a product of …
Observation Of Strong Resonant Behavior In The Inverse Photoelectron Spectroscopy Of Ce Oxide, James G. Tobin, Sw Yu, Brandon W. Chung, George Daniel Waddill, Laurent Claudius Duda, Joseph S. Nordgren
Observation Of Strong Resonant Behavior In The Inverse Photoelectron Spectroscopy Of Ce Oxide, James G. Tobin, Sw Yu, Brandon W. Chung, George Daniel Waddill, Laurent Claudius Duda, Joseph S. Nordgren
Physics Faculty Research & Creative Works
X-ray emission spectroscopy and resonant inverse photoelectron spectroscopy (RIPES) have been used to investigate the photon emission associated with the Ce 3d5/2 and Ce 3d3/2 thresholds. Strong resonant behavior has been observed in the RIPES of a Ce oxide near the 5/2 and 3/2 edges.
Neutrino Mass Constraint From The Sloan Digital Sky Survey Power Spectrum Of Luminous Red Galaxies And Perturbation Theory, Shun Saito, Masahiro Takada, Atsushi Taruya
Neutrino Mass Constraint From The Sloan Digital Sky Survey Power Spectrum Of Luminous Red Galaxies And Perturbation Theory, Shun Saito, Masahiro Takada, Atsushi Taruya
Physics Faculty Research & Creative Works
We compare the model power spectrum, computed based on perturbation theory, with the power spectrum of luminous red galaxies (LRG) measured from the Sloan Digital Sky Survey Data Release 7 catalog, assuming a flat, cold dark matter-dominated cosmology. The model includes the effects of massive neutrinos, nonlinear matter clustering and nonlinear, scale-dependent galaxy bias in a self-consistent manner. We first test the accuracy of the perturbation theory model by comparing the model predictions with the halo power spectrum in real- and redshift-space, measured from 70 simulation realizations for a cold dark matter model without massive neutrinos. We show that the …
Generation Of High-Energy Photons With Large Orbital Angular Momentum By Compton Backscattering, Ulrich D. Jentschura, Valery G. Serbo
Generation Of High-Energy Photons With Large Orbital Angular Momentum By Compton Backscattering, Ulrich D. Jentschura, Valery G. Serbo
Physics Faculty Research & Creative Works
Usually, photons are described by plane waves with a definite 4-momentum. In addition to plane-wave photons, "twisted photons" have recently entered the field of modern laser optics; these are coherent superpositions of plane waves with a defined projection ℏm of the orbital angular momentum onto the propagation axis, where m is an integer. In this Letter, we show that it is possible to produce high-energy twisted photons by Compton backscattering of twisted laser photons off ultrarelativistic electrons. Such photons may be of interest for experiments related to the excitation and disintegration of atoms and nuclei, and for studying the …
Generalized Contact Process With Two Symmetric Absorbing States In Two Dimensions, Man Young Lee, Thomas Vojta
Generalized Contact Process With Two Symmetric Absorbing States In Two Dimensions, Man Young Lee, Thomas Vojta
Physics Faculty Research & Creative Works
We explore the two-dimensional generalized contact process with two absorbing states by means of large-scale Monte-Carlo simulations. In part of the phase diagram, an infinitesimal creation rate of active sites between inactive domains is sufficient to take the system from the inactive phase to the active phase. The system, therefore, displays two different nonequilibrium phase transitions. The critical behavior of the generic transition is compatible with the generalized voter universality class, implying that the symmetry-breaking and absorbing transitions coincide. In contrast, the transition at zero domain-boundary activation rate is not critical.
Dynamical (E, 2e) Studies Using Tetrahydrofuran As A Dna Analogue, Christopher J. Colyer, Susan M. Bellm, G. Friedrich Hanne, Ola A. Al-Hagan, Don H. Madison, Chuangang Ning, B. Lohmann
Dynamical (E, 2e) Studies Using Tetrahydrofuran As A Dna Analogue, Christopher J. Colyer, Susan M. Bellm, G. Friedrich Hanne, Ola A. Al-Hagan, Don H. Madison, Chuangang Ning, B. Lohmann
Physics Faculty Research & Creative Works
We present dynamical (e, 2e) measurements for the electron impact ionization of formic acid and tetrahydrofuran molecules performed under similar kinematics. The experiments have been performed in the coplanar asymmetric geometry for a range of momentum transfers, at an incident electron energy of 250 eV and with an ejected electron energy of 10eV. The experimental results are compared with theoretical calculations carried out using the molecular 3-body distorted wave (M3DW) model.
Non-Gaussian Error Contribution To Likelihood Analysis Of The Matter Power Spectrum, Ryuichi Takahashi, Naoki Yoshida, Masahiro Takada, Takahiko Matsubara, Naoshi Sugiyama, Issha Kayo, Takahiro Nishimichi, Shun Saito, Atsushi Taruya
Non-Gaussian Error Contribution To Likelihood Analysis Of The Matter Power Spectrum, Ryuichi Takahashi, Naoki Yoshida, Masahiro Takada, Takahiko Matsubara, Naoshi Sugiyama, Issha Kayo, Takahiro Nishimichi, Shun Saito, Atsushi Taruya
Physics Faculty Research & Creative Works
We study the sample variance of the matter power spectrum for the standard Λ cold dark matter universe. We use a total of 5000 cosmological N-body simulations to study in detail the distribution of best-fit cosmological parameters and the baryon acoustic peak positions. The obtained distribution is compared with the results from the Fisher matrix analysis with and without including non-Gaussian errors. For the Fisher matrix analysis, we compute the derivatives of the matter power spectrum with respect to cosmological parameters using directly full nonlinear simulations. We show that the non-Gaussian errors increase the unmarginalized errors by up to a …
Detailed Mapping Of The Local Ir⁴⁺ Dimers Through The Metal-Insulator Transitions Of Cuir₂S₄ Thiospinel By X-Ray Atomic Pair Distribution Function Measurements, Emil S. Bozin, Ahmad S. Masadeh, Yew San Hor, J. F. Mitchell, Simon J. Billinge
Detailed Mapping Of The Local Ir⁴⁺ Dimers Through The Metal-Insulator Transitions Of Cuir₂S₄ Thiospinel By X-Ray Atomic Pair Distribution Function Measurements, Emil S. Bozin, Ahmad S. Masadeh, Yew San Hor, J. F. Mitchell, Simon J. Billinge
Physics Faculty Research & Creative Works
The evolution of the short-range structural signature of the Ir 4+ dimer state in CuIr2S4 thiospinel has been studied across the metal-insulator phase transitions as the metallic state is induced by temperature, Cr doping, and x-ray fluence. An atomic pair distribution function (PDF) approach reveals that there are no local dimers that survive into the metallic phase when this is invoked by temperature and doping. The PDF shows Ir4+ dimers when they exist, regardless of whether or not they are long-range ordered. At 100 K, exposure to a 98 keV x-ray beam melts the long-range dimer …
Differential Positron And Electron Ionization Studies: How A Plus Or Minus Sign Makes A Difference, Robert D. Dubois
Differential Positron And Electron Ionization Studies: How A Plus Or Minus Sign Makes A Difference, Robert D. Dubois
Physics Faculty Research & Creative Works
Doubly and triply differential data for single ionization of argon, neon and molecular nitrogen have been measured for positron and electron impact energies of 200, 250, and 500 eV. Ratios of triply to doubly differential ionization yields as functions of the projectile scattering angle and energy loss are compared in order to investigate differences associated with the sign of the projectile charge. for all three systems, systematic differences are observed in the relative contributions of binary interactions. These differences are shown to increase with increasing scattering angle. Nearly identical recoil intensities are found for positron and electron impact ionization of …
Momentum Spectra Of Electrons Rescattered From Rare-Gas Targets Following Their Extraction By One- And Two-Color Femtosecond Laser Pulses, D. Ray, Z. Chen, S. De, W. Cao, I. V. Litvinyuk, Anh-Thu Le, C. D. Lin, M. F. Kling, C. L. Cocke
Momentum Spectra Of Electrons Rescattered From Rare-Gas Targets Following Their Extraction By One- And Two-Color Femtosecond Laser Pulses, D. Ray, Z. Chen, S. De, W. Cao, I. V. Litvinyuk, Anh-Thu Le, C. D. Lin, M. F. Kling, C. L. Cocke
Physics Faculty Research & Creative Works
We have used velocity-map imaging to measure the three-dimensional momenta of electrons rescattered from Xe and Ar following the liberation of the electrons from these atoms by 45 fs, 800 nm intense laser pulses. Strong structure in the rescattering region is observed in both angle and energy, and is interpreted in terms of quantitative rescattering (QRS) theory. Momentum images have also been taken with two-color (800 nm + 400 nm) pulses on Xe targets. A strong dependence of the spectra on the relative phase of the two colors is observed in the rescattering region. Interpretation of the phase dependence using …
Scattering-Angle Dependence Of Doubly Differential Cross Sections For Fragmentation Of H₂ By Proton Impact, Kisra N. Egodapitiya, Sachin D. Sharma, Aaron C. Laforge, Michael Schulz
Scattering-Angle Dependence Of Doubly Differential Cross Sections For Fragmentation Of H₂ By Proton Impact, Kisra N. Egodapitiya, Sachin D. Sharma, Aaron C. Laforge, Michael Schulz
Physics Faculty Research & Creative Works
We have measured double differential cross sections (DDCS) for proton fragment formation for fixed projectile energy losses as a function of projectile scattering angle in 75 keV p + H2 collisions. An oscillating pattern was observed in the angular dependence of the DDCS with a frequency about twice as large as what we found earlier for nondissociative ionization. Possible origins for this frequency doubling are discussed.
Direct Observation Of Spin-Polarized Surface States In The Parent Compound Of A Topological Insulator Using Spin- And Angle-Resolved Photoemission Spectroscopy In A Mott-Polarimetry Mode, David Hsieh, Lewis Andrew Wray, Dong Qian, Yuqi Xia, Jan Hugo Dil, Fabian Meier, Luc Patthey, Jurg Osterwalder, Gustav Bihlmayer, Yew San Hor, Robert Joseph Cava, Md Zahid Hasan
Direct Observation Of Spin-Polarized Surface States In The Parent Compound Of A Topological Insulator Using Spin- And Angle-Resolved Photoemission Spectroscopy In A Mott-Polarimetry Mode, David Hsieh, Lewis Andrew Wray, Dong Qian, Yuqi Xia, Jan Hugo Dil, Fabian Meier, Luc Patthey, Jurg Osterwalder, Gustav Bihlmayer, Yew San Hor, Robert Joseph Cava, Md Zahid Hasan
Physics Faculty Research & Creative Works
We report high-resolution spin-resolved photoemission spectroscopy (spin-ARPES) measurements on the parent compound Sb of the recently discovered three-dimensional topological insulator Bi1-xSbx (Hsieh et al 2008 Nature 452 970, Hsieh et al 2009 Science 323 919). By modulating the incident photon energy, we are able to map both the bulk and the (111) surface band structure, from which we directly demonstrate that the surface bands are spin polarized by the spin-orbit interaction and connect the bulk valence and conduction bands in a topologically non-trivial way. A unique asymmetric Dirac surface state gives rise to a k-splitting of its …
Reaction Dynamics In Double Ionization Of Helium By Electron Impact, Marcelo F. Ciappina, Michael Schulz, Tom Kirchner
Reaction Dynamics In Double Ionization Of Helium By Electron Impact, Marcelo F. Ciappina, Michael Schulz, Tom Kirchner
Physics Faculty Research & Creative Works
We present theoretical fully differential cross sections (FDCS) for double ionization of helium by 500 eV and 2 keV electron impact. Contributions from various reaction mechanisms to the FDCS were calculated separately and compared to experimental data. Our theoretical methods are based on the first Born approximation. Higher-order effects are incorporated using the Monte Carlo event generator technique. Earlier, we successfully applied this approach to double ionization by ion impact, and in the work reported here it is extended to electron impact. We demonstrate that at 500 eV impact energy, double ionization is dominated by higher-order mechanisms. Even at 2 …
Large Group Delay In A Microwave Metamaterial Analog Of Electromagnetically Induced Transparency, Lei Zhang, Philippe Tassin, Thomas Koschny, Cihan Kurter, Steven M. Anlage, C. M. Soukoulis
Large Group Delay In A Microwave Metamaterial Analog Of Electromagnetically Induced Transparency, Lei Zhang, Philippe Tassin, Thomas Koschny, Cihan Kurter, Steven M. Anlage, C. M. Soukoulis
Physics Faculty Research & Creative Works
We report on our experimental work concerning a planar metamaterial exhibiting classical electromagnetically induced transparency (EIT). Using a structure with two mirrored split-ring resonators as the dark element and a cut wire as the radiative element, we demonstrate that an EIT-like resonance can be achieved without breaking the symmetry of the structure. The mirror symmetry of the metamaterial's structural element results in a selection rule inhibiting magnetic dipole radiation for the dark element, and the increased quality factor leads to low absorption (<10%) and large group index (of the order of 30).
Stability And Charge Transfer Levels Of Extrinsic Defects In Linbo₃, Haixuan Xu, Aleksandr V. Chernatynskiy, Donghwa Lee, Susan Sinnott, Venkatraman Gopalan, Volkmar Dierolf, Simon R. Phillpot
Stability And Charge Transfer Levels Of Extrinsic Defects In Linbo₃, Haixuan Xu, Aleksandr V. Chernatynskiy, Donghwa Lee, Susan Sinnott, Venkatraman Gopalan, Volkmar Dierolf, Simon R. Phillpot
Physics Faculty Research & Creative Works
The technologically important incorporation of extrinsic defects (Mg2+, Fe2+, Fe3+, Er3+, and Nd3+) in LiNbO3 is investigated using density-functional theory combined with thermodynamic calculations. Defect energies, the charge compensation mechanisms, and charge transfer levels, are determined for congruent and stoichiometric compositions. In general, under congruent (Nb2O5-rich) conditions impurities occupy lithium sites, compensated by lithium vacancies. Under stoichiometric (Li2O-rich) conditions, impurities occupy both lithium and niobium sites. The effects of the concentration of Mg on the dominant defect and site occupancy are analyzed. In …
Search For Gravitational Waves From Compact Binary Coalescence In Ligo And Virgo Data From S5 And Vsr1, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Search For Gravitational Waves From Compact Binary Coalescence In Ligo And Virgo Data From S5 And Vsr1, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We report the results of the first search for gravitational waves from compact binary coalescence using data from the Laser Interferometer Gravitational-Wave Observatory and Virgo detectors. Five months of data were collected during the Laser Interferometer Gravitational-Wave Observatory's S5 and Virgo's VSR1 science runs. The search focused on signals from binary mergers with a total mass between 2 and 35M⊙. No gravitational waves are identified. The cumulative 90%-confidence upper limits on the rate of compact binary coalescence are calculated for nonspinning binary neutron stars, black hole-neutron star systems, and binary black holes to be 8.7 x 10- …
Anderson Localization As Position-Dependent Diffusion In Disordered Waveguides, Ben Payne, Alexey Yamilov, Sergey E. Skipetrov
Anderson Localization As Position-Dependent Diffusion In Disordered Waveguides, Ben Payne, Alexey Yamilov, Sergey E. Skipetrov
Physics Faculty Research & Creative Works
We show that the recently developed self-consistent theory of Anderson localization with a position-dependent diffusion coefficient is in quantitative agreement with the supersymmetry approach up to terms of the order of 1 / g20 (with g0 the dimensionless conductance in the absence of interference effects) and with large-scale ab initio simulations of the classical wave transport in disordered waveguides, at least for g0 ≥ 0.5. In the latter case, agreement is found even in the presence of absorption. Our numerical results confirm that in open disordered media, the onset of Anderson localization can be viewed as …
Dynamical Conductivity At The Dirty Superconductor-Metal Quantum Phase Transition, Adrian Del Maestro, Bernd Rosenow, Jose A. Hoyos, Thomas Vojta
Dynamical Conductivity At The Dirty Superconductor-Metal Quantum Phase Transition, Adrian Del Maestro, Bernd Rosenow, Jose A. Hoyos, Thomas Vojta
Physics Faculty Research & Creative Works
We study the transport properties of ultrathin disordered nanowires in the neighborhood of the superconductor-metal quantum phase transition. To this end we combine numerical calculations with analytical strong-disorder renormalization group results. The quantum critical conductivity at zero temperature diverges logarithmically as a function of frequency. In the metallic phase, it obeys activated scaling associated with an infinite-randomness quantum critical point. We extend the scaling theory to higher dimensions and discuss implications for experiments.
Erratum: Determination Of Structure Parameters In Strong-Field Tunneling Ionization Theory Of Molecules (Physical Review A (2010) 81 (033423)), Song-Feng Zhao, Cheng Jin, Anh-Thu Le, T. F. Jiang, C. D. Lin
Erratum: Determination Of Structure Parameters In Strong-Field Tunneling Ionization Theory Of Molecules (Physical Review A (2010) 81 (033423)), Song-Feng Zhao, Cheng Jin, Anh-Thu Le, T. F. Jiang, C. D. Lin
Physics Faculty Research & Creative Works
There are several errors in Tables V and VI of our article. In Table V, the C2m of the HOMO-1 (1π) of CO molecule should be 0.014. In Table VI, the binding energies of 2pπg and 2pπu of H₂⁺ should be 0.2267 and 0.4288, respectively.
Evaluation Of Computational Techniques For Solving The Boltzmann Transport Equation For Lattice Thermal Conductivity Calculations, Aleksandr V. Chernatynskiy, Simon R. Phillpot
Evaluation Of Computational Techniques For Solving The Boltzmann Transport Equation For Lattice Thermal Conductivity Calculations, Aleksandr V. Chernatynskiy, Simon R. Phillpot
Physics Faculty Research & Creative Works
Three methods for computing thermal conductivity from lattice dynamics (the iterative method, the variational method, and the relaxation-time approximation) are compared for the prototypical case of solid argon. The iterative method is found to produce results in close agreement with Green-Kubo molecular-dynamics simulations, a formally correct method for computing thermal conductivity. The variational method and relaxation-time approximation are found to underestimate the thermal conductivity. The relationship among the methods is established; a combination of the iterative and variational methods is found to have a fastest convergence. Formal convergence of the iterative method is demonstrated and a simple mixing rule is …
Baryon Acoustic Oscillations In 2d: Modeling Redshift-Space Power Spectrum From Perturbation Theory, Atsushi Taruya, Takahiro Nishimichi, Shun Saito
Baryon Acoustic Oscillations In 2d: Modeling Redshift-Space Power Spectrum From Perturbation Theory, Atsushi Taruya, Takahiro Nishimichi, Shun Saito
Physics Faculty Research & Creative Works
We present an improved prescription for the matter power spectrum in redshift space taking proper account of both nonlinear gravitational clustering and redshift distortion, which are of particular importance for accurately modeling baryon acoustic oscillations (BAOs). Contrary to the models of redshift distortion phenomenologically introduced but frequently used in the literature, the new model includes the corrections arising from the nonlinear coupling between the density and velocity fields associated with two competitive effects of redshift distortion, i.e., Kaiser and Finger-of-God effects. Based on the improved treatment of perturbation theory for gravitational clustering, we compare our model predictions with the monopole …
Relation Between Transmission And Energy Stored In Random Media With Gain, Ben Payne, Jonathan Andreasen, Hui Cao, Alexey Yamilov
Relation Between Transmission And Energy Stored In Random Media With Gain, Ben Payne, Jonathan Andreasen, Hui Cao, Alexey Yamilov
Physics Faculty Research & Creative Works
In this work, we investigate a possibility of using the ratio between optical transmission, T, and energy stored inside the system, E, as a quantitative measure of the enhanced mesoscopic corrections to diffusive transport of light through a random medium with gain. We obtain an expression for T/E as a function of amplification strength in the diffusive approximation and show that it does not a have tendency to diverge when the threshold for random lasing is approached, as both T and E do. Furthermore, we find that a change in T/E signifies a change in the electric field distribution inside …
Dynamical (E, 2e) Studies Using Tetrahydrofuran As A Dna Analog, Christopher J. Colyer, Susan M. Bellm, B. Lohmann, G. Friedrich Hanne, Ola A. Al-Hagan, Don H. Madison, Chuangang Ning
Dynamical (E, 2e) Studies Using Tetrahydrofuran As A Dna Analog, Christopher J. Colyer, Susan M. Bellm, B. Lohmann, G. Friedrich Hanne, Ola A. Al-Hagan, Don H. Madison, Chuangang Ning
Physics Faculty Research & Creative Works
Triple differential cross sections for the electron-impact ionization of the outer valence orbital of tetrahydrofuran have been measured using the (e, 2e) technique. The measurements have been performed with coplanar asymmetric kinematics, at an incident electron energy of 250 eV and at an ejected electron energy of 10 eV, over a range of momentum transfers. The experimental results are compared with theoretical calculations carried out using the molecular three-body distorted wave model. The results obtained are important for gaining an understanding of electron driven processes at a molecular level and for modeling energy deposition in living tissue.
Tracing Multiple Scattering Patterns In Absolute (E, 2e) Cross Sections For H₂ And He Over A 4Π Solid Angle, Xueguang Ren, Arne Senftleben, Thomas Pflüger, Alexander Dorn, James Colgan, Michael S. Pindzola, Ola A. Al-Hagan, Don H. Madison, Igor Bray, Dmitry V. Fursa, Joachim Hermann Ullrich
Tracing Multiple Scattering Patterns In Absolute (E, 2e) Cross Sections For H₂ And He Over A 4Π Solid Angle, Xueguang Ren, Arne Senftleben, Thomas Pflüger, Alexander Dorn, James Colgan, Michael S. Pindzola, Ola A. Al-Hagan, Don H. Madison, Igor Bray, Dmitry V. Fursa, Joachim Hermann Ullrich
Physics Faculty Research & Creative Works
Absolutely normalized (e,2e) measurements for H2 and He covering the full solid angle of one ejected electron are presented for 16 eV sum energy of both final state continuum electrons. For both targets rich cross-section structures in addition to the binary and recoil lobes are identified and studied as a function of the fixed electron's emission angle and the energy sharing among both electrons. For H2 their behavior is consistent with multiple scattering of the projectile as discussed before. For He the binary and recoil lobes are significantly larger than for H2 and partly cover the multiple …
First Search For Gravitational Waves From The Youngest Known Neutron Star, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
First Search For Gravitational Waves From The Youngest Known Neutron Star, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present a search for periodic gravitational waves from the neutron star in the supernova remnant Cassiopeia A. The search coherently analyzes data in a 12 day interval taken from the fifth science run of the Laser Interferometer Gravitational-Wave Observatory. It searches gravitational-wave frequencies from 100 to 300 Hz and covers a wide range of first and second frequency derivatives appropriate for the age of the remnant and for different spin-down mechanisms. No gravitational-wave signal was detected. Within the range of search frequencies, we set 95% confidence upper limits of (0.7-1.2) x 10-24 on the intrinsic gravitational-wave strain, (0.4-4) …
Effect Of An Improved Molecular Potential On Strong-Field Tunneling Ionization Of Molecules, Song-Feng Zhao, Cheng Jin, Anh-Thu Le, C. D. Lin
Effect Of An Improved Molecular Potential On Strong-Field Tunneling Ionization Of Molecules, Song-Feng Zhao, Cheng Jin, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
We study the effect of one-electron model potentials on the tunneling ionization rates of molecules in strong fields. By including electron correlation using the modified Leeuwen-Baerends (LB α) model, the binding energies of outer shells of molecules are significantly improved. However, we show that the tunneling ionization rates from the LB α do not differ much from the earlier calculations [Phys. Rev. A 81, 033423 (2010)], in which the local correlation potential was neglected.
Self-Imaging Of Molecules From Diffraction Spectra By Laser-Induced Rescattering Electrons, Junliang Xu, Zhangjin Chen, Anh-Thu Le, C. D. Lin
Self-Imaging Of Molecules From Diffraction Spectra By Laser-Induced Rescattering Electrons, Junliang Xu, Zhangjin Chen, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
We study high-energy angle-resolved photoelectron spectra of molecules in strong fields. In an oscillating laser electric field, electrons released earlier in the pulse may return to recollide with the target ion, in a process similar to scattering by laboratory prepared electrons. If midinfrared lasers are used, we show that the images generated by the returning electrons are similar to images observed in typical gas-phase electron diffraction (GED). These spectra can be used to retrieve the positions of atoms in a molecule as in GED. Since infrared laser pulses of durations of a few femtoseconds are already available today, the study …
Influence Of Ambient Temperature On The Pm Emissions From A Gas Turbine Engine, Donald E. Hagen, Prem Lobo, Philip D. Whitefield, Max B. Trueblood
Influence Of Ambient Temperature On The Pm Emissions From A Gas Turbine Engine, Donald E. Hagen, Prem Lobo, Philip D. Whitefield, Max B. Trueblood
Physics Faculty Research & Creative Works
During Project AAFEX, PM emissions measurements were conducted on a CFM56-2C1 gas turbine engine in January 2009 in Palmdale CA. The engine was mounted on a NASA DC-8 aircraft, which was parked on the runway, and emission samples were extracted at the engine exit plane (1m), in the near field (30m), and in the advected plume (145m). The engine was operated at several power levels, and burned several fuels: JP-8, a Fischer-Tropsch fuel derived from natural gas (FT1), and a second Fischer-Tropsch fuel derived from gasified coal (FT2). In addition to these fuels, 50:50 blends of the Fischer-Tropsch fuels and …