Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Ionization (11)
- Atoms (5)
- Impact Ionization (5)
- Molecules (5)
- Electron Impact-Ionization (4)
-
- Electron Scattering (4)
- Electron impact-ionization (4)
- Electrons (4)
- Electrodynamics (3)
- Photons (3)
- Quantum Electrodynamics (3)
- Quantum Electronics (3)
- Quantum Theory (3)
- Triple Differential Cross Sections (3)
- Triple differential cross sections (3)
- Born approximation (2)
- Critical State (2)
- Distorted wave Born approximation (2)
- Distortion (waves) (2)
- Electron Diffraction (2)
- Electron energy levels (2)
- Electron scattering (2)
- Geometry (2)
- Hermitians (2)
- Highest Occupied Molecular Orbital (2)
- Hydrogen (2)
- Impact ionization (2)
- Incident electrons (2)
- Molecular Orbitals (2)
- Optical Waveguide Arrays (2)
Articles 31 - 48 of 48
Full-Text Articles in Physics
Target Electron Ionization In Li²⁺-L-Li Collisions: A Multi-Electron Perspective, Maciej Dominik Piewanowski, Laszlo Gulyas, Marko W. Horbatsch, Johannes Goullon, Natalia Ferreira, Renate Hubele, Vitor L B D De Jesus, H. Lindenblatt, Katharina R. Schneider, Michael Schulz, Michael Schuricke, Z. Song, Shaofeng Zhang, Daniel Fischer, Tom Kirchner
Target Electron Ionization In Li²⁺-L-Li Collisions: A Multi-Electron Perspective, Maciej Dominik Piewanowski, Laszlo Gulyas, Marko W. Horbatsch, Johannes Goullon, Natalia Ferreira, Renate Hubele, Vitor L B D De Jesus, H. Lindenblatt, Katharina R. Schneider, Michael Schulz, Michael Schuricke, Z. Song, Shaofeng Zhang, Daniel Fischer, Tom Kirchner
Physics Faculty Research & Creative Works
Target electron removal in Li2+-Li collisions at 2290 keV/amu is studied experimentally and theoretically for ground and excited lithium target configurations. It is shown that in outer-shell ionization a single-electron process plays the dominant part. However, the K-shell ionization results are more difficult to interpret. According to our calculations, the process is shown to be strongly single-particle like. On one hand, a high resemblance between theoretical single-particle ionization and exclusive inner-shell ionization is demonstrated, and contributions from multi-electron processes are found to be weak. On the other hand, it is indicated by the discrepancy between experimental and single-particle …
Classical Description Of H(1s) And H* (N=2) For Cross-Section Calculations Relevant To Charge-Exchange Diagnostics, N. D. Cariatore, Sebastian Otranto, Ronald E. Olson
Classical Description Of H(1s) And H* (N=2) For Cross-Section Calculations Relevant To Charge-Exchange Diagnostics, N. D. Cariatore, Sebastian Otranto, Ronald E. Olson
Physics Faculty Research & Creative Works
In this work, we introduce a classical trajectory Monte Carlo (CTMC) methodology, specially conceived to provide a more accurate representation of charge-exchange processes between highly charged ions and H(1s) and H* (n=2). These processes are of particular relevance in power fusion reactor programs, for which charge-exchange spectroscopy has become a useful plasma diagnostics tool. To test the methodology, electron-capture reactions from these targets by C6+,N7+, and O8+ are studied at impact energies in the 10-150keV/amu range. State-selective cross sections are contrasted with those predicted by the standard microcanonical formulation of the CTMC method, the CTMC …
Negative-Quench-Induced Excitation Dynamics For Ultracold Bosons In One-Dimensional Lattices, Simeon I. Mistakidis, L. Cao, P. Schmelcher
Negative-Quench-Induced Excitation Dynamics For Ultracold Bosons In One-Dimensional Lattices, Simeon I. Mistakidis, L. Cao, P. Schmelcher
Physics Faculty Research & Creative Works
The Nonequilibrium Dynamics Following A Quench Of Strongly Repulsive Bosonic Ensembles In One-Dimensional Finite Lattices Is Investigated By Employing Interaction Quenches And/or A Ramp Of The Lattice Potential. Both Sudden And Time-Dependent Quenches Are Analyzed In Detail. For The Case Of Interaction Quenches We Address The Transition From The Strong Repulsive To The Weakly Interacting Regime, Suppressing In This Manner The Heating Of The System. The Excitation Modes Such As The Cradle Process And The Local Breathing Mode Are Examined Via Local Density Observables. In Particular, The Cradle Mode Is Inherently Related To The Initial Delocalization And, Following A Negative …
Directed Search For Gravitational Waves From Scorpius X-1 With Initial Ligo Data, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Directed Search For Gravitational Waves From Scorpius X-1 With Initial Ligo Data, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present results of a search for continuously emitted gravitational radiation, directed at the brightest low-mass x-ray binary, Scorpius X-1. Our semicoherent analysis covers 10 days of LIGO S5 data ranging from 50-550 Hz, and performs an incoherent sum of coherent F-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1; …
Kinematically Complete Study Of Low-Energy Electron-Impact Ionization Of Neon: Internormalized Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Oleg Zatsarinny, Thomas Pflüger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn
Kinematically Complete Study Of Low-Energy Electron-Impact Ionization Of Neon: Internormalized Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Oleg Zatsarinny, Thomas Pflüger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn
Physics Faculty Research & Creative Works
Low-energy (E0 0=65eV) electron-impact single ionization of Ne (2p) has been investigated to thoroughly test state-of-the-art theoretical approaches. The experimental data were measured using a reaction microscope, which can cover nearly the entire 4π solid angle for the secondary electron emission energies ranging from 2 to 8 eV, and projectile scattering angles ranging from 8.5⁰ to 20.0⁰. The experimental triple-differential cross sections are internormalized across all measured scattering angles and ejected energies. The experimental data are compared to predictions from a hybrid second-order distorted-wave Born plus R-matrix approach, the distorted-wave Born approximation with the inclusion of postcollision interaction (PCI), …
Symmetric Solitonic Excitations Of The (1 + 1)-Dimensional Abelian-Higgs Classical Vacuum, F. K. Diakonos, Garyfallia C. Katsimiga, X. N. Maintas, C. E. Tsagkarakis
Symmetric Solitonic Excitations Of The (1 + 1)-Dimensional Abelian-Higgs Classical Vacuum, F. K. Diakonos, Garyfallia C. Katsimiga, X. N. Maintas, C. E. Tsagkarakis
Physics Faculty Research & Creative Works
We study the classical dynamics of the Abelian-Higgs model in (1 + 1) space-time dimensions for the case of strongly broken gauge symmetry. In this limit the wells of the potential are almost harmonic and sufficiently deep, presenting a scenario far from the associated critical point. Using a multiscale perturbation expansion, the equations of motion for the fields are reduced to a system of coupled nonlinear Schrödinger equations. Exact solutions of the latter are used to obtain approximate analytical solutions for the full dynamics of both the gauge and Higgs field in the form of oscillons and oscillating kinks. Numerical …
Benchmarking Accurate Spectral Phase Retrieval Of Single Attosecond Pulses, Hui Wei, Anh-Thu Le, Toru Morishita, Chao Yu, C. D. Lin
Benchmarking Accurate Spectral Phase Retrieval Of Single Attosecond Pulses, Hui Wei, Anh-Thu Le, Toru Morishita, Chao Yu, C. D. Lin
Physics Faculty Research & Creative Works
A single extreme-ultraviolet (XUV) attosecond pulse or pulse train in the time domain is fully characterized if its spectral amplitude and phase are both determined. The spectral amplitude can be easily obtained from photoionization of simple atoms where accurate photoionization cross sections have been measured from, e.g., synchrotron radiations. To determine the spectral phase, at present the standard method is to carry out XUV photoionization in the presence of a dressing infrared (IR) laser. In this work, we examine the accuracy of current phase retrieval methods (PROOF and iPROOF) where the dressing IR is relatively weak such that photoelectron spectra …
Gravitational Correction To Vacuum Polarization, Ulrich D. Jentschura
Gravitational Correction To Vacuum Polarization, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
We consider the gravitational correction to (electronic) vacuum polarization in the presence of a gravitational background field. The Dirac propagators for the virtual fermions are modified to include the leading gravitational correction (potential term) which corresponds to a coordinate-dependent fermion mass. The mass term is assumed to be uniform over a length scale commensurate with the virtual electron-positron pair. The on-mass shell renormalization condition ensures that the gravitational correction vanishes on the mass shell of the photon, i.e., the speed of light is unaffected by the quantum field theoretical loop correction, in full agreement with the equivalence principle. Nontrivial corrections …
Nodal To Nodeless Superconducting Energy-Gap Structure Change Concomitant With Fermi-Surface Reconstruction In The Heavy-Fermion Compound Cecoin₅, Hyunsoo Kim, M. A. Tanatar, R. Flint, C. Petrovic, Rongwei Hu, B. D. White, I. K. Lum, M. B. Maple, R. Prozorov
Nodal To Nodeless Superconducting Energy-Gap Structure Change Concomitant With Fermi-Surface Reconstruction In The Heavy-Fermion Compound Cecoin₅, Hyunsoo Kim, M. A. Tanatar, R. Flint, C. Petrovic, Rongwei Hu, B. D. White, I. K. Lum, M. B. Maple, R. Prozorov
Physics Faculty Research & Creative Works
The London penetration depth λ(T) was measured in single crystals of Ce1-xRxCoIn5, R = La, Nd, and Yb down to Tmin ≈ 50mK (Tc/Tmin ∼ 50) using a tunnel-diode resonator. In the cleanest samples Δλ(T) is best described by the power law Δλ(T) α Tn, with n ∼ 1, consistent with the existence of line nodes in the superconducting gap. Substitutions of Ce with La, Nd, and Yb lead to similar monotonic suppressions of Tc; however, the effects on Δλ(T) differ. While La and Nd substitution leads to …
Narrow-Band Search Of Continuous Gravitational-Wave Signals From Crab And Vela Pulsars In Virgo Vsr4 Data, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Narrow-Band Search Of Continuous Gravitational-Wave Signals From Crab And Vela Pulsars In Virgo Vsr4 Data, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
In this paper we present the results of a coherent narrow-band search for continuous gravitational-wave signals from the Crab and Vela pulsars conducted on Virgo VSR4 data. In order to take into account a possible small mismatch between the gravitational-wave frequency and two times the star rotation frequency, inferred from measurement of the electromagnetic pulse rate, a range of 0.02 Hz around two times the star rotational frequency has been searched for both the pulsars. No evidence for a signal has been found and 95% confidence level upper limits have been computed assuming both that polarization parameters are completely unknown …
Searching For Stochastic Gravitational Waves Using Data From The Two Colocated Ligo Hanford Detectors, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Searching For Stochastic Gravitational Waves Using Data From The Two Colocated Ligo Hanford Detectors, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
Searches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a colocated detector pair is more sensitive to a gravitational-wave background than a noncolocated detector pair. However, colocated detectors are also expected to suffer from correlated noise from instrumental and environmental effects that could contaminate the measurement of the background. Hence, methods to identify and mitigate the effects of correlated noise are necessary to achieve the …
Computational Discovery Of Lanthanide Doped And Co-Doped Y₃Al₅O₁₂ For Optoelectronic Applications, Kamal Kumar Choudhary, Aleksandr V. Chernatynskiy, Kiran Mathew, Eric W. Bucholz, Simon R. Phillpot, Susan Sinnott, Richard G. Hennig
Computational Discovery Of Lanthanide Doped And Co-Doped Y₃Al₅O₁₂ For Optoelectronic Applications, Kamal Kumar Choudhary, Aleksandr V. Chernatynskiy, Kiran Mathew, Eric W. Bucholz, Simon R. Phillpot, Susan Sinnott, Richard G. Hennig
Physics Faculty Research & Creative Works
We systematically elucidate the optoelectronic properties of rare-earth doped and Ce co-doped yttrium aluminum garnet (YAG) using hybrid exchange-correlation functional based density functional theory. The predicted optical transitions agree with the experimental observations for single doped Ce:YAG, Pr:YAG, and co-doped Er,Ce:YAG. We find that co-doping of Ce-doped YAG with any lanthanide except Eu and Lu lowers the transition energies; we attribute this behavior to the lanthanide-induced change in bonding environment of the dopant atoms. Furthermore, we find infrared transitions only in case of the Er, Tb, and Tm co-doped Ce:YAG and suggest Tm,Ce:YAG and Tb,Ce:YAG as possible functional materials for …
Critical States Embedded In The Continuum, Milan Koirala, Alexey Yamilov, A. Basiri, Yaron Bromberg, Hui Cao, Tsampikos Kottos
Critical States Embedded In The Continuum, Milan Koirala, Alexey Yamilov, A. Basiri, Yaron Bromberg, Hui Cao, Tsampikos Kottos
Physics Faculty Research & Creative Works
We introduce a class of critical states which are embedded in the continuum (CSC) of a one-dimensional optical waveguide array with one non-Hermitian defect. These states are on the verge of being fractal and have real propagation constants. They emerge at a phase transition which is driven by the imaginary refractive index of the defective waveguide and it is accompanied by a mode segregation which reveals analogies with the Dicke super-radiance. Below this point the states are extended while above it they evolve to exponentially localized modes. An addition of a background gain or loss can turn these localized states …
One-Loop Dominance In The Imaginary Part Of The Polarizability: Application To Blackbody And Noncontact Van Der Waals Friction, Ulrich D. Jentschura, Grzegorz Lach, Maarten Dekieviet, Krzysztof Pachucki
One-Loop Dominance In The Imaginary Part Of The Polarizability: Application To Blackbody And Noncontact Van Der Waals Friction, Ulrich D. Jentschura, Grzegorz Lach, Maarten Dekieviet, Krzysztof Pachucki
Physics Faculty Research & Creative Works
Phenomenologically important quantum dissipative processes include blackbody friction (an atom absorbs counterpropagating blueshifted photons and spontaneously emits them in all directions, losing kinetic energy) and noncontact van der Waals friction (in the vicinity of a dielectric surface, the mirror charges of the constituent particles inside the surface experience drag, slowing the atom). The theoretical predictions for these processes are modified upon a rigorous quantum electrodynamic treatment, which shows that the one-loop "correction" yields the dominant contribution to the off-resonant, gauge-invariant, imaginary part of the atom's polarizability at room temperature, for typical atom-surface interactions. The tree-level contribution to the polarizability dominates …
Long-Range Atom-Wall Interactions And Mixing Terms: Metastable Hydrogen, Ulrich D. Jentschura
Long-Range Atom-Wall Interactions And Mixing Terms: Metastable Hydrogen, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
We investigate the interaction of metastable 2S hydrogen atoms with a perfectly conducting wall, including parity-breaking S-P mixing terms (with full account of retardation). The neighboring 2P1/2 and 2P3/2 levels are found to have a profound effect on the transition from the short-range, nonrelativistic regime, to the retarded form of the Casimir-Polder interaction. The corresponding P state admixtures to the metastable 2S state are calculated. We find the long-range asymptotics of the retarded Casimir-Polder potentials and mixing amplitudes for general excited states, including a fully quantum electrodynamic treatment of the dipole-quadrupole mixing term. The decay width of the …
The Role Of Multiple Electron Capture In The X-Ray Emission Process Following Charge Exchange Collisions With Neutral Targets, Sebastian Otranto, N. D. Cariatore, Ronald E. Olson
The Role Of Multiple Electron Capture In The X-Ray Emission Process Following Charge Exchange Collisions With Neutral Targets, Sebastian Otranto, N. D. Cariatore, Ronald E. Olson
Physics Faculty Research & Creative Works
In this work we theoretically study photonic spectra that follow charge exchange processes between highly charged ions and neutral argon and CO targets. The range of collision energies studied is 5 eV/amu-10 keV/amu, covering typical EBIT-traps and Solar Wind energies. Our studies are based on multiple electrons schemes within the classical trajectory Monte Carlo method. Electrons are sorted with the sequential binding energies for the target under consideration. The role played by the multiple electron capture process for the different collision systems under consideration is explicitly analyzed and its contribution separated as arising from double radiative decay and autoionizing multiple …
Composition-Dependent Structural And Transport Properties Of Amorphous Transparent Conducting Oxides, Rabi Khanal, D. Bruce Buchholz, Robert P. Chang, Julia E. Medvedeva
Composition-Dependent Structural And Transport Properties Of Amorphous Transparent Conducting Oxides, Rabi Khanal, D. Bruce Buchholz, Robert P. Chang, Julia E. Medvedeva
Physics Faculty Research & Creative Works
Structural properties of amorphous In-based oxides, In-X-O with X=Zn, Ga, Sn, or Ge, are investigated using ab initio molecular dynamics liquid-quench simulations. The results reveal that indium retains its average coordination of 5.0 upon 20% X fractional substitution for In, whereas X cations satisfy their natural coordination with oxygen atoms. This finding suggests that the carrier generation is primarily governed by In atoms, in accord with the observed carrier concentration in amorphous In-O and In-X-O. At the same time, the presence of X affects the number of six-coordinated In atoms as well as the oxygen sharing between the InO6 …
Electron- And Photon-Impact Ionization Of Furfural, D. B. Jones, E. Ali, K. L. Nixon, P. Limão-Vieira, M.-J. Hubin-Franskin, J. Delwiche, C. G. Ning, J. Colgan, Andrew J. Murray, Don H. Madison, M .J. Brunger
Electron- And Photon-Impact Ionization Of Furfural, D. B. Jones, E. Ali, K. L. Nixon, P. Limão-Vieira, M.-J. Hubin-Franskin, J. Delwiche, C. G. Ning, J. Colgan, Andrew J. Murray, Don H. Madison, M .J. Brunger
Physics Faculty Research & Creative Works
The He(i) photoelectron spectrum of furfural has been investigated, with its vibrational structure assigned for the first time. The ground and excited ionized states are assigned through ab initio calculations performed at the outer-valence Green's function level. Triple differential cross sections (TDCSs) for electron-impact ionization of the unresolved combination of the 4a" + 21a' highest and next-highest occupied molecular orbitals have also been obtained. Experimental TDCSs are recorded in a combination of asymmetric coplanar and doubly symmetric coplanar kinematics. The experimental TDCSs are compared to theoretical calculations, obtained within a molecular 3-body distorted wave framework that employed either an orientation …