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Articles 1 - 30 of 89
Full-Text Articles in Physics
Ionization Cross Sections Of Hydrogen Molecule By Electron And Positron Impact, Károly Tőkési, Robert D. Dubois
Ionization Cross Sections Of Hydrogen Molecule By Electron And Positron Impact, Károly Tőkési, Robert D. Dubois
Physics Faculty Research & Creative Works
We Present Ionization Cross Sections of Hydrogen Molecules by Electron and Positron Impact for Impact Energies between 20 and 1000 EV. a Three-Body Classical Trajectory Monte Carlo Approximation is Applied to Mimic the Collision System. in This Approach, the H2 Molecule is Modeled by a Hydrogen-Type Atom with One Active Electron Bound to a Central Core of Effective Charge with an Effective Binding Energy. Although This Model is Crude for Describing a Hydrogen Molecule, We Found that the Total Cross Sections for Positron Impact Agree Reasonably Well with the Experimental Data. for the Electron Impact, Our Calculated Cross Sections Are …
Energy And Angular Distributions In 250 Ev Electron And Positron Collisions With Argon Atom, K. Tőkési, Robert D. Dubois
Energy And Angular Distributions In 250 Ev Electron And Positron Collisions With Argon Atom, K. Tőkési, Robert D. Dubois
Physics Faculty Research & Creative Works
We present energy and angular differential cross sections for single ionization in collisions between electrons and positrons with argon atoms at 250 eV. We treat the collision classically using the three-body approximation where the target atoms are described within the single active electron approximation using a Garvey model potential and only the outermost electron is involved in the collision dynamics. Our present classical trajectory Monte Carlo model is shown to describe the ionization cross sections reasonably well and agree with existing experimental data. We show that the energy distributions, both for electron and positron impact, have the same shape and …
Electron Scattering From 1-Methyl-5-Nitroimidazole: Cross-Sections Formodeling Electron Transport Through Potential Radiosensitizers, Ana I. Lozano, Lidia Álvarez, Adrián García-Abenza, Carlos Guerra, Fábris Kossoski, Jaime Rosado, Francisco Blanco, Juan Carlos Oller, Mahmudul Hasan, Martin Centurion, Thorsten Weber, Daniel S. Slaughter, Deepthy M. Mootheril, Alexander Dorn, Sarvesh Sarvesh, Paulo Limão-Vieira, Rafael Colmenares, Gustavo García
Electron Scattering From 1-Methyl-5-Nitroimidazole: Cross-Sections Formodeling Electron Transport Through Potential Radiosensitizers, Ana I. Lozano, Lidia Álvarez, Adrián García-Abenza, Carlos Guerra, Fábris Kossoski, Jaime Rosado, Francisco Blanco, Juan Carlos Oller, Mahmudul Hasan, Martin Centurion, Thorsten Weber, Daniel S. Slaughter, Deepthy M. Mootheril, Alexander Dorn, Sarvesh Sarvesh, Paulo Limão-Vieira, Rafael Colmenares, Gustavo García
Department of Physics and Astronomy: Faculty Publications
In this study, we present a complete set of electron scattering cross-sections from 1-Methyl-5- Nitroimidazole (1M5NI) molecules for impact energies ranging from 0.1 to 1000 eV. This information is relevant to evaluate the potential role of 1M5NI as a molecular radiosensitizers. The total electron scattering cross-sections (TCS) that we previously measured with a magnetically confined electron transmission apparatus were considered as the reference values for the present analysis. Elastic scattering cross-sections were calculated by means of two different schemes: The Schwinger multichannel (SMC) method for the lower energies (below 15 eV) and the independent atom model-based screening-corrected additivity rule with …
Constraints On The Onset Of Color Transparency From Quasielastic ¹²C(E, E′P) Up To Q² = (14.2 Gev /C)², D. Bhetuwal, J. Matter, H. Szumila-Vance, C. Ayerbe Gayoso, M. L. Kabir, D. Dutta, R. Ent, D. Abrams, Z. Ahmed, B. Aljawrneh, S. Alsalmi, R. Ambrose, D. Androic, W. Armstrong, A. Asaturyan, K. Assumin-Gyimah, A. Bandari, S. Basnet, V. Berdnikov, J. Zhang, Et Al., Hall C. Collaboration
Constraints On The Onset Of Color Transparency From Quasielastic ¹²C(E, E′P) Up To Q² = (14.2 Gev /C)², D. Bhetuwal, J. Matter, H. Szumila-Vance, C. Ayerbe Gayoso, M. L. Kabir, D. Dutta, R. Ent, D. Abrams, Z. Ahmed, B. Aljawrneh, S. Alsalmi, R. Ambrose, D. Androic, W. Armstrong, A. Asaturyan, K. Assumin-Gyimah, A. Bandari, S. Basnet, V. Berdnikov, J. Zhang, Et Al., Hall C. Collaboration
Physics Faculty Publications
Quasielastic scattering on 12C(e,e′p) was measured in Hall C at Jefferson Lab for spacelike four-momentum transfer squared Q2 in the range of 8–14.2(GeV/c)2 with proton momenta up to 8.3GeV/c. The experiment was carried out in the upgraded Hall C at Jefferson Lab. It used the existing high-momentum spectrometer and the new super-high-momentum spectrometer to detect the scattered electrons and protons in coincidence. The nuclear transparency was extracted as the ratio of the measured yield to the yield calculated in the plane wave impulse approximation. Additionally, the transparency of the 1s1/2 and 1p3/2 shell …
Dissociative Excitation, Ionization, And Fragmentation Processes For Nitrogen, Oxygen, Methane, And Water Molecules By Electron Bombardment, M. Gochitashvili, R. Lomsazde, D. Kuparashvili, O. Taboridze, Roman Ya. Kezerashvili
Dissociative Excitation, Ionization, And Fragmentation Processes For Nitrogen, Oxygen, Methane, And Water Molecules By Electron Bombardment, M. Gochitashvili, R. Lomsazde, D. Kuparashvili, O. Taboridze, Roman Ya. Kezerashvili
Publications and Research
Electron–impact ionization and fragmentation of molecules are investigated by the chromatography mass-spectrometry device. While the excitation processes are investigated by an optical spectroscopy method. The spectral analysis is performed in the vacuum ultraviolet 50-130 nm spectral regions. The absolute value of the fragmentation cross-section in the dissociative ionization and excitation processes is determined. Measurements are performed in the electron energy range 25-120eV for ionization and 200-500eV for excitation processes respectively.
Design, Construction And Operation Of The Protodune-Sp Liquid Argon Tpc, The Dune Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, D. Adams, M. Adinolfi, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monsalve, M. Alrashed, C. Alt, A. Alton, Roberto Petti, Et. Al.
Design, Construction And Operation Of The Protodune-Sp Liquid Argon Tpc, The Dune Collaboration, A. Abed Abud, B. Abi, R. Acciarri, M. A. Acero, M. R. Adames, G. Adamov, D. Adams, M. Adinolfi, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, J. Ahmed, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monsalve, M. Alrashed, C. Alt, A. Alton, Roberto Petti, Et. Al.
Faculty Publications
The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber (LArTPC) that was constructed and operated in the CERN North Area at the end of the H4 beamline. This detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment (DUNE), which will be constructed at the Sandford Underground Research Facility (SURF) in Lead, South Dakota, U.S.A. The ProtoDUNE-SP detector incorporates full-size components as designed for DUNE and has an active volume of 7 × 6 × 7.2 m3. The H4 beam delivers incident particles with well-measured momenta and high-purity particle identification. …
Triply Differential Positron And Electron Impact Ionization Of Argon: Systematic Features And Scaling, Robert D. Dubois, O. G. De Lucio
Triply Differential Positron And Electron Impact Ionization Of Argon: Systematic Features And Scaling, Robert D. Dubois, O. G. De Lucio
Physics Faculty Research & Creative Works
Triply differential data are presented for the 200 eV positron and electron impact ionization of argon. Six electron emission energies between 2.6 and 19 eV, and for scattering angles of 2, 3, and 4 degrees cover a momentum transfer range of 0.16 to 0.31 a.u. The binary and recoil intensities are fitted using a double peak structure in both regions, which, for the present kinematic conditions, are unresolved. The fitted peak intensities and angular positions are shown to have systematic dependences as a function of the momentum transfer and kinematic emission angle, respectively, and illustrate projectile charge effects. A comparison …
Few Body Effects In The Electron And Positron Impact Ionization Of Atoms, R. I. Campeanu, Colm T. Whelan
Few Body Effects In The Electron And Positron Impact Ionization Of Atoms, R. I. Campeanu, Colm T. Whelan
Physics Faculty Publications
Triple differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of energy sharing geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions that cannot be separately detected in an experiment with a single projectile. Results will be presented in kinematics where the electron impact ionization appears to be well understood and using the same kinematics positron cross sections will …
First Results On Protodune-Sp Liquid Argon Time Projection Chamber Performance From A Beam Test At The Cern Neutrino Platform, B. Abi, A. Abed Abud, R. Acciarri, M. A. Acero, G. Adamowski, D. Adams, P. Adrien, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, M. Antonova, Roberto Petti, Et. Al.
First Results On Protodune-Sp Liquid Argon Time Projection Chamber Performance From A Beam Test At The Cern Neutrino Platform, B. Abi, A. Abed Abud, R. Acciarri, M. A. Acero, G. Adamowski, D. Adams, P. Adrien, M. Adinolfi, Z. Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andrianala, S. Andringa, A. Ankowski, M. Antonova, Roberto Petti, Et. Al.
Faculty Publications
The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of 7.2 × 6.1 × 7.0 m3 . It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV/𝑐 to 7 GeV/𝑐. Beam line instrumentation provides accurate momentum measurements and particle identification. The ProtoDUNE-SP detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment, and it incorporates full-size components as designed for that module. This paper describes the beam line, the …
Collision Of Li2+ With Li(2s) And Li(2p): Differential And Total Ionization; Discrete Excitations; Elastic Scattering, And Total Cross Section, H.R.J. Walters, Colm T. Whelan
Collision Of Li2+ With Li(2s) And Li(2p): Differential And Total Ionization; Discrete Excitations; Elastic Scattering, And Total Cross Section, H.R.J. Walters, Colm T. Whelan
Physics Faculty Publications
The coupled pseudostate approximation (McGovern et al 2009 Phys. Rev. A 79 042707) has been applied to Li2+ + Li(2s, 2p0,±1) collisions at 16 MeV with emphasis on studying the fully differential ionization measurements of Ghanbari-Adivi et al in the azimuthal plane (2017 J. Phys. B: At. Mol. Opt. Phys. 50 215202). The states of the valence electron in the Li target are calculated using the model potential of Stein (1993 J. Phys. B: At. Mol. Opt. Phys. 26 2087). Altogether 164 states with angular momenta l = 0 to 9 are employed in …
(E,2e) Ionization Studies Of N₂ At Low To Intermediate Energies From A Coplanar Geometry To The Perpendicular Plane, Ahmad Sakaamini, Matthew Harvey, Sadek Amami, Andrew James Murray, Don H. Madison, Chuangang Ning
(E,2e) Ionization Studies Of N₂ At Low To Intermediate Energies From A Coplanar Geometry To The Perpendicular Plane, Ahmad Sakaamini, Matthew Harvey, Sadek Amami, Andrew James Murray, Don H. Madison, Chuangang Ning
Physics Faculty Research & Creative Works
Synopsis. The progress of experimental and theoretical measurements for (e,2e) ionization cross sections from Nitrogen molecules is presented. Results are given for energies from ~10 eV above the ionization potential (IP) through to ~100 eV above the IP for the 3σg, 1πu and 2σg states.
Electron-Impact Ionization Of H₂O At Low Projectile Energy: Internormalized Triple-Differential Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Khokon Hossen, Esam Ali, Chuangang Ning, James Colgan, Don H. Madison, Andrew Dorn
Electron-Impact Ionization Of H₂O At Low Projectile Energy: Internormalized Triple-Differential Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Khokon Hossen, Esam Ali, Chuangang Ning, James Colgan, Don H. Madison, Andrew Dorn
Physics Faculty Research & Creative Works
We report a combined experimental and theoretical study of the electron-impact ionization of water (H2O) at the relatively low incident energy of E0=81eV in which either the 1b1 or 3a1 orbitals are ionized leading to the stable H2O cation. The experimental data were measured by using a reaction microscope, which can cover nearly the entire 4π solid angle for the secondary electron emission over a range of ejection energies. We present experimental data for the scattering angles of 6⁰ and 10⁰ for the faster of the two outgoing electrons as a function …
Comparison Of Experimental And Theoretical Fully Differential Cross Sections For Single Ionization Of The 2s And 2p States Of Li By O⁸⁺ Ions, Ebrahim Ghanbari-Adivi, Daniel Fischer, Natalia Ferreira, Johannes Goullon, Renate Hubele, Aaron Laforge, Michael Schulz, Don H. Madison
Comparison Of Experimental And Theoretical Fully Differential Cross Sections For Single Ionization Of The 2s And 2p States Of Li By O⁸⁺ Ions, Ebrahim Ghanbari-Adivi, Daniel Fischer, Natalia Ferreira, Johannes Goullon, Renate Hubele, Aaron Laforge, Michael Schulz, Don H. Madison
Physics Faculty Research & Creative Works
This paper presents a full three-dimensional (3D) comparison between experiment and theory for 24 MeV O8+ single ionization of the 2s ground state of lithium and the 2p excited state. Two theoretical approximations are examined: the three-body continuum distorted-wave (3DW) and three-body continuum distorted-wave-eikonal initial state (3DW-EIS). Normally, there is a significant difference between these two approaches and the 3DW-EIS is in much better agreement with experiment. In this case, there is very little difference between the two approaches and both are in very good agreement with experiment. For the excited 2p state, the 3D cross sections would exhibit …
Influence Of Orbital Symmetry On Diffraction Imaging With Rescattering Electron Wave Packets, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michele Sclafani, Hugo Pires, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, Thomas Pfeifer, C. D. Lin, Jens Biegert
Influence Of Orbital Symmetry On Diffraction Imaging With Rescattering Electron Wave Packets, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michele Sclafani, Hugo Pires, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, Thomas Pfeifer, C. D. Lin, Jens Biegert
Physics Faculty Research & Creative Works
The ability to directly follow and time-resolve the rearrangement of the nuclei within molecules is a frontier of science that requires atomic spatial and few-femtosecond temporal resolutions. While laser-induced electron diffraction can meet these requirements, it was recently concluded that molecules with particular orbital symmetries (such as πg) cannot be imaged using purely backscattering electron wave packets without molecular alignment. Here, we demonstrate, in direct contradiction to these findings, that the orientation and shape of molecular orbitals presents no impediment for retrieving molecular structure with adequate sampling of the momentum transfer space. We overcome previous issues by showcasing …
Kinematically Complete Study Of Low-Energy Electron-Impact Ionization Of Argon: Internormalized Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Oleg Zatsarinny, Thomas Pflüger, Marvin Weyland, Alexander Dorn, Don H. Madison, Klaus Bartschat
Kinematically Complete Study Of Low-Energy Electron-Impact Ionization Of Argon: Internormalized Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Oleg Zatsarinny, Thomas Pflüger, Marvin Weyland, Alexander Dorn, Don H. Madison, Klaus Bartschat
Physics Faculty Research & Creative Works
As a further test of advanced theoretical methods to describe electron-impact single-ionization processes in complex atomic targets, we extended our recent work on Ne(2p) ionization [X. Ren, S. Amami, O. Zatsarinny, T. Pflüger, M. Weyland, W. Y. Baek, H. Rabus, K. Bartschat, D. Madison, and A. Dorn, Phys. Rev. A 91, 032707 (2015)PLRAAN1050-294710.1103/PhysRevA.91.032707] to Ar(3p) ionization at the relatively low incident energy of E0 = 66 eV. The experimental data were obtained with a reaction microscope, which can cover nearly the entire 4π solid angle for the secondary electron emission. We present experimental data for detection angles of 10, …
Experimental And Theoretical Triple-Differential Cross Sections For Tetrahydrofuran Ionized By Low-Energy 26-Ev-Electron Impact, Esam Ali, Xueguang Ren, Alexander Dorn, Chuangang Ning, James Colgan, Don H. Madison
Experimental And Theoretical Triple-Differential Cross Sections For Tetrahydrofuran Ionized By Low-Energy 26-Ev-Electron Impact, Esam Ali, Xueguang Ren, Alexander Dorn, Chuangang Ning, James Colgan, Don H. Madison
Physics Faculty Research & Creative Works
We report an experimental and theoretical study of low-energy electron-impact ionization of tetrahydrofuran, which is a molecule of biological interest. The experiments were performed using an advanced reaction microscope specially built for electron-impact ionization studies. The theoretical calculations were performed within the molecular three-body distorted-wave model. Reasonably good agreement is found between experiment and theory.
Comparison Of Experimental And Theoretical Triple Differential Cross Sections For The Single Ionization Of Co₂ (1Πg) By Electron Impact, Zehra N. Ozer, Esam Ali, Mevlut Dogan, Murat Yavuz, Osman Alwan, Adnan Naja, Ochbadrakh Chuluunbaatar, Boghos B. Joulakian, Chuan-Gang Ning, James Colgan, Don H. Madison
Comparison Of Experimental And Theoretical Triple Differential Cross Sections For The Single Ionization Of Co₂ (1Πg) By Electron Impact, Zehra N. Ozer, Esam Ali, Mevlut Dogan, Murat Yavuz, Osman Alwan, Adnan Naja, Ochbadrakh Chuluunbaatar, Boghos B. Joulakian, Chuan-Gang Ning, James Colgan, Don H. Madison
Physics Faculty Research & Creative Works
Experimental and theoretical triple differential cross sections for intermediate-energy (250 eV) electron-impact single ionization of the CO2 are presented for three fixed projectile scattering angles. Results are presented for ionization of the outermost 1πg molecular orbital of CO2 in a coplanar asymmetric geometry. The experimental data are compared to predictions from the three-center Coulomb continuum approximation for triatomic targets, and the molecular three-body distorted wave (M3DW) model. It is observed that while both theories are in reasonable qualitative agreement with experiment, the M3DW is in the best overall agreement with experiment.
Analytical Model For Calibrating Laser Intensity In Strong-Field-Ionization Experiments, Song-Feng. Zhao, Anh-Thu Le, Cheng Jin, Xu Wang, C. D. Lin
Analytical Model For Calibrating Laser Intensity In Strong-Field-Ionization Experiments, Song-Feng. Zhao, Anh-Thu Le, Cheng Jin, Xu Wang, C. D. Lin
Physics Faculty Research & Creative Works
The interaction of an intense laser pulse with atoms and molecules depends extremely nonlinearly on the laser intensity. Yet experimentally there still exists no simple reliable methods for determining the peak laser intensity within the focused volume. Here we present a simple method, based on an improved Perelomov-Popov-Terent'ev model, that would allow the calibration of laser intensities from the measured ionization signals of atoms or molecules. The model is first examined by comparing ionization probabilities (or signals) of atoms and several simple diatomic molecules with those from solving the time-dependent Schrödinger equation. We then show the possibility of using this …
Calculation Of Nonlinear Optical Damage From Space-Time-Tailored Pulses In Dielectrics, Thomas E. Lanier, Jeremy R. Gulley
Calculation Of Nonlinear Optical Damage From Space-Time-Tailored Pulses In Dielectrics, Thomas E. Lanier, Jeremy R. Gulley
Faculty and Research Publications
Control of the time duration of a laser pulse as it focuses spatially in a material provides a means for delaying the onset of nonlinear e↵ects during propagation. We investigate simultaneous space-time focusing (SSTF) of femtosecond radially-chirped annular pulses in Kerr dielectrics. The energy and temporal chirp of pulses incident upon a grating-grating-lens system are varied in simulations that solve the unidirectional pulse propagation equation. This system is modeled by inserting transformations that act on the electric field obtained from propagation from one component to the next. The propagation is coupled to the time evolution of the free charge density …
Quantum Interference In The Field Ionization Of Rydberg Atoms, Rachel Feynman, Jacob A. Hollingsworth, Michael Vennettilli, Tamas Budner, Ryan Zmiewski, Donald P. Fahey, Thomas J. Carroll, Michael W. Noel
Quantum Interference In The Field Ionization Of Rydberg Atoms, Rachel Feynman, Jacob A. Hollingsworth, Michael Vennettilli, Tamas Budner, Ryan Zmiewski, Donald P. Fahey, Thomas J. Carroll, Michael W. Noel
Physics and Astronomy Faculty Publications
We excite ultracold rubidium atoms in a magneto-optical trap to a coherent superposition of the three |mj | sublevels of the 37d5/2 Rydberg state. After some delay, during which the relative phases of the superposition components can evolve, we apply an electric field pulse to ionize the Rydberg electron and send it to a detector. The electron traverses many avoided crossings in the Stark levels as it ionizes. The net effect of the transitions at these crossings is to mix the amplitudes of the initial superposition into the same final states at ionization. Similar to a Mach-Zehnder interferometer, the three …
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
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 …
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
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
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.
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
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 …
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
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).
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
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.
Interference Effects For Intermediate Energy Electron-Impact Ionization Of H₂ And N₂ Molecules, Zehra Nur Ozer, Hari Chaluvadi, Don H. Madison, Mevlut Dogan
Interference Effects For Intermediate Energy Electron-Impact Ionization Of H₂ And N₂ Molecules, Zehra Nur Ozer, Hari Chaluvadi, Don H. Madison, Mevlut Dogan
Physics Faculty Research & Creative Works
We have studied electron impact ionization of H2 and N2 molecules at intermediate energies to look for possible two center interference effects experimentally and theoretically. Here we report a study of the interference factor I for 250 eV electron-impact ionization. The experimental measurements are performed using a crossed-beam-type electron-electron coincidence spectrometer and theoretical calculations are obtained using the Molecular Three Body Distorted Wave Approximation (M3DW). We found that the I-factor demonstrated strong evidence for two-center interference effects for both H2 and N2. We also found that the I-factor is more sensitive to projectile angular scans …
Imaging The Dipole-Dipole Energy Exchange Between Ultracold Rubidium Rydberg Atoms, Donald P. Fahey, Thomas J. Carroll, Michael W. Noel
Imaging The Dipole-Dipole Energy Exchange Between Ultracold Rubidium Rydberg Atoms, Donald P. Fahey, Thomas J. Carroll, Michael W. Noel
Physics and Astronomy Faculty Publications
The long-range, anisotropic nature of the interaction among atoms in an ultracold dipolar gas leads to a rich array of possibilities for studying many-body physics. In this work, an ultracold gas of highly excited atoms is used to study energy transport due to the long-range dipole-dipole interaction. A technique is developed to measure both the internal energy states of the interacting Rydberg atoms and their positions in space. This technique is demonstrated by observing energy exchange between two spatially separated groups of Rydberg atoms excited to two different internal states. Simulations confirm the general features of the energy transport in …
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 …
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), …