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Articles 1  30 of 48
FullText Articles in Physics
Semiclassically Modeling Hydrogen At Rydberg States Immersed In Electromagnetic Fields, Jaron Williams
Semiclassically Modeling Hydrogen At Rydberg States Immersed In Electromagnetic Fields, Jaron Williams
Mathematics Senior Capstone Papers
Originally, closedorbit theory was developed in order to analyze oscillations in the near ionization threshold (Rydberg) densities of states for atoms in strong external electric and magnetic fields. Oscillations in the density of states were ascribed to classical orbits that began and ended near the atom. In essence, observed outgoing waves following the classical path return and interfere with original outgoing waves, giving rise to oscillations. Elastic scattering from one closed orbit to another gives additional oscillations in the crosssection. This study examines how quantum theory can be properly used in combination with classical orbit theory in order to study ...
Continuity Of Heavy Rydberg Behaviour In The Ungerade IonPair States Of H2, Alexander M. Chartrand, Robert J. Donovan, Kenneth P. Lawley, Elizabeth Mccormack
Continuity Of Heavy Rydberg Behaviour In The Ungerade IonPair States Of H2, Alexander M. Chartrand, Robert J. Donovan, Kenneth P. Lawley, Elizabeth Mccormack
Physics Faculty Research and Scholarship
Heavy Rydberg behaviour and absolute quantum defects are reported for resonances in the ungerade manifold of H_{2} above the (1s, 3l) dissociation limit. The continuity of the vibrational progression of the B''Bbar state through the crossing with the 3p asymptote is demonstrated and a predominantly diabatic picture of the vibrational motion emerges, indicating that the ionpair resonances possess little 6^{1}Σ_{u}^{+} state character.
LongRange Interactions Of Hydrogen Atoms In Excited States. I. 2s1s Interactions And DiracΔ Perturbations, Chandra Mani Adhikari, Vincent Debierre, Arthur N. Matveev, Nikolai N. Kolachevsky, Ulrich D. Jentschura
LongRange Interactions Of Hydrogen Atoms In Excited States. I. 2s1s Interactions And DiracΔ Perturbations, Chandra Mani Adhikari, Vincent Debierre, Arthur N. Matveev, Nikolai N. Kolachevsky, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The theory of the longrange interaction of metastable excited atomic states with groundstate atoms is analyzed. We show that the longrange interaction is essentially modified when quasidegenerate states are available for virtual transitions. A discrepancy in the literature regarding the van der Waals coefficient C_{6} (2S ;1 S ) describing the interaction of metastable atomic hydrogen ( 2 S state) with a groundstate hydrogen atom is resolved. In the the van der Waals range a_{0} ≪ R ≪ a_{0} / α , where a_{0} = ℏ / α m c is the Bohr radius and α is the finestructure constant, one finds the symmetrydependent result ...
Photon Beam Asymmetry Σ For Η And Η′ Photoproduction From The Proton, P. Collins, B. G. Ritchie, M. Dugger, A. V. Anisovich, M. Doring, E. Klempt, V. A. Nikonov, D. Rönchen, D. Sadasivan, A. Sarantsev, M. J. Amaryan, A. Klein
Photon Beam Asymmetry Σ For Η And Η′ Photoproduction From The Proton, P. Collins, B. G. Ritchie, M. Dugger, A. V. Anisovich, M. Doring, E. Klempt, V. A. Nikonov, D. Rönchen, D. Sadasivan, A. Sarantsev, M. J. Amaryan, A. Klein
Physics Faculty Publications
Measurements of the linearlypolarized photon beam asymmetry Σ for photoproduction from the proton of η and η ′ mesons are reported. A linearlypolarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γ p → η p reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γ p → η ′ p reaction. For γ p → η p , the data reported here considerably extend the range of measurements to higher energies, and are consistent with ...
Observations Of The High Vibrational Levels Of The B′′B̄ 1Σu+ State Of H2, Alexander M. Chartrand, W. Duan, R. C. Ekey, Elizabeth Mccormack
Observations Of The High Vibrational Levels Of The B′′B̄ 1Σu+ State Of H2, Alexander M. Chartrand, W. Duan, R. C. Ekey, Elizabeth Mccormack
Physics Faculty Research and Scholarship
Doubleresonance laser spectroscopy via the E F ^{1}Σ_{g}^{+}, v'=6, J'=02 state was used to probe the high vibrational levels of the B"Bbar ^{1}Σ_{u}^{+} state of molecular hydrogen. Resonantlyenhanced multiphoton ionization spectra were recorded by detecting ion production as a function of energy using a time of flight mass spectrometer. New measurements of energies for the v=5166 levels for the B"Bbar state of H_{2} are reported, which, taken with previous results, span the v=4669 vibrational levels. Results for energy levels are compared to theoretical closecoupled calculations [L. Wolniewicz, T. Orlikowski ...
Muonic Bound Systems, Virtual Particles, And Proton Radius, Ulrich D. Jentschura
Muonic Bound Systems, Virtual Particles, And Proton Radius, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The proton radius puzzle questions the selfconsistency of theory and experiment in light muonic and electronic bound systems. Here we summarize the current status of virtual particle models as well as Lorentzviolating models that have been proposed in order to explain the discrepancy. Highly charged oneelectron ions and muonic bound systems have been used as probes of the strongest electromagnetic fields achievable in the laboratory. The average electric field seen by a muon orbiting a proton is comparable to hydrogenlike uranium and, notably, larger than the electric field in the most advanced stronglaser facilities. Effective interactions due to virtual annihilation ...
Measurement Of The Formation Rate Of Muonic Hydrogen Molecules, V. A. Andreev, T. I. Banks, R. M. Carey, T. A. Case, S. M. Clayton, K. M. Crowe, J. Deutsch, J. Egger, S. J. Freedman, V. A. Ganzha, Tim Gorringe, F. E. Gray, D. W. Hertzog, M. Hildebrandt, P. Kammel, B. Kiburg, S. Knaack, P. A. Kravtsov, A. G. Krivshich, B. Lauss, K. R. Lynch, E. M. Maev, O. E. Maev, F. Mulhauser, C. Petitjean, G. E. Petrov, R. Prieels, G. N. Schapkin, G. G. Semenchuk, M. A. Soroka, Vladimir Tishchenko, A. A. Vasilyev, A. A. Vorobyov, M. E. Vznuzdaev, P. Winter
Measurement Of The Formation Rate Of Muonic Hydrogen Molecules, V. A. Andreev, T. I. Banks, R. M. Carey, T. A. Case, S. M. Clayton, K. M. Crowe, J. Deutsch, J. Egger, S. J. Freedman, V. A. Ganzha, Tim Gorringe, F. E. Gray, D. W. Hertzog, M. Hildebrandt, P. Kammel, B. Kiburg, S. Knaack, P. A. Kravtsov, A. G. Krivshich, B. Lauss, K. R. Lynch, E. M. Maev, O. E. Maev, F. Mulhauser, C. Petitjean, G. E. Petrov, R. Prieels, G. N. Schapkin, G. G. Semenchuk, M. A. Soroka, Vladimir Tishchenko, A. A. Vasilyev, A. A. Vorobyov, M. E. Vznuzdaev, P. Winter
Physics and Astronomy Faculty Publications
Background: The rate λ_{ppμ} characterizes the formation of ppμ molecules in collisions of muonic pμ atoms with hydrogen. In measurements of the basic weak muon capture reaction on the proton to determine the pseudoscalar coupling g_{P}, capture occurs from both atomic and molecular states. Thus knowledge of λ_{ppμ} is required for a correct interpretation of these experiments.
Purpose: Recently the MuCap experiment has measured the capture rate Λ_{S} from the singlet pμ atom, employing a lowdensity active target to suppress ppμ formation [V. Andreev et al. (MuCap Collaboration), Phys. Rev. Lett. 110, 012504 (2013)]. Nevertheless, given ...
LongRange AtomWall Interactions And Mixing Terms: Metastable Hydrogen, Ulrich D. Jentschura
LongRange AtomWall 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 paritybreaking SP mixing terms (with full account of retardation). The neighboring 2P_{1/2} and 2P_{3/2} levels are found to have a profound effect on the transition from the shortrange, nonrelativistic regime, to the retarded form of the CasimirPolder interaction. The corresponding P state admixtures to the metastable 2S state are calculated. We find the longrange asymptotics of the retarded CasimirPolder potentials and mixing amplitudes for general excited states, including a fully quantum electrodynamic treatment of the dipolequadrupole mixing term. The decay width ...
Data Analysis Techniques, Differential Cross Sections, And Spin Density Matrix Elements For The Reaction ᵞP → Φp, K.P. Adhikari, D. Adikaram, M.J. Amaryan, A. Klein, S. Koirala, Clas Collaboration
Data Analysis Techniques, Differential Cross Sections, And Spin Density Matrix Elements For The Reaction ᵞP → Φp, K.P. Adhikari, D. Adikaram, M.J. Amaryan, A. Klein, S. Koirala, Clas Collaboration
Physics Faculty Publications
Highstatistics measurements of differential cross sections and spin density matrix elements for the reaction ᵞp → ϕp have been made using the CLAS detector at Jefferson Lab. We cover centerofmass energies (√s) from 1.97 to 2.84 GeV, with an extensive coverage in the ϕ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the ϕ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged(ϕ → K^{+} K^{}) and neutral( ϕ → (K^{O}_{S}K^{O}_{L}) K ...
Low Energy (E, 2e) Study From The 1t₂ Orbital Of Ch₄, Shenyue Xu, Hari Chaluvadi, Xueguang Ren, Thomas Pfluger, Arne Senftleben, Chuangang Ning, Shuncheng Yan, Peng Zhang, Jie Yang, Xinwen Ma, Joachim Hermann Ullrich, Don H. Madison, Alexander Dorn
Low Energy (E, 2e) Study From The 1t₂ Orbital Of Ch₄, Shenyue Xu, Hari Chaluvadi, Xueguang Ren, Thomas Pfluger, Arne Senftleben, Chuangang Ning, Shuncheng Yan, Peng Zhang, Jie Yang, Xinwen Ma, Joachim Hermann Ullrich, Don H. Madison, Alexander Dorn
Physics Faculty Research & Creative Works
Single ionization of the methane (CH_{4}) 1t_{2} orbital by 54 eV electron impact has been studied experimentally and theoretically. The measured triple differential cross sections cover nearly a 4π solid angle for the emission of low energy electrons and a range of projectile scattering angles. Experimental data are compared with theoretical calculations from the distorted wave Born approximation and the molecular threebody distorted wave models. It is found that theory can give a proper description of the main features of experimental cross section only at smaller scattering angles. For larger scattering angles, significant discrepancies between experiment and theory ...
Relativistic ReducedMass And Recoil Corrections To Vacuum Polarization In Muonic Hydrogen, Muonic Deuterium, And Muonic Helium Ions, Ulrich D. Jentschura
Relativistic ReducedMass And Recoil Corrections To Vacuum Polarization In Muonic Hydrogen, Muonic Deuterium, And Muonic Helium Ions, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The reducedmass dependence of relativistic and radiative effects in simple muonic bound systems is investigated. The spindependent nuclear recoil correction of order (Zα)^{4}μ^{3}/m^{2}_{N} is evaluated for muonic hydrogen and deuterium and muonic helium ions (μ is the reduced mass and m_{N} is the nuclear mass). Relativistic corrections to vacuum polarization of order α(Zα)^{4}μ are calculated, with a full account of the reducedmass dependence. The results shift theoretical predictions. The radiativerecoil correction to vacuum polarization of order α(Zα)^{5}ln^{2}(Zα) μ^{2}/m_{N} is obtained in leading ...
HydrogenDeuterium Isotope Shift: From The 1s2sTransition Frequency To The ProtonDeuteron ChargeRadius Difference, Ulrich D. Jentschura, Arthur N. Matveev, Christian G. Parthey, Janis Alnis, Randolf Pohl, Th H. Udem, Nikolai N. Kolachevsky, Theodor Wolfgang Hansch
HydrogenDeuterium Isotope Shift: From The 1s2sTransition Frequency To The ProtonDeuteron ChargeRadius Difference, Ulrich D. Jentschura, Arthur N. Matveev, Christian G. Parthey, Janis Alnis, Randolf Pohl, Th H. Udem, Nikolai N. Kolachevsky, Theodor Wolfgang Hansch
Physics Faculty Research & Creative Works
We analyze and review the theory of the hydrogendeuterium isotope shift for the 1S2S transition, which is one of the most accurately measured isotope shifts in any atomic system, in view of a recently improved experiment. A tabulation of all physical effects that contribute to the isotope shift is given. These include the Dirac binding energy, quantum electrodynamic effects, including recoil corrections, and the nuclearsize effect, including the pertaining relativistic and radiative corrections. From a comparison of the theoretical result Δf_{th}=670999566.90(66)(60)kHz (exclusive of the nonrelativistic nuclearfinitesize correction) and the experimental result Δf_{expt}=670994334605 ...
ThreeBody Dynamics In Single Ionization Of Atomic Hydrogen By 75 Kev Proton Impact, Ahmad Hasan, Michael Schulz, Aaron C. Laforge, Jason S. Alexander, M. F. Ciappina, M. A. Khakoo, Kisra Nayomal Egodapitiya
ThreeBody Dynamics In Single Ionization Of Atomic Hydrogen By 75 Kev Proton Impact, Ahmad Hasan, Michael Schulz, Aaron C. Laforge, Jason S. Alexander, M. F. Ciappina, M. A. Khakoo, Kisra Nayomal Egodapitiya
Physics Faculty Research & Creative Works
Doubly differential cross sections for single ionization of atomic hydrogen by 75 keV proton impact have been measured and calculated as a function of the projectile scattering angle and energy loss. This pure threebody collision system represents a fundamental test case for the study of the reaction dynamics in fewbody systems. A comparison between theory and experiment reveals that threebody dynamics is important at all scattering angles and that an accurate description of the role of the projectiletargetnucleus interaction remains a major challenge to theory.
Reexamining Blackbody Shifts For Hydrogenlike Ions, Ulrich D. Jentschura, Martin K. Haas
Reexamining Blackbody Shifts For Hydrogenlike Ions, Ulrich D. Jentschura, Martin K. Haas
Physics Faculty Research & Creative Works
We investigate blackbodyinduced energy shifts for lowlying levels of atomic systems, with a special emphasis on transitions used in current and planned highprecision experiments on atomic hydrogen and ionized helium. Finestructure and Lambshiftinduced blackbody shifts are found to increase with the square of the nuclear charge number, whereas blackbody shifts due to virtual transitions decrease with increasing nuclear charge as the fourth power of the nuclear charge. We also investigate the decay width acquired by the ground state of atomic hydrogen, due to interaction with blackbody photons. The corresponding width is due to an instability against excitation to higher excited ...
Studies Of Breakdown In A Pressurized Rf Cavity, M. Bastaninejad, A. A. Elmustafa, C. M. Ankenbrandt, A. Moretti, M. Popovic, K. Yonehara, D. M. Kaplan, M. Alsharo'a, P. M. Hanlet, R. P. Johnson, M. Kuchnir, D. Newsham, D. V. Rose, C. Thoma, D. R. Welch
Studies Of Breakdown In A Pressurized Rf Cavity, M. Bastaninejad, A. A. Elmustafa, C. M. Ankenbrandt, A. Moretti, M. Popovic, K. Yonehara, D. M. Kaplan, M. Alsharo'a, P. M. Hanlet, R. P. Johnson, M. Kuchnir, D. Newsham, D. V. Rose, C. Thoma, D. R. Welch
Mechanical & Aerospace Engineering Faculty Publications
Microscopic images of the surfaces of metallic electrodes used in highpressure gasfilled 805 MHz RF cavity experiments [1] have been used to investigate the mechanism of RF breakdown [2]. The images show evidence for melting and boiling in small regions of ∼10 micron diameter on tungsten, molybdenum, and beryllium electrode surfaces. In these experiments, the dense hydrogen gas in the cavity prevents electrons or ions from being accelerated to high enough energy to participate in the breakdown process so that the only important variables are the fields and the metallic surfaces. The distributions of breakdown remnants on the electrode surfaces ...
Measurement Of Ep→Epπᵒ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. HydeWright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang
Measurement Of Ep→Epπᵒ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. HydeWright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang
Physics Faculty Publications
The beam spin asymmetry (BSA) in the exclusive reaction ^{→}ep→epπ0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer (CLAS). The x_{B},Q^{2},t , and ϕ dependences of the π^{0} BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sinϕ function and their amplitudes are extracted. Overall, they are of the order of 0.04–0.11 and roughly independent of t . This is the signature of a nonzero longitudinaltransverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as ...
TwoLoop Bethe Logarithms For Non S Levels, Ulrich D. Jentschura
TwoLoop Bethe Logarithms For Non S Levels, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
Twoloop Bethe logarithms are calculated for excited P and D states in hydrogenlike systems, and estimates are presented for all states with higher angular momenta. These results complete our knowledge of the P and D energy levels in hydrogen at the order of α^{8} m_{e}c^{2}, where me is the electron mass and c is the speed of light, and scale as Z^{6}, where Z is the nuclear charge number. Our analytic and numerical calculations are consistent with the complete absence of logarithmic terms of order (απ)^{2} (Zα)^{6} ln [(Zα)^{2}] m_{e}c ...
Quantum Electrodynamic Corrections To The Hyperfine Structure Of Excited S States, Ulrich D. Jentschura, Vladimir A. Yerokhin
Quantum Electrodynamic Corrections To The Hyperfine Structure Of Excited S States, Ulrich D. Jentschura, Vladimir A. Yerokhin
Physics Faculty Research & Creative Works
Statedependent quantum electrodynamic corrections are evaluated for the hyperfine splitting of nS states for arbitrary principal quantum number n. The calculations comprise both the selfenergy and the vacuumpolarization correction of order α(Zα) 2 EF and the recoil correction of order (Zα)^{2} (m/M) E_{F}. Higherorder corrections are summarized and partly reevaluated as well. Accurate predictions for hydrogen hyperfine splitting intervals of nS states with n=2,...,8 are presented. The results obtained are important due to steady progress in hydrogen spectroscopy for transitions involving highly excited S states.
YoungType Interference In (E, 2e) Ionization Of H₂, D. S. MilneBrownlie, Matthew S. Foster, Junfang Gao, B. Lohmann, Don H. Madison
YoungType Interference In (E, 2e) Ionization Of H₂, D. S. MilneBrownlie, Matthew S. Foster, Junfang Gao, B. Lohmann, Don H. Madison
Physics Faculty Research & Creative Works
We have investigated the electron impact single ionization of the hydrogen molecule, with fully determined kinematics. The experimental and theoretical results are compared with He ionization under the same conditions. The results indicate that the ejected electron angular distribution for H_{2} is modified due to Youngtype interference between ionization amplitudes for scattering from the two centers in the hydrogen molecule. The observable result is a suppression of the backward scattering (recoil) peak compared with the binary peak.
Photoionization Broadening Of The 1s2s Transition In A Beam Of Atomic Hydrogen, Nikolai N. Kolachevsky, Martin K. Haas, Ulrich D. Jentschura, Maximilian Herrmann, Peter Fendel, Marc P. Fischer, Ronald Holzwarth, Th H. Udem, Christoph H. Keitel, Theodor Wolfgang Hansch
Photoionization Broadening Of The 1s2s Transition In A Beam Of Atomic Hydrogen, Nikolai N. Kolachevsky, Martin K. Haas, Ulrich D. Jentschura, Maximilian Herrmann, Peter Fendel, Marc P. Fischer, Ronald Holzwarth, Th H. Udem, Christoph H. Keitel, Theodor Wolfgang Hansch
Physics Faculty Research & Creative Works
We consider the excitation dynamics of the twophoton 1S  2S transition in a beam of atomic hydrogen by 243 nm laser radiation. Specifically, we study the impact of ionization damping on the transition line shape, caused by the possibility of ionization of the 2S level by the same laser field. Using a Monte Carlo simulation, we calculate the line shape of the 1S  2S transition for the experimental geometry used in the two latest absolute frequency measurements [M. Niering, Phys. Rev. Lett. 84, 5496 (2000) and M. Fischer, Phys. Rev. Lett. 92, 230802 (2004)]. The calculated line shift and linewidth ...
Theoretical Treatment Of ElectronImpact Ionization Of Molecules, Junfang Gao, Jerry Peacher, Don H. Madison
Theoretical Treatment Of ElectronImpact Ionization Of Molecules, Junfang Gao, Jerry Peacher, Don H. Madison
Physics Faculty Research & Creative Works
There is currently no reliable theory for calculating the fully differential cross section (FDCS) for low energy electronimpact ionization of molecules. All of the existing experimental FDCS data represent averages over all molecular orientations and this can be an important theoretical complication for calculations that are computer intensive. We have found that using an averaged molecular orbital is an accurate approximation for ionization of ground states. In this paper, we will describe the approximation, discuss its expected range of validity and show some FDCS results using the approximation for ionization of H2 and N2
Precise Calculation Of Transition Frequencies Of Hydrogen And Deuterium Based On A LeastSquares Analysis, Ulrich D. Jentschura, Svetlana A. Kotochigova, Eric Olivier Le Bigot, Peter J. Mohr, Barry N. Taylor
Precise Calculation Of Transition Frequencies Of Hydrogen And Deuterium Based On A LeastSquares Analysis, Ulrich D. Jentschura, Svetlana A. Kotochigova, Eric Olivier Le Bigot, Peter J. Mohr, Barry N. Taylor
Physics Faculty Research & Creative Works
We combine a limited number of accurately measured transition frequencies in hydrogen and deuterium, recent quantum electrodynamics (QED) calculations, and, as an essential additional ingredient, a generalized leastsquares analysis, to obtain precise and optimal predictions for hydrogen and deuterium transition frequencies. Some of the predicted transition frequencies have relative uncertainties more than an order of magnitude smaller than that of the g factor of the electron, which was previously the most accurate prediction of QED.
Complete TwoLoop Correction To The BoundElectron Factor, Krzysztof Pachucki, Andrzej Czarnecki, Ulrich D. Jentschura, Vladimir A. Yerokhin
Complete TwoLoop Correction To The BoundElectron Factor, Krzysztof Pachucki, Andrzej Czarnecki, Ulrich D. Jentschura, Vladimir A. Yerokhin
Physics Faculty Research & Creative Works
Within a systematic approach based on dimensionally regularized nonrelativistic quantum electrodynamics, we derive a complete result for the twoloop correction to order ( α/ π )^{2} ( Zα )^{4} for the g factor of an electron bound in an nS state of a hydrogenlike ion. The results obtained significantly improve the accuracy of the theoretical predictions for the hydrogenlike carbon and oxygen ions and influence the value of the electron mass inferred from gfactor measurements. D
Calculation Of Hydrogenic Bethe Logarithms For Rydberg States, Ulrich D. Jentschura, Peter J. Mohr
Calculation Of Hydrogenic Bethe Logarithms For Rydberg States, Ulrich D. Jentschura, Peter J. Mohr
Physics Faculty Research & Creative Works
We describe the calculation of hydrogenic (oneloop) Bethe logarithms for all states with principal quantum numbers 200. While, in principle, the calculation of the Bethe logarithm is a rather easy computational problem involving only the nonrelativistic (Schrdinger) theory of the hydrogen atom, certain calculational difficulties affect highly excited states, and in particular states for which the principal quantum number is much larger than the orbital angular momentum quantum number. Two evaluation methods are contrasted. One of these is based on the calculation of the principal value of a specific integral over a virtual photon energy. The other method relies directly ...
SelfEnergy Values For P States In Hydrogen And LowZ Hydrogenlike Ions, Ulrich D. Jentschura, Peter J. Mohr
SelfEnergy Values For P States In Hydrogen And LowZ Hydrogenlike Ions, Ulrich D. Jentschura, Peter J. Mohr
Physics Faculty Research & Creative Works
We describe a nonperturbative (in Z α ) numerical evaluation of the onephoton electron selfenergy for 3P_{1/2} , 3P_{3/2} , 4P_{1/2}, and 4P_{3/2} states in hydrogenlike atomic systems with charge numbers Z = 1 to 5. The numerical results are found to be in agreement with known terms in the expansion of the selfenergy in powers of Z α and lead to improved theoretical predictions for the selfenergy shift of these states.
Muon Transfer From Muonic Hydrogen To Atomic Oxygen And Nitrogen, AnhThu Le, C. D. Lin
Muon Transfer From Muonic Hydrogen To Atomic Oxygen And Nitrogen, AnhThu Le, C. D. Lin
Physics Faculty Research & Creative Works
The results of diabatic hyperspherical closecoupling calculations are presented for the charge exchange of a negative muon from muonic hydrogen to oxygen and nitrogen for collision energies from 10^{3} to 10^{3} eV. It is shown that converged results can be obtained using a much smaller number of channels than in the traditional adiabatic approach. For the energy range below 10 eV our results for nitrogen are in good agreements with the available experimental data and the recent calculations within hyperspherical elliptic coordinates. However, discrepancies were found in the case of oxygen, where a p wave shape resonance is ...
Tunable Conductivity And Conduction Mechanism In An Ultraviolet Light Activated Electronic Conductor, Mariana I. Bertoni, Thomas O. Mason, Julia E. Medvedeva, Arthur J. Freeman, Kenneth R. Poeppelmeier, B. Delley
Tunable Conductivity And Conduction Mechanism In An Ultraviolet Light Activated Electronic Conductor, Mariana I. Bertoni, Thomas O. Mason, Julia E. Medvedeva, Arthur J. Freeman, Kenneth R. Poeppelmeier, B. Delley
Physics Faculty Research & Creative Works
A tunable conductivity has been achieved by controllable substitution of an ultraviolet light activated electronic conductor. The transparent conducting oxide system Hdoped Ca12xMgxAl14O33 (x=0,0.1,0.3,0.5,0.8,1.0) presents a conductivity that is strongly dependent on the substitution level and temperature. Fourpoint dcconductivity decreases with x from 0.26 S/cm (x=0) to 0.106 S/cm (x=1) at room temperature. At each composition the conductivity increases (reversibly with temperature) until a decomposition temperature is reached; above this value, the conductivity drops dramatically due to hydrogen recombination and loss. The observed ...
Breakup Of H₂ In Singly Ionizing Collisions With Fast Protons: ChannelSelective LowEnergy Electron Spectra, Christina Dimopoulou, Robert Moshammer, Daniel Fischer, C. Hohr, Alexander Dorn, Pablo Daniel Fainstein, Jose R. Crespo LopezUrrutia, Claus Dieter Schroter, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich
Breakup Of H₂ In Singly Ionizing Collisions With Fast Protons: ChannelSelective LowEnergy Electron Spectra, Christina Dimopoulou, Robert Moshammer, Daniel Fischer, C. Hohr, Alexander Dorn, Pablo Daniel Fainstein, Jose R. Crespo LopezUrrutia, Claus Dieter Schroter, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich
Physics Faculty Research & Creative Works
The dissociation of H_{2} in singly ionizing collisions with fast protons was analyzed using channelselective lowenergy electron spectra. Dissociative and nondissociative single ionization of H_{2} by 6MeV proton impact was described in a kinematically by determining momentum vectors of electron and H^{+} fragment of H_{2}^{+} target ion, respectively. The electron spectra exhibited role of autoionization of doubly and singly excited states of H_{2}. The doubly and singly excited states of H_{2} involve coupling between electronic and nuclear motion of molecule.
Electronic Structure And LightInduced Conductivity Of A Transparent Refractory Oxide, Julia E. Medvedeva, Arthur J. Freeman, Mariana I. Bertoni, Thomas O. Mason
Electronic Structure And LightInduced Conductivity Of A Transparent Refractory Oxide, Julia E. Medvedeva, Arthur J. Freeman, Mariana I. Bertoni, Thomas O. Mason
Physics Faculty Research & Creative Works
Combined firstprinciples and experimental investigations reveal the underlying mechanism responsible for a drastic change of the conductivity (by 10 orders of magnitude) following hydrogen annealing and UV irradiation in a transparent oxide, 12CaO · 7Al_{2}O_{3}, found by Hayashi et al. [Nature (London) 419, 462 (2002).] The charge transport associated with photoexcitation of an electron from H^{} occurs by electron hopping.We identify the atoms participating in the hops, determine the exact paths for the carrier migration, estimate the temperature behavior of the hopping transport, and predict a way to enhance the conductivity by specific doping.
New Limits On The Drift Of Fundamental Constants From Laboratory Measurements, Marc P. Fischer, Nikolai N. Kolachevsky, Marcus Zimmermann, Ronald Holzwarth, Th H. Udem, Theodor Wolfgang Hansch, Michel Abgrall, Jan Grunert, Ivan Maksimovic, Sebastien Bize, Harold Marion, Franck Pereira M Dos Santos, Pierre Lemonde, Giorgio Santarelli, Ph Laurent, Andre Clairon, Christophe Salomon, Martin K. Haas, Ulrich D. Jentschura, Christoph H. Keitel
New Limits On The Drift Of Fundamental Constants From Laboratory Measurements, Marc P. Fischer, Nikolai N. Kolachevsky, Marcus Zimmermann, Ronald Holzwarth, Th H. Udem, Theodor Wolfgang Hansch, Michel Abgrall, Jan Grunert, Ivan Maksimovic, Sebastien Bize, Harold Marion, Franck Pereira M Dos Santos, Pierre Lemonde, Giorgio Santarelli, Ph Laurent, Andre Clairon, Christophe Salomon, Martin K. Haas, Ulrich D. Jentschura, Christoph H. Keitel
Physics Faculty Research & Creative Works
We have remeasured the absolute 1S2S transition frequency ν_{H} in atomic hydrogen. A comparison with the result of the previous measurement performed in 1999 sets a limit of (29 ± 57) Hz for the drift of ν_{H} with respect to the ground state hyperfine splitting ν_{Cs} in ^{133}Cs. Combining this result with the recently published optical transition frequency in ^{199}Hg^{+} against ν_{Cs} and a microwave ^{87}Rb and ^{133}Cs clock comparison, we deduce separate limits on α˙ / α = (0.9 &plusm; 2.9) x 10^{15} yr^{1} and the fractional time variation of the ...