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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Breakup Of H₂ In Singly Ionizing Collisions With Fast Protons: Channel-Selective Low-Energy Electron Spectra, Christina Dimopoulou, Robert Moshammer, Daniel Fischer, C. Hohr, Alexander Dorn, Pablo Daniel Fainstein, Jose R. Crespo Lopez-Urrutia, Claus Dieter Schroter, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich
Breakup Of H₂ In Singly Ionizing Collisions With Fast Protons: Channel-Selective Low-Energy Electron Spectra, Christina Dimopoulou, Robert Moshammer, Daniel Fischer, C. Hohr, Alexander Dorn, Pablo Daniel Fainstein, Jose R. Crespo Lopez-Urrutia, Claus Dieter Schroter, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich
Physics Faculty Research & Creative Works
The dissociation of H2 in singly ionizing collisions with fast protons was analyzed using channel-selective low-energy electron spectra. Dissociative and nondissociative single ionization of H2 by 6MeV proton impact was described in a kinematically by determining momentum vectors of electron and H+ fragment of H2+ target ion, respectively. The electron spectra exhibited role of autoionization of doubly and singly excited states of H2. The doubly and singly excited states of H2 involve coupling between electronic and nuclear motion of molecule.
Electronic Structure And Light-Induced Conductivity Of A Transparent Refractory Oxide, Julia E. Medvedeva, Arthur J. Freeman, Mariana I. Bertoni, Thomas O. Mason
Electronic Structure And Light-Induced Conductivity Of A Transparent Refractory Oxide, Julia E. Medvedeva, Arthur J. Freeman, Mariana I. Bertoni, Thomas O. Mason
Physics Faculty Research & Creative Works
Combined first-principles 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 · 7Al2O3, 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.
Electron Self-Energy For Higher Excited S Levels, Ulrich D. Jentschura, Peter J. Mohr
Electron Self-Energy For Higher Excited S Levels, Ulrich D. Jentschura, Peter J. Mohr
Physics Faculty Research & Creative Works
A nonperturbative numerical evaluation of the one-photon electron self-energy for the 3S and 4S states with charge numbers Z=1 to 5 is described. The numerical results are in agreement with known terms in the expansion of the self-energy in powers of Zα.
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 1S-2S transition frequency νH 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 νH with respect to the ground state hyperfine splitting νCs in 133Cs. Combining this result with the recently published optical transition frequency in 199Hg+ against νCs and a microwave 87Rb and 133Cs clock comparison, we deduce separate limits on α˙ / α = (-0.9 &plusm; 2.9) x 10-15 yr-1 and the fractional time …
Protonium Formation In The P̅-H Collision At Low Energies By A Diabatic Approach, M. Hesse, Anh-Thu Le, C. D. Lin
Protonium Formation In The P̅-H Collision At Low Energies By A Diabatic Approach, M. Hesse, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
We present a diabatization technique in combination with the recently developed hyperspherical close coupling (HSCC) method. In contrast to the strict diabatization, our simple diabatization procedure transforms only sharp avoided crossings in the adiabatic hyperspherical potential curves into real crossings. With this approach, the weak collision channels can be removed from the close-coupling calculations. This method is used to study the antiproton-hydrogen collision at low energies. In the case of a scaled down (anti)proton mass, we show that a 10-channel calculation is enough to obtain converged cross sections at low energies. The results also indicate that protonium formation occurs mostly …
Self-Energy Correction To The Two-Photon Decay Width In Hydrogenlike Atoms, Ulrich D. Jentschura
Self-Energy Correction To The Two-Photon Decay Width In Hydrogenlike Atoms, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
We investigate the guage invariance of the leading logarithmic radiative correction to the two-photon decay width in hydrogenlike atoms, was investigated. The effective treatment of the correction using a Lamb-shift led to the equivalent results in both the length and velocity gages. The relevant radiative corrections were found to be related to the energies that entered into the propagator denominators, to the Hamiltonian, to the wave functions, and to the energy conservation condition, that holds between two photons. The results show that the dominant radiative correction to the 2S two-photon decay width is about -2.020 536(α/π)(Zα)2 1n[(Zα)-2] …