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Start Over Author "O. Wilhelmi" Journal physical review letters
4 results on '"O. Wilhelmi"'

1. Manifestation of Strongly Delocalized Atomic States in the5sPhotoionization of Xenon

Author

O. Wilhelmi, G. Reichardt, G. Mentzel, K.-H. Schartner, F. Vollweiler, S Lauer, I. D. Petrov, B. M. Lagutin, V. L. Sukhorukov, and H. Schmoranzer

Subjects
Physics, Delocalized electron, Xenon, Electronic correlation, chemistry, Atom, General Physics and Astronomy, chemistry.chemical_element, Photoionization, Atomic physics, Resonance (chemistry), Spectroscopy, Fluorescence spectroscopy
Abstract

The photoionization (PI) of the Xe atom was investigated in the vicinity of the 5s -shell threshold by photon-induced fluorescence spectroscopy. The highest resolution so far attained of 2meV enabled us to observe a new series of resonance structures in the 5s -PI cross section closely above threshold. Calculations of the partial 5s - and 5p -PI cross sections were performed taking into account many-electron correlations. These structures were related with strongly delocalized f -resonances which affect the 5s -PI cross section due to their mixing with p -resonances. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997
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2. Terahertz response of a microfabricated rod-split-ring-resonator electromagnetic metamaterial

Author

O. Wilhelmi, B T Saw, Bernard D. Casse, and Herbert O. Moser

Subjects
Physics, Wave propagation, Orders of magnitude (temperature), Terahertz radiation, business.industry, General Physics and Astronomy, Metamaterial, Split-ring resonator, Optics, Far infrared, Quasiparticle, Metamaterial absorber, Atomic physics, business
Abstract

The first electromagnetic metamaterials (${\mathrm{E}\mathrm{M}}^{3}$) produced by microfabrication are reported. They are based on the rod--split-ring-resonator design as proposed by Pendry et al. [IEEE Trans. Microwave Theory Tech. 47, 2075 (1999)] and experimentally confirmed by Smith et al. [Phys. Rev. Lett. 84, 4184 (2000)] in the GHz frequency range. Numerical simulation and experimental results from far infrared (FIR) transmission spectroscopy support the conclusion that the microfabricated composite material is ${\mathrm{E}\mathrm{M}}^{3}$ in the range 1--2.7 THz. This extends the frequency range in which ${\mathrm{E}\mathrm{M}}^{3}$ are available by about 3 orders of magnitude well into the FIR, thereby widely opening up opportunities to verify the unusual physical implications on electromagnetic theory as well as to build novel electromagnetic and optical devices.

Published
2003

3. Search for a dark matter annihilation signal from the galactic center halo with H.E.S.S.

Author

Abramowski A, Acero F, Aharonian F, Akhperjanian AG, Anton G, Barnacka A, de Almeida UB, Bazer-Bachi AR, Becherini Y, Becker J, Behera B, Bernlöhr K, Bochow A, Boisson C, Bolmont J, Bordas P, Borrel V, Brucker J, Brun F, Brun P, Bulik T, Büsching I, Carrigan S, Casanova S, Cerruti M, Chadwick PM, Charbonnier A, Chaves RC, Cheesebrough A, Chounet LM, Clapson AC, Coignet G, Conrad J, Dalton M, Daniel MK, Davids ID, Degrange B, Deil C, Dickinson HJ, Djannati-Ataï A, Domainko W, Drury LO, Dubois F, Dubus G, Dyks J, Dyrda M, Egberts K, Eger P, Espigat P, Fallon L, Farnier C, Fegan S, Feinstein F, Fernandes MV, Fiasson A, Fontaine G, Förster A, Füssling M, Gallant YA, Gast H, Gérard L, Gerbig D, Giebels B, Glicenstein JF, Glück B, Goret P, Göring D, Hague JD, Hampf D, Hauser M, Heinz S, Heinzelmann G, Henri G, Hermann G, Hinton JA, Hoffmann A, Hofmann W, Hofverberg P, Horns D, Jacholkowska A, de Jager OC, Jahn C, Jamrozy M, Jung I, Kastendieck MA, Katarzyński K, Katz U, Kaufmann S, Keogh D, Kerschhaggl M, Khangulyan D, Khélifi B, Klochkov D, Kluźniak W, Kneiske T, Komin N, Kosack K, Kossakowski R, Laffon H, Lamanna G, Lennarz D, Lohse T, Lopatin A, Lu CC, Marandon V, Marcowith A, Masbou J, Maurin D, Maxted N, McComb TJ, Medina MC, Méhault J, Moderski R, Moulin E, Naumann CL, Naumann-Godo M, de Naurois M, Nedbal D, Nekrassov D, Nguyen N, Nicholas B, Niemiec J, Nolan SJ, Ohm S, Olive JF, Wilhelmi Ede O, Opitz B, Ostrowski M, Panter M, Arribas MP, Pedaletti G, Pelletier G, Petrucci PO, Pita S, Pühlhofer G, Punch M, Quirrenbach A, Raue M, Rayner SM, Reimer A, Reimer O, Renaud M, de los Reyes R, Rieger F, Ripken J, Rob L, Rosier-Lees S, Rowell G, Rudak B, Rulten CB, Ruppel J, Ryde F, Sahakian V, Santangelo A, Schlickeiser R, Schöck FM, Schönwald A, Schwanke U, Schwarzburg S, Schwemmer S, Shalchi A, Sikora M, Skilton JL, Sol H, Spengler G, Stawarz Ł, Steenkamp R, Stegmann C, Stinzing F, Sushch I, Szostek A, Tavernet JP, Terrier R, Tibolla O, Tluczykont M, Valerius K, van Eldik C, Vasileiadis G, Venter C, Vialle JP, Viana A, Vincent P, Vivier M, Völk HJ, Volpe F, Vorobiov S, Vorster M, Wagner SJ, Ward M, Wierzcholska A, Zajczyk A, Zdziarski AA, Zech A, and Zechlin HS

Abstract

A search for a very-high-energy (VHE; ≥100  GeV) γ-ray signal from self-annihilating particle dark matter (DM) is performed towards a region of projected distance r∼45-150  pc from the Galactic center. The background-subtracted γ-ray spectrum measured with the High Energy Stereoscopic System (H.E.S.S.) γ-ray instrument in the energy range between 300 GeV and 30 TeV shows no hint of a residual γ-ray flux. Assuming conventional Navarro-Frenk-White and Einasto density profiles, limits are derived on the velocity-weighted annihilation cross section (σv) as a function of the DM particle mass. These are among the best reported so far for this energy range and in particular differ only little between the chosen density profile parametrizations. In particular, for the DM particle mass of ∼1  TeV, values for (σv) above 3×10(-25)  cm(3) s(-1) are excluded for the Einasto density profile.

Published
2011
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4. Terahertz response of a microfabricated rod-split-ring-resonator electromagnetic metamaterial.

Author

Moser HO, Casse BD, Wilhelmi O, and Saw BT

Abstract

The first electromagnetic metamaterials (EM3) produced by microfabrication are reported. They are based on the rod-split-ring-resonator design as proposed by Pendry et al. [IEEE Trans. Microwave Theory Tech. 47, 2075 (1999)] and experimentally confirmed by Smith et al. [Phys. Rev. Lett. 84, 4184 (2000)] in the GHz frequency range. Numerical simulation and experimental results from far infrared (FIR) transmission spectroscopy support the conclusion that the microfabricated composite material is EM3 in the range 1-2.7 THz. This extends the frequency range in which EM3 are available by about 3 orders of magnitude well into the FIR, thereby widely opening up opportunities to verify the unusual physical implications on electromagnetic theory as well as to build novel electromagnetic and optical devices.

Published
2005
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