Le Touquet – Paris-Plage, France
Le Touquet – Paris-Plage, France

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Winters D.F.A.,Helmholtz Center for Heavy Ion Research | Winters D.F.A.,University of Heidelberg | Kuhl Th.,Helmholtz Center for Heavy Ion Research | Kuhl Th.,Mainz University | And 7 more authors.
Physica Scripta T | Year: 2011

Heavy few-electron ions, such as He-, Li- and Be-like ions, are ideal atomic systems to study the effects of correlation, relativity and quantum electrodynamics. Very recently, theoretical and experimental studies of these species achieved a considerable improvement in accuracy. Be-like ions are interesting because their first excited state, i.e. (1s22s2p) 3P0, has an almost infinite lifetime (τ0) in the absence of nuclear spin (I), as it can only decay by a two-photon E1M1 transition to the (1s22s2)1S0 ground state. In addition, the energy difference between the 3P0 and the next higher-lying 3P1 state is expected to remain almost completely unaffected by QED effects, and should thus be dominated by the effects of correlation and relativity. Therefore, we want to determine the (1s22s2p) 3P0-3P1 level splitting in Be-like krypton (84Kr32+), which has I=0, by means of laser spectroscopy at the experimental storage ring at GSI. In such an experiment, the energy splitting can be obtained with very good accuracy and can be compared with recent calculations. © 2011 The Royal Swedish Academy of Sciences.

Evans D.A.,Aberystwyth University | Vearey-Roberts A.R.,Aberystwyth University | Roberts O.R.,Aberystwyth University | Roberts O.R.,Element Six | And 7 more authors.
Journal of Applied Physics | Year: 2013

The transport and optical band gaps for the organic semiconductor tin (II) phthalocyanine (SnPc) and the complete energy band profiles have been determined for organic-inorganic interfaces between SnPc and III-V semiconductors. High throughput measurement of interface energetics over timescales comparable to the growth rates was enabled using in situ and real-time photoelectron spectroscopy combined with Organic Molecular Beam Deposition. Energy band alignment at SnPc interfaces with GaAs, GaP, and InP yields interface dipoles varying from -0.08 (GaP) to -0.83 eV (GaAs). Optical and transport gaps for SnPc and CuPc were determined from photoelectron spectroscopy and from optical absorption using spectroscopic ellipsometry to complete the energy band profiles. For SnPc, the difference in energy between the optical and transport gaps indicates an exciton binding energy of (0.6 ± 0.3) eV. © 2013 AIP Publishing LLC.

Gualtieri A.F.,University of Modena and Reggio Emilia | Canovi L.,University of Modena and Reggio Emilia | Viani A.,University of Modena and Reggio Emilia | Bertocchi P.,Ferrari | And 5 more authors.
Journal of the European Ceramic Society | Year: 2013

This work elucidates the mechanism responsible for the lustre effect of scheelite-based glazes for single-firing wall tiles. The surface decoration is obtained with a thin film composed of a Si-Ca-Zn-Al-K-B frit and 10wt% WO3 on zircon-engobed substrates for single-firing wall tiles (maximum temperature of 1130°C for 50min). The observed lustre effect is sub-adamantine and pearlescent. It is sub-adamantine because scheelite nanocrystals at the surface, with a relatively high refractive index (n=1.93), cause considerable reflection of light. The lustre is also weakly pearlescent because the nano-crystals oriented with the (004) plane parallel to the surface give interference with the underlying glassy layer (n≈1.5), where randomly dispersed scheelite crystals occur. This model apparently applies to the glazes decorated with ceria, although the latter exhibits iridescence due to the high refractive index of ceria (n=2.05) which yields stronger interference effect with the underlying glassy substrate. © 2013 Elsevier Ltd.

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