112,528 research outputs found
Angle- and spin-resolved photoelectron spectroscopy in the region of the 6s6p(2) autoionisation of Tl
No full textMüller M, Böwering N, Svensson A, Heinzmann U. Angle- and spin-resolved photoelectron spectroscopy in the region of the 6s6p(2) autoionisation of Tl. Journal of Physics B: Atomic, Molecular and Optical Physics. 1990;23(13):2267S-2275S.An angle-, energy- and spin-resolved photoionisation experiment was performed in the region of the 6s6p(2)autoionisation resonances of thallium. Using monochromatic circularly polarised synchrotron radiation the energy dependence of the spin-polarisation parameters A, xi and alpha and the angular asymmetry parameter beta of the differential cross section were determined. In the wavelength region investigated these dynamical parameters show a pronounced variation which agrees well with the results of the random phase approximation with exchange' calculation by Cherepkov (1980). A detailed discussion of the resonance behaviour for the autoionising states is given in terms of dipole-matrix elements and phaseshift differences which are extracted from the experimental data
Photoelectron Polarization in Hg 6s-2 Subshell Ionization with Unpolarized Light: New Aspect of the Fano Effect
No full textSchönhense G, Heinzmann U, Kessler J, Cherepkov NA. Photoelectron Polarization in Hg 6s-2 Subshell Ionization with Unpolarized Light: New Aspect of the Fano Effect. Physical review letters. 1982;48(9):603-606
Photoionization of an open-shell atom with open-shell final ionic state: A spin-resolved study of photoelectrons above the Tl+ (6s6p) P-3(1) limit
No full textKuntze R, Salzmann M, Bowering N, Heinzmann U, Cherepkov NA. Photoionization of an open-shell atom with open-shell final ionic state: A spin-resolved study of photoelectrons above the Tl+ (6s6p) P-3(1) limit. In: Journal of Electron Spectroscopy and Related Phenomena. JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. Vol 79. ELSEVIER SCIENCE BV; 1996: 335-338.Spin-resolved measurements of the dynamic photoionization parameters for photoelectrons from thallium atoms are presented for the Tl+ (5d(10)6s6p) P-3(1) final ionic state in the complex spectral region from 90 to 77 nm. For a complete description of this ionization process more than three transition matrix elements are needed since neither the initial nor the final state has closed-shell configuration. An approximate determination of matrix elements and phase shift differences is carried out. In addition, it is discussed how complete information may in principle be obtained
Magnetic-field-averaged photoemission experiments with variable chirality
No full textWe report on a photoemission dichroism effect of magnetic origin which is measured between magnetic field averaged Fe 3p spectra measured with different chirality. By field average we mean the average of two results obtained with opposite directions of magnetization. Field averaging eliminates the linear magnetic dichroism in the angular distribution of photoelectrons, i.e., eliminates the effect of the polarization of the magnetic atoms on the photoemission angular intensity, but the alignment of magnetic moments along the magnetization axis is reflected in a sizeable angular photoemission line shape effect. By changing the chirality of the experiment, i.e., the angle between the magnetization axis and the reaction plane, different intensities are measured from the fine structure of the photoemission peak and a dichroism arises which can be qualitatively understood from atomic photoionization theory. The effect can be exploited to study the magnetic order at antiferromagnetic surfaces as well as to study in plane anisotropy effects on the distribution of magnetic domains in ferromagnets
Fe 2p photoemission magnetic dichroism with linearly polarized synchrotron radiation and with unpolarized Al Kalpha radiation.
No full textAngle- and spin-resolved photoelectron spectroscopy of the Hg 5d10 subshell
No full textSchönhense G, Schäfers F, Heinzmann U, Kessler J. Angle- and spin-resolved photoelectron spectroscopy of the Hg 5d10 subshell. Zeitschrift für Physik A: Hadrons and Nuclei. 1982;304(1):31-40.Parameters describing electron spin polarization in Hg 5d10 subshell photoionization have been measured at rare-gas resonance wavelengths between 73.59 nm and 30.38 nm. The spin parameters as well as asymmetry parameters beta of a recent measurement are discussed in comparison with both nonrelativistic and relativistic ab initio calculations of several authors. The importance of many-electron correlations and spin-orbit coupling effects is considered. We would like to express our thanks to F. Combet Farnoux, N. Cherepkov, W. Johnson and S. Manson for useful correspondence as well as for the communication of unpublished results. This work was supported by the DFG and BMFT. One of us (G.S.) wishes to thank the Studienstiftung des Deutschen Volkes for financial support
Spin-polarised photoelectrons produced from CH3Br molecules by unpolarised and circularly polarised VUV radiation
No full textHeinzmann U, Osterheld B, Schäfers F, Schönhense G. Spin-polarised photoelectrons produced from CH3Br molecules by unpolarised and circularly polarised VUV radiation. Journal of Physics B: Atomic, Molecular and Optical Physics. 1981;14(3):L79-L84.It has been experimentally verified for CH3Br that spin-polarised photoelectrons can be ejected from unoriented molecules if the radiation is circularly polarised or even unpolarised. The polarisation values and the experimental data of the asymmetry parameter beta are discussed by use of Cherenkov's formulae (1981)
New approach for a complete experiment: C1s photoionization in CO2 molecules J. Phys. B: At. Mol. Opt. Phys., 40 (2007) F241-F250.
No full textA Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
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