655 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
Angle and spin resolved Auger and photoelectron spectroscopy on Rb-layers by means of circularly polarized VUV radiation
No full textStoppmanns P, David R, Müller N, Heinzmann U. Angle and spin resolved Auger and photoelectron spectroscopy on Rb-layers by means of circularly polarized VUV radiation. Zeitschrift für Physik D: Atoms, Molecules and Clusters. 1994;30(2-3):251-253.Normal incidence circularly polarized VUV radiation with energies around 23 eV creates spin polarized photoelectrons from thick layers of Rb on Pt(111) and thus excites oriented 4[Rho] hole states. The preferential spin direction of the Auger electrons and its dependence upon the emission angle has been measured and is compared with the corresponding angular dependence of the primary photoelectron spin polarization also measured. Since the CVV Auger decay relates to a s2 pair of valence electrons, the cross comparison of results for photoelectrons and Auger electrons studies the questions on whether photoemission and Auger decay occur in sequence, assuming an independent two step model, and whether the valences-electrons couple to a singlet state configuration
Energy dependence of the electron spin polarisation parameters for Hg 5d photoionisation with circularly polarised light
No full textSchäfers F, Heckenkamp C, Schönhense G, Heinzmann U. Energy dependence of the electron spin polarisation parameters for Hg 5d photoionisation with circularly polarised light. Journal of Physics B: Atomic, Molecular and Optical Physics. 1988;21(5):769-774.Circularly polarised VUV radiation from the storage ring BESSY was used to measure all three spin polarisation parameters of photoelectrons from the Hg 5d shell in the photon energy range from threshold to approximately 35 eV. The experimental results are compared with theoretical calculations in the relativistic and non-relativistic random-phase-approximation scheme (RRPA and RPAE respectively) and Dirac-Slater (DS) calculations. A discussion of the influence of relativistic and potential barrier effects on the experimental data is given
Angle- 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-resolved photoionisation of lead above the Pb+ (6s26p) 2P3/2 - threshold
No full textMüller M, Böwering N, Schäfers F, Heinzmann U. Spin-resolved photoionisation of lead above the Pb+ (6s26p) 2P3/2 - threshold. Physica Scripta. 1990;41(1):38-41
Schönhense and Heinzmann Respond
No full textSchönhense G, Heinzmann U. Schönhense and Heinzmann Respond. Physical review letters. 1986;57(2):268.Response to a comment of C. P. Flynn to Sharp Photon-Induced np - (n+1)s Resonances in Xe and Kr Monolayers Observed by Spin-Resolved Electron Spectroscopy in Physical Review Letters 57, 267 (1986)
The spin-orbit splitting in the Si bandstructure measured by means of spin-resolved photoemission
No full textSchmiedeskamp B, Vogt B, Heinzmann U. The spin-orbit splitting in the Si bandstructure measured by means of spin-resolved photoemission. Solid State Communications. 1990;76(12):1391-1394
Photoelectron angular distributions from laser-excited aligned Yb atoms ionized by vacuum ultraviolet radiation
No full textKerling C, Böwering N, Heinzmann U. Photoelectron angular distributions from laser-excited aligned Yb atoms ionized by vacuum ultraviolet radiation. Journal of Physics B: Atomic, Molecular and Optical Physics. 1990;23(20):L629-L635
Analysis of autoionization resonances in the Hg 6s2-photoionization by measurements of photoelectron polarization
No full textSchäfers F, Schönhense G, Heinzmann U. Analysis of autoionization resonances in the Hg 6s2-photoionization by measurements of photoelectron polarization. Zeitschrift für Physik A: Hadrons and Nuclei. 1982;304(1):41-48.Measurements of the spin polarization of photoelectrons in the autoionization region of the Hg 6s2-subshell using circularly polarized synchrotron radiation and using unpolarized light from rare gas discharge lamps are reported. The results obtained show a pronounced structure across the resonances. Together with data of the cross section and its angular distribution these data from a complete parameter set for the determination of the transition matrix elements and the phase difference of the continuum wavefunctions. Evidences for strong configuration interaction and channel mixing between the open and closed channels were found. The matrix elements and their ratio vary strongly across the resonances and the relative phase shows some changes of sign. A change of the relative phase by Pi across an autoionization resonance, predicted by Fano, has been verified experimentally for the triplet resonance. We would like to express our gratitude to Professors W. Paul, G. Nöldeke and J. Kessler for their continued interest and encouragement. We thank Dr. D. Husmann, Dr. J. Hormes and B. Osterheld for their assistance in performing the experiment in Bonn. We are grateful to Dr. N.A. Cherepkov for helpful discussions and acknowledge support by the DFG and BMFT
Spin-resolved photoelectron spectroscopy of HBr in the resonance region of electron autoionization
No full textSalzmann M, Böwering N, Klausing H-W, Kuntze R, Heinzmann U. Spin-resolved photoelectron spectroscopy of HBr in the resonance region of electron autoionization. Journal of Physics B: Atomic, Molecular and Optical Physics. 1994;27(10):1981-1992
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