An apparatus for the production of circularly polarised VUV radiation

Heinzmann U. An apparatus for the production of circularly polarised VUV radiation. Journal of Physics E: Scientific Instruments. 1977;10(10):1001-1005.An apparatus for the production of circularly polarised vacuum ultraviolet (VUV) radiation up to 9 eV is described. A photon beam of high intensity and polarisation is used for the photoionisation of atomic and molecular vapour beams in order to obtain spin-polarised photoelectrons. The radiation source and the polariser are discussed in detail. Results of intensity and polarisation measurements are presented

Determination of partial photoionisation cross sections of methyl bromide in the first autoionisation range by use of spin polarisation photoelectron spectroscopy

Schäfers F, Baig MA, Heinzmann U. Determination of partial photoionisation cross sections of methyl bromide in the first autoionisation range by use of spin polarisation photoelectron spectroscopy. Journal of Physics B: Atomic, Molecular and Optical Physics. 1983;16(1):L1-L6.Using recent experimental data on photoelectron spin polarisation combined with the high-resolution spectrum of methyl bromide, which has also been recently reported, the partial photoionisation cross sections for the ionisation of CH3Br from the 4 pi ground-state orbital into the energy degenerate continua epsilon sigma , epsilon pi and epsilon delta have been determined separately. Quantitative results, obtained for the autoionising resonances between 116 and 118 nm, are reported and discussed

Spin polarization of Auger- and of photoelectrons from barium atoms exposed to circularly polarized radiation and their cross comparison

Kuntze R, Salzmann M, Böwering N, Heinzmann U. Spin polarization of Auger- and of photoelectrons from barium atoms exposed to circularly polarized radiation and their cross comparison. Zeitschrift für Physik D: Atoms, Molecules and Clusters. 1994;30(2-3):235-237.New results of spin polarization of both photoelectrons and Auger electrons are reported after 5[Rho] photoionization of free Ba atoms with circularly polarized light. A substantial polarization transfer from the spin polarized photons to the spin polarized photoelectrons and via the hole state orientation to the spin polarized Auger-electrons is observed. The cross comparison of the results for photoelectrons and Auger-electrons allows a quantitative test of the assumed two step model where both electron-emission processes occur in sequence

Angle and spin resolved Auger and photoelectron spectroscopy on Rb-layers by means of circularly polarized VUV radiation

Stoppmanns 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

Angle- and spin-resolved photoelectron spectroscopy in the region of the 6s6p(2) autoionisation of Tl

Müller 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

Spin polarized photoelectrons with unpolarized light in normal emission from Pt(110)

Irmer N, Frentzen F, Schmiedeskamp B, Heinzmann U. Spin polarized photoelectrons with unpolarized light in normal emission from Pt(110). Surface Science. 1994;307-309(2):1114-1117.The normally emitted photoelectrons of the reconstructed (1 x 2) surface of Pt(110) caused by off-normally incoming, unpolarized light are spin polarized. Measurements have been performed with the light of a gas discharge tube and spin polarization of up to 20% has been found for the spin polarization perpendicular to the reaction plane, defined by the momenta of incoming photon and outgoing electron beam. The polarization depends significantly on a rotation of the crystal about the surface normal. The experimental data are in good agreement with theoretical calculations of Feder's group [1] based upon the theory describing the photoemission in the one-step model

Spin-resolved photoemission from Pd(111)

Schmiedeskamp B, Kessler B, Müller N, Schönhense G, Heinzmann U. Spin-resolved photoemission from Pd(111). Solid State Communications. 1988;65(7):665-670

Electronic Resonances in Rare-Gas Adsorbates Observed by Spin-Resolved Electron Spectroscopy

Schönhense G, Kessler B, Müller N, Schmiedeskamp B, Heinzmann U. Electronic Resonances in Rare-Gas Adsorbates Observed by Spin-Resolved Electron Spectroscopy. Physica Scripta. 1987;35(4):541-546

Photoelectron spin polarization approaching unity: photoionization of TI

Böwering N, Salzmann M, Müller M, Klausing H-W, Heinzmann U. Photoelectron spin polarization approaching unity: photoionization of TI. Physica Scripta. 1990;41(4):429-432.It is shown that a complete photoelectron-spin polarization occurs independent of emission angle for two special sets of values of the dynamical photoionization parameters. In spin- and angle-resolved photoelectron spectroscopy of thallium the dynamical parameters were measured near the autoionization resonances at 149 nm and 82 nm. A pronounced angular variation of the polarization component A[Theta] was observed at 83 nm. For both resonances the parameters were found to approach different limiting values such that the length of the spin-polarization vector assumes values close to unity at all emission angles. The implications of these results for the corresponding dipole transition matrix elements are discussed