Photoionization of atoms. Final report, April 1, 1976-March 30, 1981

There were two main goals in the experimental study of photoionization. One was to provide accurate data on the results of photon-atom collisions, studying the absolute probability for ejecting electrons from specific orbitals and determining their angular distributions. Also of interest was the probability for one photon to eject two or more electrons. Another goal was to make measurements of specific interactions that would provide sensitive tests for the various theoretical approximations used in calculating photoionization cross sections. To achieve these two goals, care was taken in the selection of the various experiments and in the use of the most appropriate and sophisticated equipment. For example, the techniques of Photoelectron Spectroscopy, Photoionization - Mass Spectrometry, and Synchrotron radiation were used in many of the experiments

RECENT PROGRESS ON THE MEASUREMENT OF ABSOLUTE ATOMIC PHOTOIONIZATION CROSS SECTIONS

Recent measurements of the photoionization cross sections of O, N, and C2 are reviewed and new data are presented for Ne, Ar, Kr , and Xe. These latter results are compared with theory and reveal areas of important disagreement

Experimental characterization of the Xe 5p photoionization by angle- and spin-resolved photoelectron spectroscopy

Heckenkamp C, Schäfers F, Schönhense G, Heinzmann U. Experimental characterization of the Xe 5p photoionization by angle- and spin-resolved photoelectron spectroscopy. Zeitschrift für Physik D: Atoms, Molecules and Clusters. 1986;2(4):257-274.Spin- and angle-resolved photoelectron spectroscopy with elliptically polarized radiation has been used to fully characterize the dynamics of photoelectron emission from free Xe atoms in the 5p-autoionization and continuum region. An advantageous reaction geometry and its experimental realization at the storage ring BESSY are discussed. The three independent experimental parameters which characterize the angular dependence of the photoelectron spin-polarization vector are reported for the wavelength range from 100nm to 40 nm. The results are compared with theoretical predictions based on RRPA-, RPAE- and semiempirical MQDT-calculations. The combination of existing data for the differential photoionization cross section with the spinpolarization parameters is used to completely decouple the photoionization channels: The transition matrix elements and their relative phases are determined separately for every single dissociation channel. The results are discussed in the context of the MQDT. Correlation effects and the influence of spin-orbit interaction on the continuum states most clearly show up when the Dill-Fano angular-momentum-transfer formalism is applied

Angle- and spin-resolved photoelectron spectroscopy of the Hg 5d10 subshell

Schönhense 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