Electron spectroscopy, combined with synchrotron radiation in the photon-energy range hv=60 -190 eV, was used to measure the angular distributions of Xe 5p and 5s photoelectrons and of N4 500 Auger electrons. The branching ratios and partial cross sections for photoionization and Auger processes were also measured in certain cases. The measured asymmetry parameter P for Sp photoelectrons agrees well with many-electron calculations, which predict a pronounced oscillation in P5p above the 4d ionization threshold due to the 4d-5p intershell interaction. The N4 qOO Auger electrons are produced with photon-energy-dependent anisotropic angular distributions, resulting from alignment of Xe by photoionization. The theoretical analysis of Auger-electron angular distributions is described, and theoretical calculations are found to predict the measured asymmetries well. In addition, Auger-electron peaks were observed to broaden and shift at photon energies near the 4d ionization threshold because of postcollision interaction. The measured shifts of the N~0 lO' So line agree with previous measurements and theory. Electron spectra recorded through the energy region of the 4d~np Rydberg states show that they decay primarily by the Auger process, while the 5p and 5s partial cross sections are relatively weakly affected by autoionization. However, distinct resonance structure was observed in the P parameters for Sp3/2 and Sp~q2 photoelectrons. The measured results are compared with a theoretical calculation of resonant photoionization for the 4d~6p excitation.

Partial photoionization cross sections and angular-distribution asymmetry parameters were determined for Kr 3d photoemission using photon energies of 100 to 280 eV (to 800 eV for the asymmetry parameter). For the 3p subshell, the branching ratio relative to the 3d cross section and the asymmetry parameter were measured using energies of 280 to 800 eV. These results show good agreement with Hartree-Fock-theory predictions at all photon energies. The summed intensity of 4p~np satellites relative to the 3d main line was found to be approximately constant in the photon-energy range 180 -280 eV, and the average asymmetry parameter for these shake-up states showed a marked increase over the same energy range.

The partial cross-section and asymmetry parameters of the 2 s 1 , 2 A 1 and 2 B 2 ionic states of H 2 o+ have been measured at photon energies of 18-31 eV, by time-of-flight photoelectron spectroscopy using synchrotron radiation. The atomic character of the molecular orbitals is discussed in the interpretation of similarities and differences between the measurements for these states. Other synchrotron radiation data, resonance line measurements, and (e,2e) dipole results are ineluded. A multiple-scattering Xa (MSXa) calculation and a ground-state inversion method calculation are in good agreement with our crosssection measurements. There is excellent agreement between experimental asymmetry parameters and those computed from the MSXa method.Stieltjes-Tchebycheff imaging model calculations suggest the presence of resonant channels. This may be the origin of weak resonance structure present in the measurements.