The dynamics of the photoionization of the two outermost orbitals of C(60) has been studied in the oscillatory regime from threshold to the carbon K edge. We show that geometrical properties of the fullerene electronic hull, such as its diameter and thickness, are contained in the partial photoionization cross sections by examining ratios of partial cross sections as a function of the photon wave number in the Fourier conjugated space. Evaluated in this unconventional manner photoemission data reveal directly the desired spatial information.

Inner-shell photoelectron spectra of the N 1s level in N 2 have been measured with sufficient resolution to resolve the splitting between the gerade and ungerade components. The selective enhancement of the gerade component on the N 2 σ shape resonance is clearly seen, confirming that the resonant behavior is mainly caused by the σ u channel. The splitting of the two components is found to be 97(3) meV.

The absolute photoabsorption cross section of benzene (C6H6), encompassing the C 1s−1 π*e2u resonance, the C 1s threshold, the satellite thresholds, and extending up to 800 eV, has been measured using synchrotron radiation. Measurements of the discrete absorption structure from below the C 1s ionization threshold have been performed at high resolution. In order to unambiguously assign all structure present in the photoabsorption cross section, C 1s photoelectron spectra were measured from the C 1s threshold region up to 350 eV along with satellite spectra. The C 1s−1 single-hole and the satellite cross sections have been derived in absolute units, and their angular distributions have been determined. Resonant and normal Auger spectra were taken on the main features of the photoabsorption and single-hole cross sections. From the best resolved photoelectron spectra the underlying structure in the asymmetric benzene photoelectron peak can be partly disentangled. The experimental data show that at least two vibrational modes play a role in the C 1s photoelectron spectrum. The behavior of the investigated shake-up structure closely resembles that of ethene and ethyne, where the satellite bands due to π→π* excitations gain intensity towards threshold, an observation which may be attributed to conjugate shake-up processes. These processes lead to a significant contribution of the satellite intensity to the production of the absorption features traditionally assigned to the carbon shape resonances in benzene. An EXAFS analysis of the wide range oscillations present on the photoabsorption cross section has been performed, and reveals the C–C nearest-neighbor distance.

The 3d photoelectron spectrum of xenon has been measured at several photon energies in the immediate threshold region. The absolute photoionization cross section and angular anisotropy parameter ␤ have been determined for the two spin-orbit-split components. The experimental results are compared with calculations using a relaxed single-channel approximation. In agreement with theory, most abrupt changes in cross section and angular distribution are observed just above threshold. However, the Xe 3d 5/2 photoionization cross section also reveals, some 30-eV above threshold a second maximum that has not been predicted theoretically.

Resonant photofragmentation of core-excited water molecules has been studied with high-resolution partialion-yield spectroscopy. Both the single and coincidence channels were monitored simultaneously. A steep increase in the coincidence yield curves above the ionization threshold, where the normal Auger decay produces doubly charged or multiply charged species that yield two or more charged fragments, has been observed. By comparing the single and coincidence channels the relative weight of H neutral fragments has been qualitatively assessed, and found to be higher for the O 1s→4a 1 primary excitation. The presented ion-yield data provide strong evidence for a branching between atomic Auger decay and molecular fragmentation in the O ϩ channel. The most unexpected result is the formation of H 2 ϩ species being detected and attributed to a highly excited bending mode. ͓S1050-2947͑99͒00601-0͔