Two-photon excitation of a single-photon forbidden Auger resonance has been observed and investigated using the intense extreme ultraviolet radiation from the free electron laser in Hamburg. At the wavelength of 26.9 nm (46 eV) two photons promoted a 3d core electron to the outer 4d shell. The subsequent Auger decay, as well as several nonlinear above threshold ionization processes, were studied by electron spectroscopy. The experimental data are in excellent agreement with theoretical predictions and analysis of the underlying multiphoton processes.
COBISS.SI-ID: 23686183
We have measured a series of high-resolution x-ray spectra emitted upon resonant photoexcitation of HCl. The photon energy was tuned across the dissociative 1s›6?* resonance and the Rydberg states, and inelastic photon scattering was observed in the region of KL emission lines. Excellent agreement is found between fully ab initio calculated and measured spectra if interferences between different excitation-emission paths are taken into account. The effect of electronic state interferences is enhanced due to dynamical broadening of the 6?* resonance in HCl.
COBISS.SI-ID: 23925287
X-ray absorption of atomic cesium is measured in the L-edge region, using a beryllium-window cell for cesium vapor and absorption in Xe gas in the same energy region is remeasured with improved signal-to-noise ratio. In both elements, multielectron excitations show the same basic ordering in compact groups, largely independent of the core-hole subshell. The main effect of 6s electron in Cs, apart from 2(s,p)6s excitation, is the enhancement of single- as well as some multielectron resonant channels. The spectra show a convex basic curvature of the L2 and L3 segments, a concave L1 segment.
COBISS.SI-ID: 1539835
The 99.2-eV scattered electrons were detected in coincidence with L3–M23M23 Auger electrons, and the experiment was performed at 343.6- and 344.9-eV electron impact to tune the energy loss to the energy of the dipole-allowed and the dipole-forbidden excitations, respectively. The most intense groups of Auger transitions from [2p3/2]4s (J=1,2) and [2p3/2]4p (J=0,1,2,3) states are identified by comparison with the results of the two-step model, based on distorted-wave Born approximation with exchange and multiconfiguration description of relaxed states.
COBISS.SI-ID: 24351015
Using resonant X-ray photoemission spectroscopy, we determined the relationship between electronic energy level alignment at a metal-molecule interface and single-molecule junction transport data. For three 1,4-benzenediammine/Au systems we show that energy of highest occupied molecular level (HOMO) in molecular films correlates with single molecule dc conductance from STM based break junction experiments, which agrees also with theoretical calculations.
COBISS.SI-ID: 2256484