ABSTRACT: This paper summarizes recent developments for experimental and theoretical studies on core-level
photoelectron spectroscopy of N2. Analysis of experimental spectra reveals that the 1σg and
1σu core-hole states differ in energy by ~100meV and in equilibrium bond length by ~0.04pm,
in agreement with ab initio predictions. The ratio of the 1σg and 1σu photoionization cross sections
measured in the photon energy range up to 1 keV reveals oscillatory structure due to two-center interference, equivalent to
double-slit experiment, as Cohen and Fano predicted. The experimental Auger rates for the transition to the dicationic ground
are found to be different by a factor of two for 1σg and 1σu hole states and are well reproduced by the
ab initio calculations. All these findings support the delocalized picture of the core hole. Discussion is given how many-body
processes involved and observations for these processes affect the observation of the localized and/or delocalized core hole.
The European Physical Journal Special Topics 04/2012; 169(1):95-107. · 1.56 Impact Factor
Physical Review A. 76(6):62704.
ABSTRACT: Core-level photoemission from N2 can be considered as an analogue of Young’s double-slit experiment (YDSE) in which the double-slit is replaced by a pair of N 1s orbitals. N 1s photoelectron spectra of N2 are measured in the extended photon energy region up to ∼ 1 keV at unprecedented resolution. The measured ratio between the 1σg and 1σu photoionization cross-sections oscillates as a function of electron momentum due to interference effects analogue to YDSE. We found a shift of the interference pattern with respect to a prediction by a simple model for coherent two-center emission, the Cohen–Fano formula, and attributed it to photoelectron scattering by the neighboring atom. We demonstrate that the shift can be used to determine the scattering phase of the photoelectron.
Journal of Electron Spectroscopy and Related Phenomena.
ABSTRACT: X-ray photoelectron spectra of the N2 molecule are studied both experimentally and theoretically in the extended energy region up to 1 keV. The ratio of the photoionization cross sections for the gerade and ungerade core levels displays a modulation in the high energy region caused by the two-center interference, as predicted by Cohen and Fano (CF) in 1966. The physical background of this CF effect is the same as in Young’s double-slit experiment. We have found that the interference pattern deviates significantly from the CF prediction. The origin of such a breakdown of the CF formula is the scattering of the photoelectron inside the molecule and the momentum transfer from the emitted fast photoelectron to the nuclei. Usually the recoil effect is small. We show that the electron recoil strongly affects the two-center interference pattern. Both stationary and dynamical aspects of the recoil effect shed light on the role of the momentum exchange in the two-center interference.