11 research outputs found
Resonant inelastic soft-x-ray scattering spectra at the N1s and C1s edges of poly(pyridine-2,5-diyl)
Resonant inelastic scattering measurements of poly(pyridine-2,5-diyl) have
been performed at the N1s and C1s edges using synchrotron radiation. For
comparison, molecular orbital calculations of the spectra have been carried out
with the repeat unit as a model molecule of the polymer chain. The resonant
emission spectra show depletion of the p electron bands which is consistent
with symmetry selection and momentum conservation rules. The depletion is most
obvious in the resonant inelastic scattering spectra of carbon while the
nitrogen spectra are dominated by lone pair n orbital emission of s symmetry
and are less excitation energy dependent. By comparing the measurements to
calculations an isomeric dependence of the resonant spectra is found giving
preference to two of the four possible isomers in the polymer.Comment: 6 pages, 3 figures,
http://www.sciencedirect.com/science/article/pii/S036820489800354
Generalization of the duration-time concept for interpreting state of the art high resolution resonant photoemission spectra
The duration-time concept, vastly successful for interpreting the frequency dependence of resonant radiative and nonradiative x-ray scattering spectra, is tested for fine-scale features that can be obtained with state of the art high-resolution spectroscopy. For that purpose resonant photoelectron (RPE) spectra of the first three outermost singly ionized valence states X 2Σg+, A 2Πu, and B 2Σu+, are measured for selective excitations to different vibrational levels (up to n=13) of the N 1s→π* photoabsorption resonance in N2 and for negative photon frequency detuning relative to the adiabatic 0-0 transition of this resonance. It is found that different parts of the RPE spectrum converge to the spectral profile of direct photoionization (fast scattering) for different detunings, and that the RPE profiles are asymmetrical as a function of frequency detuning. The observed asymmetry contradicts the picture based on the simplified notation of a common scattering duration time, but is shown to agree with the here elaborated concept of partial and mean duration times. Results of the measurements and the simulations show that the duration time of the scattering process varies for different final electronic and different final vibrational states. This owes to two physical reasons: one is the competition between the fast “vertical” and the slow “resonant” scattering channels and the other is the slowing down of the scattering process near the zeros of the real part of the scattering amplitude
Compatibility of quantitative X ray spectroscopy with continuous distribution models of water at ambient conditions
Anomalous polarization dependence in vibrationally resolved resonant inelastic X-ray scattering of H2O
It is well established that different electronic channels, in resonant inelastic x-ray scattering (RIXS), display
different polarization dependences due to different orientations of their corresponding transition dipole moments
in the molecular frame. However, this effect does not influence the vibrational progression in the Franck-Condon
approximation. We have found that the transition dipole moments of core excitation and deexcitation experience
ultrafast rotation during dissociation in the intermediate core-excited state. This rotation makes the vibrational
progression in RIXS sensitive to the polarization of the x-ray photons.We study the water molecule, in which the
effect is expressed in RIXS through the dissociative core-excited state where the vibrational scattering anisotropy
is accompanied also by violation of parity selection rules for the vibrations