Sergeij A. Krasnikov

Observation of back-donation in 3d metal cyanide complexes through N K absorption spectra

d ¨¨ ¨ Abstract N K and 3d atom L absorption spectra of hexacyano complexes in solid K Fe(CN) , Na Fe(CN) , K Cr(CN) ,

X-ray absorption evidence for the back-donation in iron cyanide complexes

High-resolution, uniformly calibrated Fe 2p3/2 absorption spectra of various Fe(II) and Fe(III) compounds with the metal atom octahedrally coordinated to atomic and molecular ligands are analyzed expecting changes in the absorption spectra due to differences in the formal valence state and in the character of the chemical bond. Particular attention is given to revealing spectral characteristics of the 3dπ–2π(π*) charge transfer (π-back-donation effect) between the iron atom and cyanide ligands.

Electronic structure of FeF2 and FeF3 studied by x-ray absorption and fluorescence spectroscopy

High resolution investigations of polycrystalline FeF2 and FeF3 were performed by means of x-ray absorption and resonant x-ray fluorescence spectroscopy. The obtained F Kα fluorescence spectra of ionic FeF2 and FeF3 were analysed in comparison with the F Kα spectrum of the covalent anion TiF62- in solid K2TiF6. The FKα spectra of compounds under study consist of the main band accompanied by a low-energy shoulder. The latter can be associated with the valence subband of the Fe 3d – F 2p hybridized electron states. Strong high-energy shake-up satellites were observed in the F Kα spectra of these compounds when the excitation energy exceeds the F 1s ionisation threshold (~690 eV). Information about local partial densities of states for FeF2 was obtained from a comparative analysis of Fe L and F K x-ray fluorescence and valence-band photoemission spectra.

Resonant Auger spectroscopy in solid alkali nitrates as a probe of nuclear motion in the core-excited NO3− anion

We investigate the interplay between electronic and nuclear relaxation of the core-excited NO3 anion in solid LiNO3 and NaNO3 by means of the high-resolution X-ray absorption and resonant Auger spectroscopy. It is shown how the relative energy distances between the potential energy surfaces of the intermediate and final states can be mapped using the information on the dispersion of individual participator Auger features upon scanning the photon energy across the resonance. The influence of the cation nature (Li+ or Na+) on the potential surfaces is traced and found to be minimal as a consequence of the rather ionic cation-anion interaction