Time-differential Mössbauer emission spectroscopy: Development of a new spectrometer and first results

A spectrometer for time-differential Mossbauer spectroscopy was developed with a high count rate capability, a good time resolution, and a flexible data handling. Chemical and physical aftereffects following the57Co decay were studied within the cobalt doped systems Turnbulls blue and ZnS.

Advances in Mössbauer Emission Spectroscopy

After effects following nuclear transformation have been extensively studied in a large variety of matrices by Mossbauer Emission Spectroscopy (MES). The branching ratios of transient atomic charge states and energetically unstable states of the environment, excitations of electronic ligand field states and populations out of equilibrium within the electronic ground state manifold have been studied. Recent developments and also new insights and understandings of different aspects of the aftereffects of radioactive decay of57Co in semiconductors and molecular crystals are reviewed. A detailed picture of the decay process within the electronic states of the nucleogenic Fe3+ species could be o…

A M�ssbauer and ESR study of LiNbO3-Fe2O3 for low Fe2O3 concentrations

Samples of the system LiNbO3-Fe2O3 prepared by water quenching and by the double-roller quenching method in the range up to 24 mol% Fe2O3 were investigated by Mossbauer and ESR spectroscopy. In the water quenched samples up to 11 mol% Fe2O3 only the Fe3+ and the Fe2+ valence states could be detected. The Fe2+ concentration decreased with increasing Fe2O3 content. Above 11 mol% Fe2O3 magnetically split Mossbauer spectra indicated the presence of Fe2O3 clusters. The isomer shift values of Fe3+ as a function of Fe2O3 concentration showed jumps at 6 and 11 mol% Fe2O3, whereas no significant changes could be detected in the quadrupole splitting values. The ESR data already exhibited the existenc…

Metastable electronic states induced by nuclear decay and light

Radioactive atoms incorporated in insulating solid-state compounds create various kinds of chemical and physical “after-effects” upon nuclear disintegration. Mossbauer emission spectroscopy of57Co-labelled coordination compounds has undoubtedly become the most informative technique to detect such after-effects like aliovalent charge and spin states of the nucleogenic iron atom resulting from the57Co(EC)57Fe decay, low energy excitations of crystal field and Zeeman states, linkage isomerism, radical formation with subsequent redox reactions, and others. We have extensively studied57Co-labelled complexes with [CoIIN6] cores employing time-integral and time-resolved Mossbauer emission spectros…

Poster contributions

Mössbauer Spectroscopic Evidence of Angle-Dependent Intersystem Crossing in LiNbO3:Fe3+

M\"ossbauer emission spectra of LiNb${\mathrm{O}}_{3}$:$^{57}\mathrm{Co}$ single crystals in magnetic fields up to 5 T at 4.2 K show initial populations of the $^{6}A_{1\mathrm{g}}$ Zeeman substates of ${\mathrm{Fe}}^{3+}$ which depend strongly on the angle between the crystallographic $c$ axis and the magnetic field. This is interpreted in terms of a crystal-field effect on excited states which influences the initial populations of the Zeeman sublevels of the $^{6}A_{1\mathrm{g}}$ ground term after the electron-capture decay of $^{57}\mathrm{Co}$. An intersystem crossing process due to orbit-lattice interaction can fairly well explain the angular dependence.

CCDC 105849: Experimental Crystal Structure Determination

Related Article: O.Franke, B.E.Wiesler, N.Lehnert, C.Nather, V.Ksenofontov, J.Neuhausen, F.Tuczek|2002|Inorg.Chem.|41|3491|doi:10.1021/ic0111987

CCDC 190506: Experimental Crystal Structure Determination

Related Article: O.Franke, B.E.Wiesler, N.Lehnert, C.Nather, V.Ksenofontov, J.Neuhausen, F.Tuczek|2002|Inorg.Chem.|41|3491|doi:10.1021/ic0111987