High resolution Kbeta-spectroscopy and chemical environment in Cr compounds

G. TIRAO; M TORRES DELUIGI; G. STUTZ; J.A. RIVEROS

Campinas

Congreso; XVII Reunión Anual de Usuarios del LNLS; 2007

LNLS

The Kb spectrum of several Cr compounds exhibiting di®erent oxidation state wasmeasured using a high resolution spectrometer [1] at the XRD1 beamline. Theenergy diference between the Kb1; 3 and the Kb2; 5 lines varies with the oxidationstate according to ¢E(CrIII ) > ¢E(Cr0) > ¢E(CrV I ). We found that this energydiference is very sensitive with the oxidation state, so that it could be used toexperimentally determine oxidation states with an accuracy higher than using theabsolute position of the Kb1; 3 peak, as suggested in previous works [2,3,4]. Thelinewidht of the Kb1; 3 peak increases linearly with increasing oxidation state (from1.81 eV for Cr0 to 2.68 eV for CrV I ). The Kb" satellite line was measured to beshifted about 16 eV from the Kb2; 5 line, which is in agreement with the type ofligand atom (oxygen) in the investigated Cr compounds. The normalized intensityof the Kb" line decreases exponentially with the Cr{O distance, as previously foundin Mn compounds [5]. This relation could be used as a tool to determine bondlengths with an accuracy better than 0.1ºA.