High Resolution Kb - Spectroscopy and Chemical Environment in Cr Compounds

G. TIRAO; S. LIMANDRI; M TORRES DELUIGI; S. CEPPI; G. STUTZ; J.A. RIVEROS

LNLS,Campinas Brasil

Congreso; Activity Report LNLS 2007; 2008

LNLS

Transitions from the valence band to the 1s level generate chemically sensitive emission lines due to changes in the molecular orbital in different compounds. The electronic configuration of chromium in ground state is [Ar]3d54s1, where the 3d orbital have five unpaired electrons. The 3p!1s transition originates the Kb1;3 line. At energies higher than that of Kb1;3 line, two structures of lines Kb00 and Kb5 appear. The Kb00 line is originated from transitions from molecular orbital ligand-2s to the atomic orbital 1s of the central atom. Thus, its energy has information of the type atom that is bound to the emitting atom, whereas its intensity is related to the number of ligand atoms and the distance of them to the emitting atom [1]. This transition could be considered as an interatomic transition between the ligand and the principal atom. On the other hand, the Kb5 band is formed by transitions from the molecular orbital, with population of 3d and/or 4p of the metal and 2p or 3p of the ligand, to the 1s atomic orbital of metal. The Kb5 band energy shift could be used to determine the oxidation state. In this work, the Kb emission spectra of chromium in compounds with different oxidation states are analyzed. The dependence of the emission line energy and line–width with the oxidation state are characterized. In this work, the Kb emission spectra of chromium in compounds with different oxidation states are analyzed. The dependence of the emission line energy and line–width with the oxidation state are characterized. s level generate chemically sensitive emission lines due to changes in the molecular orbital in different compounds. The electronic configuration of chromium in ground state is [Ar]3d54s1, where the 3d orbital have five unpaired electrons. The 3p!1s transition originates the Kb1;3 line. At energies higher than that of Kb1;3 line, two structures of lines Kb00 and Kb5 appear. The Kb00 line is originated from transitions from molecular orbital ligand-2s to the atomic orbital 1s of the central atom. Thus, its energy has information of the type atom that is bound to the emitting atom, whereas its intensity is related to the number of ligand atoms and the distance of them to the emitting atom [1]. This transition could be considered as an interatomic transition between the ligand and the principal atom. On the other hand, the Kb5 band is formed by transitions from the molecular orbital, with population of 3d and/or 4p of the metal and 2p or 3p of the ligand, to the 1s atomic orbital of metal. The Kb5 band energy shift could be used to determine the oxidation state. In this work, the Kb emission spectra of chromium in compounds with different oxidation states are analyzed. The dependence of the emission line energy and line–width with the oxidation state are characterized.b emission spectra of chromium in compounds with different oxidation states are analyzed. The dependence of the emission line energy and line–width with the oxidation state are characterized.