X-ray absorption spectra of chlorine K edge, ruthenium LIII edge, and rhodium LIII edge from (NH4)3[RhCl6], K3[RuCl6], and [Ru(NH3)6]Cl3 have been measured with a Johann-type 50 cm bent crystal vacuum spectrograph. The white lines due to the transitions to the incompletely filled antibonding molecular orbital (MO) 2t2g(π*) or nonbonding orbital t2g and the empty antibonding MO 3eg(σ*) for the octahedral complexes have been observed in the Cl K edge, Ru LIII edge, and Rh LIII edge regions. It is found that the two absorption peaks at the Ru LIII edge reflect the ligand-field effect. An interpretation for experimental results of the Cl K edge and the Ru LIII edge absorption spectra in K3RuCl6 on the basis of the MO scheme leads us to the conclusion that the white lines at the Cl K edge suffer from the effect of core hole.

No abstract

With a two-crystal vacuum spectrometer, the sulfur Kβ emission spectra in fluorescence are measured for a series of alkali, alkaline-earth and hydrated 3d transition-metal salts with the SO4 2- ion. In addition, the sulfur K absorption spectra in a series of hydrated 3d transition-metal sulfates are measured with a bent-quartz-crystal vacuum spectrograph. The measured Kβ emission and K absorption spectra are presented along with the sulfur K absorption spectra of alkali and alkaline-earth sulfates reported previously. It is shown that the Kβ emission and K absorption spectra of sulfur in alkali and alkaline-earth sulfates are influenced by the cations, while those of hydrated 3d transition-metal sulfates are little affected by the metal ions. The sulfur Kβ emission spectra and the sulfur K absorption spectra are interpreted in terms of the molecular orbitals of the SO4 2- ion.

The K absorption spectra of sulfur in FeS, FeS2 (pyrite), and Fe2S3 have been measured with a 50 cm bent-quartz-crystal vacuum spectrograph. The spectra of FeS and Fe2S3 are similar to each other but are fairly different from that of FeS2. The FeS2 spectrum is discussed in terms of two theoretical calculations: the energy band for FeS2 (pyrite) and the molecular orbital (MO) of the S22− ion. The spectra for FeS and Fe2S3 are explained by the application of Terakura’s theory and the first absorption band is attributed to the transitions to the empty antibonding states formed by the redistribution of the sulfur 3p bands under the influence of the iron 3d bands.

The KP emission spectra of sulfur in a-MnS, FeS, CoS, NiS, and CuS, and in two modifications (zinc-blende and wurtzite structures) of ZnS and CdS are obtained with a two-crystal spectrometer, The spectra of FeS, CoS, and NiS consist of a broad band and are alike. The spectra from the modifications of ZnS and CdS are similar to each other. The spectrum of CuS consists of two prominent peaks and it is discussed in relation to the sulfur KP emission spectra from a-sulfur and NiS. The KP emission bands of ZnS and CdS are comparatively narrow, while those of the other metal sulfides are very wide. Results are evaluated by comparing the KP emission spectra of these metal sulfides with the sulfur-K absorption spectra and with the energy-band structures.

No abstract

No abstract

The Fe K absorption-edge structures of the NiAs-type FeS and the pyrite-type FeS2 have been measured with a high-resolution two-crystal spectrometer. The K absorption edges consist of a step-like structure and are interpreted in terms of the energy-band structures for these sulfides. The presence of the absorption structure is much clearer in Fes2 than in FeS. This difference is attributed to the difference of the iron 3d states in FeS and FeS2 and the distortion of the octahedron [FeS6]10− in these sulfides. The Fe K absorption spectrum of FeS2 is compared with the sulfur K absorption spectrum reported previously and a good agreement is obtained between them.