ISOMER SHIFTS OF 90-KEV GAMMA-RAYS OF 99RU IN RUTHENIUM COMPOUNDS

The recoilless nuclear resonance absorption of the 90 keV γ-rays of99Ru was observed in a variety of chemical compounds of ruthenium in the oxidation states +2 through +8 at 4.2 ° K. For most of the compounds isomer shifts increasing monotonically with the oxidation state of ruthenium were found. This behaviour, which may essentially be attributed to the decreasing number of 4 d electrons, and the few exceptions from it are discussed qualitatively on the basis of the molecular orbital theory. © 1969 Springer-Verlag.