Nuclear forward scattering by the 68.7 keV state of 73Ge in CaGeO3 and GeO2

We measured nuclear forward scattering of synchrotron radiation by the 68.7 keV nuclear resonance of 73Ge with a half-life . The Debye temperatures of CaGeO3 in the wollastonite, garnet and perovskite phases were determined to be 386(20) K, 437(20) K and 507(20) K, respectively, and 309(20) K and 459(11) K for GeO2 in the quartz and rutile phases, respectively. The isomer shift is clearly dependent on the Ge valence but not directly on the coordination geometry. The so far unknown magnetic moment μe of the 68.7 keV excited state of 73Ge is determined to be . Time domain 73Ge Mossbauer spectroscopy with the 68.7 keV resonance is feasible for isomer shift and Debye temperature measurements but so far neither electric quadrupole nor magnetic hyperfine interactions could be observed.