Calibration of the isomer shift and measurement ofΔRRfor the 13-keV Mössbauer transition ofGe73

Abstract

The first isomer shifts of the 13-keV $^{73}\mathrm{Ge}$ M\"ossbauer transition are reported. Shifts are observed in Cu and in GaAs. The shift of Ge in GaAs versus Ge is interpreted in terms of a calculation by Pickett et al. of the bonding at a (110) Ge-GaAs interface. From this and a calculation by Nestor et al. of electron density at the $^{73}\mathrm{Ge}$ nucleus we measure $\frac{\ensuremath{\Delta}R}{R}=+0.45(2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. Shell-model calculations of the nuclear size change by Uher predict $\frac{\ensuremath{\Delta}R}{R}=+0.50\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. The Ge:Cu shift indicates $s$-electron transfer from Cu to substitutional Ge.