Mössbauer lattice temperature of tetragonal (P4nmm) SnO

The lattice-dynamical properties of tetragonal (black) SnO (with space-group symmetry $\frac{P4\mathrm{}}{\mathrm{nmm}}$) have been examined over the temperature range $78\le T\le 300$ K by variable-temperature ${}_{}{}^{119}{}_{}{}^{}\mathrm{Sn}$ Mössbauer-effect measurements. The lattice temperature calculated from the temperature dependence of the recoil-free fraction (assuming the atomic mass) is 229 K. Using the effective vibrating mass calculated from the temperature dependence of the isomer shift ($M_{\mathrm{eff}}=169\mathrm{}$ g ${\mathrm{mol}}^{-1\mathrm{}}$) leads to a lattice temperature of 193 K. The quadrupole-coupling hyperfine parameter is only weakly temperature dependent over the above temperature range, and there is no evidence of a vibrational anisotropy parallel and perpendicular to the fourfold rotational axis through the metal atom. The recoil-free fraction at 295 K is 0.35±0.02.