Isomer shift in BaSnO$_3$ under a pressure up to 15 GPa

The dependence of the unit cell volume of BaSnO$_3$ on the pressure up to 15 GPa has been investigated and the constants of the Murnaghan equation of state B$_0$ = 178.39 $\pm$ 4.09 GPa and B$_0'$ = 4.68 $\pm$ 0.56 have been obtained using the X-ray diffraction method. The change of the isomer shift (IS) in BaSnO$_3$ with a variation in the pressure $P$ has been examined using the gamma resonance method. This quantity is $\partial$IS$(P)$/$\partial P$ = -(0.00474 $\pm$ 0.0002) mm s$^{-1}$ GPa$^{-1}$ or, taking into account the measurements of the unit cell parameter under pressure, $\partial$IS/$\partial L$ = 1.42 mm s$^{-1}$ $\mathring{\mathrm{A}}^{-1}$, where $L$ is the tin-oxygen distance.