Mössbauer Effect at High Pressure forFe57in Titanium, Vanadium, and Copper

We have measured the effect of pressure to 250 kbar on the isomer shift of ${\mathrm{Fe}}^{57}$ in dilute solution in titanium, vanadium, and copper. These results and previously published data on ${\mathrm{Fe}}^{57}$ in iron indicate that for the bcc metals of the first transition-metal series, the $4s$-electron density scales approximately with bulk density. For more closely packed phases the $s$-electron density changes less rapidly than the bulk density.