Hyperfine Interactions ofSn119Atoms in Rare-Gas Matrices at 4.2 K

The isomer shift (IS) analysis of the observed Mössbauer resonance in ${}_{}{}^{119}{}_{}{}^{}\mathrm{Sn}$ atoms isolated in rare-gas matrices at 4.2 K gives $\frac{\delta R}{R}=7.3\mathrm{}\times {10}^{-5\mathrm{}}$ for the 23.9-keV $\gamma$ transition. A comparison of the IS data in tin compounds with that of the rare-gas-matrix-isolated ${}_{}{}^{119}{}_{}{}^{}\mathrm{Sn}$ atom suggests that the electron densities at the tin nucleus in tin compounds are a "solid-state factor" $D_s=1.25\mathrm{}$ higher than the electron densities in the corresponding free-ion configurations. A pair of additional Mössbauer resonances appears at higher concentrations of tin in rare-gas matrices. These lines are interpreted as the result of the quadrupole splitting of the $I=\frac{3}{2}$ excited state of ${}_{}{}^{119}{}_{}{}^{}\mathrm{Sn}$ in the axial-symmetric electric field gradient produced by a nearest-neighbor tin atom (tin dimer). The observed quadrupole splitting is $E_Q=3.5\mathrm{}\pm 0.25$ mm/sec.