Studies of small Fe-Sn clusters in an argon matrix

The Mössbauer effect in Sn119 and Fe57 was employed to study and characterize small clusters of FexSny formed and stabilized in a solid argon matrix. Various low concentrations of Fe and Sn atoms in Ar were used (0.1-0.5 at.%), resulting in formation of dimers and trimers. The constituents and geometrical structures were confirmed by self-consistent assignment of the Fe57 isomer shift, quadrupole splitting, linewidth, and relative intensities of the Fe57 and Sn119 lines. Apart from the monomers and dimers of Fe and Sn, the following species were characterized: FeSn, Fe2Sn, FeSn2, SnFeSn, and Fe3. Conclusions were drawn regarding the reactivity of Fe and Sn atoms and dimers in the matrix preceding solidification of argon. The nature of the Fe-Sn bond is discussed in terms of the Fe57 hyperfine constants.