Studies of small Fe-Sn clusters in argon matrix (invited)

The Mössbauer effect in ¹¹⁹Sn and ⁵⁷Fe was employed to study and characterize small clusters of Fe_xSn _y formed and stabilized in a solid argon matrix. Various low concentrations of Fe and Sn atoms with respect to Ar were used (0.1-0.5 at. %), resulting in formation of dimers and trimers. The constituencies and geometrical structures were confirmed by self-consistent assignment of the ⁵⁷Fe isomer shift, quadrupole splitting, line width, and relative intensities of the ⁵⁷Fe and ¹¹⁹Sn lines. Apart from the the monomers and dimers of Fe and Sn the following species were characterized, namely: FeSn, Fe₂Sn, FeSn₂, SnFeSn, and Fe₃. Conclusions were derived regarding the reactivity of Fe and Sn atoms and dimers in the matrix preceding solidification of argon. The nature of Fe-Sn bond is discussed in terms of the ⁵⁷Fe hyperfine constants.