Studies of small Fe-Sn clusters in an argon matrix

Abstract

The M\ossbauer effect in $^{119}\mathrm{Sn}$ and $^{57}\mathrm{Fe}$ was employed to study and characterize small clusters of ${\mathrm{Fe}}_{x}{\mathrm{Sn}}_{y}$ 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 $^{57}\mathrm{Fe}$ isomer shift, quadrupole splitting, linewidth, and relative intensities of the $^{57}\mathrm{Fe}$ and $^{119}\mathrm{Sn}$ lines. Apart from the monomers and dimers of Fe and Sn, the following species were characterized: FeSn, ${\mathrm{Fe}}_{2}$Sn, Fe${\mathrm{Sn}}_{2}$, SnFeSn, and ${\mathrm{Fe}}_{3}$. 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\char22{}Sn bond is discussed in terms of the $^{57}\mathrm{Fe}$ hyperfine constants.