Energetics and fragmentation of single-doped tin and lead clusters

Abstract

The fragmentation behavior of the bimetallic cluster ions ${\text{Sn}}_{N}{\text{Pb}}^{+}$ and ${\text{Pb}}_{N}{\text{Sn}}^{+}$ has been investigated by tandem time-of-flight mass spectrometry in combination with density-functional theory. The low-energy surface-induced dissociation patterns of ${\text{Sn}}_{N}{\text{Pb}}^{+}$ and ${\text{Pb}}_{N}{\text{Sn}}^{+}$ with $N=6--11$ are dominated by the subsequent loss of atoms. For ${\text{Sn}}_{N}{\text{Pb}}^{+}$ first the single lead atom is split off; in contrast the ${\text{Pb}}_{N}{\text{Sn}}^{+}$ clusters dissociate mainly in fragments retaining the single tin atom, which is in full accordance with the quantum chemical results. For larger collision energies the complete set of smaller tin fragment ions ${\text{Sn}}_{N\ensuremath{-}M}^{+}$ with $M<N$ is found for ${\text{Sn}}_{N}{\text{Pb}}^{+}$, whereas the ${\text{Pb}}_{N}{\text{Sn}}^{+}$ clusters decay into two series of ${\text{Pb}}_{N\ensuremath{-}M}{\text{Sn}}^{+}$ and ${\text{Pb}}_{N\ensuremath{-}M}^{+}$ fragments with $M<N$.