Dopant dependent stability of Co n TM+ (TM = Ti,V, Cr,and Mn) clusters

In this paper, we present a photofragmentation study of mass-selected transition metal-doped cobalt cluster cations Co _n TM⁺  (n = 8–18, TM = Ti, V, Cr, and Mn). Time-of-flight spectra recorded after laser excitation of mass-selected clusters in the gas phase show that the evaporation of a cobalt atom is the most facile dissociation channel for clusters with TM = Ti and V, suggesting an enhanced stability of the doped clusters compared to the bare ones. In contrast, for Co _n TM⁺ with TM = Cr and Mn, the loss of the dopant atom is found to be the preferred dissociation channel. Co₁₃Cr⁺ is a notable exception and favors dissociation by loss of a neutral Co atom. It is implied that substituting Mn and Cr generally destabilizes the cobalt clusters with the exception of Co₁₂Cr⁺, which is relatively more stable than Co ₁₃ ⁺ . Additional measurements of V _n Co⁺ (n = 9–16) show that the loss of a Co atom is still the most facile dissociation channel, which is in agreement with the predicted stronger V?V bond compared to the V?Co one.