We present a combined experimental and theoretical investigation of small neutral vanadium and manganese doped silicon clusters Si n X (n = 6−9, X = V, Mn). These species are studied by infrared multiple photon dissociation and mass spectrometry. Structural identification is achieved by comparison of the experimental data with computed infrared spectra of low-lying isomers using density functional theory at the B3P86/6-311+G(d) level. The assigned structures of the neutral vanadium and manganese doped silicon clusters are compared with their cationic counterparts. In general, the neutral and cationic Si n V0,+ and Si n Mn0,+ clusters have similar structures, although the position of the capping atoms depends for certain sizes on the charge state. The influence of the charge state on the electronic properties of the clusters is also investigated by analysis of the density of states, the shapes of the molecular orbitals, and NBO charge analysis of the dopant atom.
We gratefully acknowledge the support of the Stichting voor Fundamenteel Onderzoek der Materie (FOM) for providing beam time on FELIX. The authors thank the FELIX staff for their skillful assistance, in particular Dr. B. Redlich and Dr. A. F. G. van der Meer. P.C. thanks D. Aguilar for technical support, and the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT) for financial support. V.T.N. thanks the KU Leuven for a postdoctoral fellowship and J.T.L. thanks the Alexander von Humboldt Foundation for financial support. This work is supported by the Fund for Scientific Research-Flanders (FWO), by the Flemish Concerted Action (Contract No. GOA/2009/06), and by the Deutsche Forschungsgemeinschaft within FOR 1282 (FI 893/4-1).
I. INTRODUCTION II. EXPERIMENTAL AND THEORETICAL METHODS III. RESULTS AND DISCUSSION A. Infrared absorption spectra of Si n V (n = 6−9) 1. Si6V 2. Si7V 3. Si8V 4. Si9V B. Infrared absorption spectra of Si n Mn (n = 6, 8, and 9) 1. Si6Mn 2. Si8Mn 3. Si9Mn C. Influence of the charge state on the electronic structure of Si n V+,0 and Si n Mn+,0 IV. CONCLUSION