Fig. 2
From: Oxidative reactivity of alkali-like superatoms of group 5 metal-encapsulating Si16 cage nanoclusters
XPS spectra for M@Si16 superatom deposited on a C60 substrate. The binding energies are around core levels of Si 2p for a V@Si16, b Nb@Si16, and c Ta@Si16, and metal core levels of d V 2p for V@Si16, e Nb 3d for Nb@Si16, and f Ta 4 f for Ta@Si16. Reference binding energies of Si 2p3/2 for bulk Si (Si0), and M (V 2p2/3, Nb 3d5/2, and Ta 4f7/2) for M0 and M2+ are marked by vertical bars. Their binding energies show zerovalent Si and monovalent M+
