Electron-spectroscopy study of LiC60: Charge transfer and dimer formation

Li-C-60 compounds LixC60 were studied for average Li concentration (x) over bar less than or equal to 1 using photoelectron spectroscopy. Strong evide nce is found for the formation of LiC60 dimers, as well as a second phase. The study suggests that the smallest alkali-metal Li bonds to C-60 largely ionically for certain configurations. An investigation of the Li 1s level s hows that under certain conditions the energetics favor a backdonation of t he transferred electron to the Li ion.