Direct evidence for occupied Cs 6s states in CsC8

Abstract The 6s density of states at cesium sites in the CsC 8 graphite intercalation compound has been probed by soft x-ray emission spectroscopy. An analysis of the 6 s → 2 p 3 2 transition shows that Cs 6s states are present below the Fermi energy. The result is discussed in relation to other experiments which had so far been taken to indicate complete charge transfer towards graphite layers and compared to similar recent measurements performed on KC 8 which indicate the presence of potassium 4p states strongly hybridized with the graphite π bands.