Alkali metal adsorption on Ru(001)

The adsorption of Na, K and Cs on Ru(001) was studied by thermal desorption (TD), work function (WF) measurements, and electron energy loss spectroscopy (EELS). The coverage dependences of the desorption energy, E d () and the mean dipole moment 2 μ-() were found to be similar for all alkali metals under investigation. Therefore, the dipole depolarization interactions determined the slope of the E d() curves. These interactions also determined the energy changes of the Na 2p, K 3p and Cs 5p core level excitations with increasing . The one-electron transitions involving alkali valence orbitals and the appearance of plasmon excitations in the alkali overlayer are also discussed.