LI K SPECTRA OF LI/BE(0001)

We present Li 1s core photoemission and absorption spectra as a function of overlayer density for Li/Be(0001). The combination of these spectroscopies allows us to clearly identify atomic-like and substrate-derived features in the absorption spectra, which reflect the unoccupied levels of the core-excited final state. Both types of spectra also reflect the change in the electronic screening associated with the formation of an occupied overlayer band in the initial state. These measurements thus clearly indicate significant influence of the chemical environment on core excitation dynamics of metal adlayers on metal substrates.