EELS cross-section of surface phonons on Ag(001)

We present EELS cross-section data of surface phonons on Ag(001) along GAMMABAR-MBAR. The inelastic intensity is due to the contribution of different modes which are not solved by the EEL spectrometer. However, the shape of the inelastic intensity shows a strong dependence on impact energy for all wave vectors, which allows tuning the EELS on the different modes. The dependence of the loss frequency on impact energy is at variance with the one reported previously for MBAR, leading to the conclusion that other modes contribute to the inelastic intensity besides S1 and L1 which dominate at MBAR