  Face-centered cubic (FCC) is an important crystal structure, and there are
ten elemental FCC metals (Al, Ag, Au, Ca, Cu, Pb, Pd, Pt, Rh, and Sr) that have
this structure. Three of them could be used as photocathodes (Au, Rh, Pt, and
Pd have very high work functions; Ca and Sr are very reactive). Au has high
work function, but it is included for the sake of the completeness of noble
metals' photoemission investigation. In this paper, we will apply the
nonparametric photoemission model to investigate these four remaining FCC
photocathodes; two noble metals (Cu and Au), two p-block metals (Al and Pb).
Apart from the fact that the direct photoemission is dominant for most FCC
photocathodes, photoemission from a surface state has also been observed for
the (111)-face of noble metals. The optical properties of the (111) surface
state will be extensively reviewed both experimentally and theoretically, and a
surface state DFT evaluation will be performed to show that the photocathode
generated hollow cone illumination (HCI) can be realized.
