摘要
High-resolution Cs 4d core-level spectra were performed by photoemission spectroscopy at photon energies hν=108-115 eV. At room temperature, for submonolayer metal deposition on a Ge(100) surface, a nonstatistical branching ratio Cs 4(Formula presented):4(Formula presented) was obtained. Its value was found close to 4/3 instead of the usual 3/2. Conversely, Cs 4d spectra performed on a thick metal layer presented two components, the first due to the surface and the other to the bulk; in this case, only the surface component was affected by a nonstatistical spin-orbit ratio. A possible explanation of this effect is discussed with reference to the relativistic random-phase approximation accounting for a similar effect in Xe. © 1996 The American Physical Society.