  X-ray standing wave (XSW) excited photoelectron emission was used to measure
the site-specific valence band (VB) for 1/2 monolayer (ML) Pt grown on a SrTiO3
(001) surface. The XSW induced modulations in the core level (CL) and VB
photoemission from the surface and substrate atoms were monitored for three hkl
substrate Bragg reflections. The XSW CL analysis shows the Pt to have an
fcc-like cube-on-cube epitaxy with the substrate. The XSW VB information
compares well to a density functional theory calculated projected density of
states from the surface and substrate atoms. Overall, this work represents a
novel method for determining the contribution to the density of states by
valence electrons from specific atomic surface sites.
