Element-selective vertical height determination for an organic monolayer by a scanned-energy photoelectron-yield soft x-ray standing wave technique

A photoelectron-yield soft x-ray standing wave (SW) technique with the scanned-energy mode has been applied to the vertical height determination of the atoms of specific elements involved in an organic monolayer prepared by the Langmuir-Blodgett method on a WC superlattice substrate (d=30.9 Å) that serves as a SW generator. The vertical positions of two different-element atoms were determined from the SW profiles. This kind of information is complementary to the molecular-orientation estimation by the polarized x-ray absorption spectroscopy and the combination of these techniques will be a powerful tool to understand the structures of organic monolayers.