An analytical formula applicable to Fourier transformation (FT) of normal photoelectron diffraction (NPD) is derived. The formula indicates that multiple perpendicular distances from the overlayer to substrate layers within the electron mean free path can be extracted by Fourier transformation. A simple dependence of the NPD on the initial (core) level given by ${\mathrm{}(-1\mathrm{})\mathrm{}}^{l_i+1\mathrm{}}$ is derived. Examples of chalcogens on Ni(001) and Ni(111) demonstrate the use of FT to an accuracy of 0.026 Å.

• Received 2 September 1981

DOI:https://doi.org/10.1103/PhysRevB.25.6526