The multiple-scattering cluster method has been employed to calculate the chlorine 1s near edge X-ray absorption fine structure (NEXAFS) of the Cl-passivated Ge(1 1 1) surface. The physical origins of the resonances in NEXAFS have been unveiled. It is shown that the most important resonance is attributed to the photoelectron scattering between the central chlorine and the top most germanium atom which is just below the core excited chlorine. Our studies confirm the atop Cl-Ge monochloride structure and show that the Cl-Ge bond length is equal to 2.15 ± 0.05 Å, in good agreement with the previous extended X-ray absorption fine structure results and ab initio calculations.
- Near edge extended X-ray absorption fine structure (NEXAFS)