A real time contamination of the Ru surface and corresponding effect on its work function were studied using extreme ultraviolet photoelectron spectroscopy with a 13.5-nm wavelength of light. The change in work function indicates formation of molecular dipoles, oriented outward from the Ru surface. X-ray photoelectron spectroscopy investigations suggest variation in electromagnetic interaction with the components of the adsorbed foreign species when the emission angle from the target surface was changed from 0° to 50°; H 2O and C-O n show a strong coupling at lower angles and OH dominates at higher angles, whereas carbon is found in the mid-range peaking at 30°. © 2012 American Institute of Physics.