The temperature dependent effect of adsorbate hindered vibrations on NEXAFS analyses: NO on Pd{110}

Abstract The importance of the effect of adsorbate frustrated translational motion on NEXAFS analyses is presented and its temperature dependence is discussed in terms of a harmonic potential model. NO on Pd{110} is studied to show the effect of the frustrated vibration on the determined orientation. The harmonic model agrees with the observed temperature dependence of the NEXAFS data at very low temperatures. In the range above 50 K the results indicate an anharmonic potential, leading the frustrated vibrational mode into a diffusive hopping motion across the surface, at sufficiently high temperatures.