The x-ray-photoelectron core-level linewidths show pronounced differences between atomic C, N, and O adsorbed on Ni(100). Furthermore, the widths are temperature dependent. The observed effects are reproduced within a model based on the creation of vibrational excitations in the core-ionization process. This explains the large linewidths observed for many adsorbate systems. The results have important consequences for the general understanding of line shapes in core-level spectroscopies.

• Received 22 May 1989

DOI:https://doi.org/10.1103/PhysRevLett.63.1483