The C is photoemission lineshape and width has been studied for methoxy (CH//3O), formate (HCO//2) and CO on Cu(100). The authors find the Doniach-Sunjic asymmetry of the lineshape to be different for the three adsorbates and correlates these differences with the adsorption geometry. The observed shakeup satellites exhibit a greatly increased width compared to the main lines, which is attributed to the reduced lifetime of the excited state of the C 1s core hole.