Carbon 1s photoelectron spectroscopy of the chlorinated methanes: Lifetimes and accurate vibrational lineshape models

► The theoretical challenges in accurately computing the CCl bond contraction accompanying carbon 1s ionization in chlorinated hydrocarbons have been mapped out. ► Accurate vibrational lineshape models have been prepared for carbon 1s ionization of CH4−nCln, n = 1-4. More approximate schemes for application to larger molecules are proposed. ► Accurate C1s-hole lifetimes have been determined in fits to the experimental X-ray photoelectron spectrum for each of the chlorinated methanes. ► The resulting values for the lifetime broadening are 88 ± 5 meV for CH3Cl, 80 ± 5 meV for CH2cl2, 74 ± 5 meV for CHCl3 and 62 ± 5 meV for CCL4.