Disentangling the complex line profiles in the Cl 2p photoelectron spectra of Cl2

High-resolution Cl (2p) photoelectron spectra of Cl2 are reported and their complex structure is analyzed in detail, taking into account molecular field (MF), spin–orbit (SO) and parity splitting. High-level ab initio calculations were performed to provide reliable values for spectroscopic parameters. Accurate data analysis enabled us to determine the value of molecular–field splitting of 86 ± 7 meV, and values of 92 ± 5, 79 ± 11 and 105 ± 12 meV for the lifetime line widths of the 2 Π 1 2 , 2 Σ 1 2 + and 2 Π 3 2 states, respectively. The gerade–ungerade splitting of less than 5 meV is obtained from the calculations.