Mass analyzed threshold ionization spectroscopy of the 35Cl and 37Cl isotopomers of p-chlorophenol and isotope effect

The band origins of the S1 ← S0 electronic transition and the ionization energies of 35Cl and 37Cl isotopomers of p-chlorophenol are found to be the same, with the values of 34 813 ± 2 and 68 104 ± 5 cm−1, respectively. Although the general spectral features of these two isotopomers are similar, frequencies of some vibrational modes are slightly different by a few wavenumbers. This frequency shift somewhat depends on the degree of the Cl atom involved in the molecular motion.