Cation spectroscopy of o-fluoroanisole and p-fluoroanisole by two-color resonant two-photon mass-analyzed threshold ionization

► The cation spectra of o-fluoroanisole and p-fluoroanisole have been recorded. ► The ionization energies of these two isomers are precisely determined. ► Most of the active cation vibrations are in-plane ring motions. ► Relative location of substituents can influence molecular properties.