Resonant two-photon mass-analyzed threshold ionization spectroscopy of 1-fluoronaphthalene and 2-fluoronaphthalene

► We report the 2C-R2PI and MATI spectra of 1- and 2-fluoronaphthalenes. ► Frequencies of cation vibrations are higher than those of neutral in S1 state. ► Geometry and normal vibrations of cation resemble those of neutral in S1 state.