Mass-analyzed threshold ionization spectroscopy of trans-1-methoxynaphthalene cation and the methoxyl substitution effect

► The MATI spectra of 1-methoxynaphthalene have been recorded. ► The adiabatic ionization energy has been determined to be 61357 cm−1. ► Most of the observed cation vibrations result from the in-plane ring vibrations. ► The methoxyl substitution can affect transition energy and molecular vibrations.