ELECTRONIC ABSORPTION-SPECTROSCOPY OF MATRIX-ISOLATED POLYCYCLIC AROMATIC HYDROCARBON CATIONS .1. THE NAPHTHALENE CATION (C10H8+)

The ultraviolet, visible, and near infrared absorption spectra of naphthalene (C10H8) and its radical ion (C10H8+), formed by vacuum ultraviolet irradiation, were measured in argon and neon matrices at 4.2 K. The associated vibronic band systems and their spectroscopic assignments are discussed together with the physical and chemical conditions governing ion production in the solid phase. The absorption coefficients were calculated for the ion and found lower than previous values, presumably due to the low polarizability of the neon matrix. This study presents the first spectroscopic data for naphthalene trapped in a neon matrix, where the perturbation of the isolated by its environment is minimum; a condition crucial to astrophysical applications.