Absorption spectra in the vacuum ultraviolet and the ionization potentials of naphthalene and naphthalene-d8 molecules

Abstract

The vapour absorption spectra of naphthalene and naphthalene-d8 were obtained photographically and photoelectrically from 50000 to 70000 cm-1. A series of Rydberg transitions and possibly two π*-π systems are observed. Each of the five Rydberg series converges to an ionization potential of 65620 � 40 cm-l, i.e. 8.136 � 0.005 eV (C10H8), and 65640 � 60 cm-l, i.e. 8.138 � 0.008 eV (C10D8). The quantum defects of the series are (0.94, 0.88, 0.82, 0.67, 0.53) � 0.01. The significance of these results is discussed.