Van der Waals complexes composed of naphthalene and triethylamine have been studied in free jet expansions by fluorescence excitation and resonance-enhanced two-photon ionization techniques. Intermolecular vibrational bands with frequencies of 8 and 40 cm-1 appear to promote exciplex formation. The rates of exciplex formation have been measured as a function of excitation energy. The exciplex formation is found to be vibrational state dependent and to be enhanced above 432 cm-1.
