VAPOR ABSORPTION SPECTRA AND OSCILLATOR STRENGTHS OF NAPHTHALENE, ANTHRACENE, AND PYRENE

Abstract

Vapor absorption spectra have been measured for naphthalene, anthracene, and pyrene using a modified Beckman DU Spectrometer. Vapor concentrations were determined using published vapor pressure data, and oscillator strengths were computed for a total of five transitions in the three molecules. It was found that the vapor oscillator strengths are considerably lower than in solution by a factor greater than that predicted by classical theory. An absorption region at about 41,000 cm. −1 in anthracene is tentatively assigned as the 1 B 2u + state calculated by Pariser to lie at 42,400 cm. −1 .