CH STRETCHING OVERTONE SPECTRA AND INTENSITIES OF VAPOR-PHASE NAPHTHALENE

Room temperature vapor phase CH stretching overtone spectra of naphthalene are reported for the first time. The vibrational overtone spectra of naphthalene are recorded in the Delta v(CH) = 2 and 3 regions by conventional near-infrared spectroscopy and in the Delta V-CH = 4 and 5 regions by intracavity titanium:sapphire laser photoacoustic spectroscopy. Absolute oscillator strengths are obtained from the conventional spectra. The photoacoustic spectra provide relative oscillator strengths between the observed peaks within a given overtone. Peaks corresponding to two nonequivalent CH stretching local modes are consistently assigned. Oscillator strengths are calculated with an anharmonic oscillator local mode model and ab initio dipole moment functions. We compare the calculated and experimental oscillator strengths. Our simple calculations, which contain no adjustable parameters, are in very good agreement with the observed intensities.