Vapor absorption spectra of benzoxazole, benzimidazole, and benzothiazole near 2850 Å

Abstract

Sharp vapor absorption spectra, with origins at the frequencies listed, have been observed for benzoxazole (36 493 cm −1 ), benzimidazole (36 023 cm −1 ), and benzothiazole (34 327 cm −1 ). In each case the origin is the strongest band, and excited state fundamentals of approximately 700, 950, and 1225 cm −1 are prominent. The vibrational structure is similar to that of related heterocyclic compounds and some substituted benzenes. There is no evidence of a (π*–n) transition.