Absorption Spectra of 3-4 Benzpyrene

Abstract

EVIDENCE has been given¹ that benzpyrene emits various fluorescence spectra according to its physical state. Molecular benzpyrene, the monoclinic, the orthorhombic crystallized modification and the colloidal suspension in water fluoresce violet, green, blue and yellow respectively. The fluorescence spectrum of dissolved benzpyrene is unchanged in various solvents except for slight displacements of the entire group of bands². We have now studied the absorption spectra with a low-voltage projection lamp as a light source for a continuous spectrum, which restricted the observation to the radiation transmitted by glass. It was found that the first broad absorption band of dissolved benzpyrene³ has three components, α, Î, Î, at 383, 380 and 377 mµ respectively in hexane (Fig. 1,a). They are of almost the same strength, but they behave differently in various solvents. While the α-component persists as the maximum, Î and Î fuse and disappear more or less by polar effects due to the solvent.