Crystal fluorescence of carcinogens and related organic compounds

The crystalline fluorescence spectra of 41 organic compounds, including 29 known carcinogens, have been observed, when excited by 254 mμ radiation. For anthracene, 1:2-benzanthracene and other compounds, a correction has been made for self-absorption, and the molecular fluorescence spectra have been derived. In the 1:2-benzanthracene derivatives, a sequence of spectral types is observed, ranging from type A, with a vibrational structure similar to the spectrum of the parent compound, to type E, with a single broad, diffuse band and a major bathochromic shift. The effect is attributed to molecular interaction in the crystal. The molecular photofluorescence decay times of 32 of the compounds are reported.