IN THE ACENE SERB : benzene, naphthalene, anthracene, tetracene and pentacene the ratio of the wavelength of the p-bands to the B-bands is continuously increased from 1.138 to 1.289, 1489 and 1.915 resp. This causes profound changes in the spectra. Thus the a-bands disappear in the anthracene spectrum behind the more intense p-bands and reappear again in the minimum of the pentacene spectrum. No such changes are observed if one linear ...