![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The spectra of polydiacetylene crystals may be categorized such that they form two distinct classes. There are the long wavelength reflectors with their peaks of reflectivity from 15,000 to 16,000 cm−1 and the short wavelength reflectors with their reflection peaks from 18,000 to 19,000 cm−1. In the former set where the crystals reflect a reddish-gold color, the vibrational structure is greatly enhanced compared to the spectra for the systems of the second class which reflect in the green. X-ray crystallographic determinations have shown that in the case of the gold-reflecting crystals the polymer may be represented by an acetylenic backbone: