Infrared Spectrum and Dipole—Dipole Coupling in Crystalline Cyanogen

Abstract

The infrared spectrum of a polycrystalline film of cyanogen at 80°K is reported for the region from 4000 to 500 cm⁻¹. In an attempt to account for the splitting observed for the ν₃ fundamental, transition‐dipole—transition‐dipole interactions have been calculated by computing lattice sums for a variety of crystal shapes and sizes. It is concluded that dipole—dipole coupling can account for only a fraction of the observed splitting.