An infrared study of the forbidden symmetric stretching mode of carbon disulphide in binary mixtures with iodine

Abstract

A detailed study has been made of the 'excess' induced nu band of CS in binary mixtures with iodine. A simple model based on the pair molecular interaction via an electrostatic quadrupole-dipole induction mechanism results in a very pleasing interpretation of the observed (very weak) band profile. There is no need to invoke the involvement of donor-acceptor interactions. The agreement between observed and calculated widths (using known correlation times and diffusion coefficients of the individual components) is found to be extremely good. The main conclusion is that both hindered rotational motion of the CS₂ molecule and the relative two-body translational dynamics contribute to the observed bandwidth. This conclusion is in good agreement with that made from a far-infrared study of the v(I-I) mode of the same system.