The infrared matrix isolation spectra of carbon dioxide. I. Deuterium matrices : Identification of bands due to carbon dioxide dimers

Abstract

The infrared spectra of CO2 isolated in deuterium matrices at c.6K are reported for molar ratios of D2/CO2 between 50 and 3200. The bending mode V2 of CO2 appears as a narrow doublet in the matrix spectra. Bands due to CO2 dimers are identified in the V2 region from their concentration dependence and from mixed isotope spectra (12CO2and 13CO2). No dimer bands were observed in the monomer antisymmetric stretching region. In this respect the spectra of CO2 in D2 matrices resemble those in N2 matrices. The observed dimer spectrum is compared with those predicted on the basis of T-shaped and staggered parallel configurations for the dimer and is interpreted as favouring the latter configuration. The desirability of obtaining matrix spectra at sufficiently high resolution is stressed.