Infra-Red Absorption Spectra of the Oxides of Chlorine

Abstract

WE have recently completed an examination of the infra-red absorption spectra of the monoxide and dioxide of chlorine. The unstable nature of these substances demanded the use of a monochromator method: this has the additional advantage of an increased purity of spectrum, but even under these conditions there is a considerable amount of scattered radiation in the region of longer wave-lengths. We have endeavoured to take advantage of the alteration in the chromatic foci of rocksalt to stop out most of the scattered light, but owing to the lack of transparency of this substance beyond 18μ (the optical train included rocksalt lenses and plates for the absorption cells and thermopile case), we obtained no measurable deflections on the galvanometer. The provision of optical parts of potassium bromide should eventually solve this difficulty. The observed bands for ClO₂ are recorded in the accompanying Table.