Photoionization and Absorption Coefficients of OCS

Abstract

Absolute absorption and photoionization coefficients of OCS gas have been measured in the 600–960-Å region using a 1-m Seya–Namioka-type scanning vacuum ultraviolet monochromator. The Hopfield helium continuum was used as a background source with photoelectric detection of the dispersed light. A number of peaks were observed in both the absorption and photoionization spectra at wavelengths that agree well with those of a high-resolution photographic spectrum. A series of the “apparent emission type” which converged at 17.931 eV had the Fano shape for a preionization process in both the absorption and ionization spectra. The total continuum underlying the band structure had been estimated, as well as that fraction due to ionization and to dissociation. Fluorescence emission was observed for all wavelengths of excitation in the Hopfield continuum. Peaks in the spectrum of the total fluorescence yield coincided in wavelength with absorption bands of Rydberg-type series converging to a limit at 16.04 eV. Maximum of the continuum underlying the fluorescence was at about 810 Å.