Abstract

Using a supersonic expansion of helium and sulfur dioxide excited by a corona discharge, we have observed spectra of the A–X band system of the thionyl ion, SO⁺, in emission between 255 and 450 nm. The spectra are rotationally and spin-orbit cooled by the expansion, allowing features which ordinarily are highly congested to be analyzed rotationally. The derived constants have been merged with those obtained from previously published spectra of SO⁺, as well as from new analyses of unpublished high resolution measurements. The formation of the excited thionyl ion occurs via a dissociative charge transfer reaction between He⁺ and SO², and its primary path of destruction appears to be reactions with excess sulfur dioxide. Derived constants for the A–X system of the thionyl ion have been obtained for v″ = 0–10 and v' = 0–11. These new data substantially extend the range of vibrational and rotational information available for this ion and are expected to simplify future searches at higher resolution.

© 1986 Optical Society of America