The observation of the high-resolution infrared spectrum of SH +3

Abstract

The v 3 fundamental band of SH + 3 has been observed in absorption in a hollow cathode discharge with a difference frequency laser system. The molecular constants of the ground state have been determined through a fit of the ground-state combination differences (from the observed transition frequencies). The band is perturbed and a preliminary analysis is made to obtain the molecular constants for the excited state. The lowest rotational transition frequency useful for astrophysical searches is predicted to be 293464(3) MHz.