The data presented here consists of library spectra obtained for use with a laser absorption spectroscopy gas sensor. The spectra include absorbance data for SO2, SO3, H2O and H2SO4 at 300° C and 350° C temperatures in two wavelength bands, 7-8 µm and 8-9 µm. Datasets were collected in a heated multi-pass absorption Herriott cell using two tunable external cavity quantum cascade laser sources, with the resulting transmission signal measured using a thermoelectrically cooled MCT detector. The absorbance was calculated from measurements taken with and without gas samples and scaled for the length of the multi-pass cell. The data will be useful for scientists and engineers building SO3 and H2SO4 gas sensing equipment for emission monitoring, process control, and other applications.
