Infrared optical constants of aqueous solutions of sodium sulfate

The optical constants n(ν) and k(ν) for 1.0- and 0.5-M concentrations of sodium sulfate at ambient temperatures were determined by Kramers–Kronig phase-shift analyses of the near-normal reflectances over the spectral region from 2 to 20 μm. For the absorption that is due to the ν3 vibration of the SO42− ion, total band strengths, in reciprocal centimeters/(mol/liter), of 14.2 and 13.6 were measured for the 1.0- and 0.5-M concentrations, respectively. Changes in band position and intensity are discussed for this absorption.