Optical constants in the infrared for K_2SO_4, NH_4H_2PO_4, and H_2SO_4 in water*

Relative, specular reflectances of individual 0.5M aqueous solutions of K2SO4 and NH4H2PO4 and of 3M H2SO4 were measured in the 2-20-μm region of the infrared for polarized radiant flux having the electric field vector perpendicular to the plane of incidence. Distilled water was the reflectance standard. The angle of incidence was 70.03° ± 0.23°. Kramers–Kronig analysis of the relative reflectance spectra provided phase-difference spectra for the aqueous solutions and a tabulation of spectral values relative to air for the index of refraction and extinction coefficient. The strengths of selected infrared bands of the solutes were determined by integrating values for the molecular extinction coefficients over the spectral regions of the bands.