The effect of herbicides, pesticides, and fertilizers on the optical properties of water
Abstract
A reflectometer accessory for a spectrophotometer was designed and constructed in our laboratory. Using distilled water as the reflectance standard, the reflectometer was used to measure relative specular reflectance of 0.5M aqueous solutions of K2SO4 and NH4H2PO4 in the 2-12m wavelength region and for 1M (NH2)2CO in the 2-20m wavelength region for infrared radiant flux incident at about 70 degrees and linearly polarized perpendicular to the plane of incidence. Absolute reflectances of the solutions were computed for 70 degrees angle of incidence by using the relative reflectance measurements, one of the Fresnel equations, and the optical constants of water. The optical constants of the aqueous solutions were then computed by applying a Kramers-Kronig phase-shift dispersion analysis to the absolute reflectance spectra. The report provides a description of the instrumentation and the experimental procedures for making the measurements. The relative reflectances, absolute reflectances, and optical constants are presented in graphical form in the text and are tabulated in Appendix I. Spectral signatures characteristic of the solutes are discussed in the text. In addition, further investigations of the optical constants of distilled water were made in that they are related to the investigations of aqueous solutions. The work on distilled water was accomplished in cooperation with Dr. Dudley Williams at Kansas State University. A reprint describing the work is presented in Appendix I.