INFRARED OPTICAL-PROPERTIES OF SOLID MONOMETHYL HYDRAZINE, N2O4, AND N2H4 AT CRYOGENIC TEMPERATURES

To account for and identify the effects of cryocontamination, the infrared complex refractive-index values of cryofilms of monomethyl hydrazine (MMH), hydrazine (H//2H//4), and nitrogen tetroxide (N//2O//4) were determined for the 500-3700-cm** minus **1 wave-number range. Thin MMH, N//2O//4, and N//2H//4 films from 0. 25 to 9. 0 mu m thick were formed on a germanium substrate at 20 and 80 K in vacuum, and the infrared transmittances were measured by using a Fourier-transform spectrometer. Values of the optical properties (n,k) were derived from the experimental transmittance data by using a nonlinear least-squares method with a thin-film-transmittance analytical model. These optical constants were compared with results obtained with the subtractive Kramers-Kronig technique. These optical properties are important for predicting the performance of contaminated optical components.