Fluoride Interference Films on Uranium Dioxide. I. The Kinetically Derived Optical Equation

Abstract

At the interfaces of absorbing dielectrics reflected light undergoes an abrupt phase change other than zero or π. For a transparent interference film on an absorbing dielectric substrate this change has the effect of shifting the wavelength of maximum interference toward a higher value. From the spectrophotometrically determined rates of film formation an extrapolation to zero time (zero thickness) gives the fractional wavelength shifts directly. Values are obtained experimentally for the hydrofluorination reaction of uranium dioxide and are compared with values calculated from optical theory.