Calculation of Infrared Mass Extinction Coefficients of Graphite Spheres and the Effects of Diesel Oil Coating

Liquid and solid obscurants are widely used in the modern battlefield to attenuate visible and infrared radiation. Since they are sometimes used simultaneously, the solid particles may be wrapped by the liquid. In this paper we investigated into the infrared extinction characteristics of the graphite spheres with and without the diesel oil coating. Mie’s theory and the theory of extinction by two-layered sphere were employed in the calculation of the spectral mass extinction coefficients (SMECs). The relationships between SMECs of particles and their sizes were examined. The maximal SMECs of these two types of particles at several wavelengths were also obtained.