Thermal-emission spectra of coagulated small MgO crystals

Abstract
The thermal-emission spectra of small MgO cubes (about 0.1 μm) were measured in the frequency region of their surface phonon modes. From the partial derivative of emissivity with respect to particle density, the emissivity of an MgO coagulation has been determined as a function of frequency. With an assumption of spherical coagulation, it is concluded that the dielectric function of small MgO particles and its temperature dependence are nearly the same as those of a bulk crystal.