Two professors at Tokai University chart optical properties from the vacuum ultraviolet region to the infrared region for 102 metal, semiconductor, and ionic crystal An ionic crystal is a crystal consisting of ions bound together by their electrostatic attraction. Examples of such crystals are the alkali halides, including potassium fluoride, potassium chloride, potassium bromide, potassium iodide, sodium fluoride, and other combinations of materials. Organized alphabetically, each entry summarizes the crystal system, natural production and artificial growth methods, and electrical properties before commenting on transmittance and reflectance spectra, optical constants, the dispersion relation In physics, the dispersion relation is the relation between the energy of a system and its corresponding momentum. For example, for massive particles in free space, the dispersion relation can easily be calculated from the definition of kinetic energy:, emissivity EmissivityThe ratio of the radiation intensity of a nonblack body to the radiation intensity of a blackbody. This ratio, which is usually designated by the Greek letter ε, is always less than or just equal to one...... Click the link for more information., and spectroscopy applications. The electrical engineering reference is partially based on Figures and tables of fundamental physical properties of optical materials published in 1972 by Kyoritu Shuppan Co