electromagnetic radiation
the optical behavior of a solid material is a function of its interactions with electromagnetic radiation having wavelengths within the visible region of the spectrum (0.4?m-0.7?m)
transparent
light is transmitted through the material with very little absorption and reflection
translucent
light is transmitted diffusely; there is some scattering within the interior of the material
opaque
virtually all light is scattered or reflected such that none is transmitted through the material
electronic polarization
the electric field component of a light wave induces a shift of the electron cloud atom around an atom relative to its nucleus
absorption and refraction of light
2 consequences of electron polarization
the absorption and then reemission of light radiation within a thin outer surface layer
metal appears opaque as a result of
excitation of electrons from occupied energy states to unoccupied ones above the Fermi energy level
absorption occurs via
the special composition of the reflected light
the perceived color of a metal is determined by
reflection
when light passes from one transparent medium to another having a different index of refraction
refraction
velocity is decreased, and the light beam is bent at the interface
relatively narrow-band-gap
opaque pure nonmetallic materials result in
band gaps greater than 3.1eV
transparent pure nonmetallic materials result in