Abstract
Recent status of optical response spectra calculations is reviewed, illustrating various bulk, surface, and interface systems. One can obtain fruitful information on atomic and electronic structures using the freedom of light such as energy (wave length) and polarization. Moreover, by explaining the spectral shape origin in reflectance difference spectroscopy, we show that the optical response of surface and interface has quite different features and needs different calculation methods from those of bulk systems, reflecting the breakdown of translational symmetry.
