Determination of Optical Constants of in Bi from Reflectance Measurements

A fall in reflectance was noted from values obtained for a freshly cleaved sample to values obtained after periods of exposure of the surface to air. The decrease in reflectance with increased exposure time is attributed to formation of a surface layer insoluble in Freon or ethyl alcohol; it is assumed to be a tarnish layer. Computer processing was employed to calculate optical constants from reflectance data.