Knowledge Bank

Published information on the Kramers-Kronig (KK) dispersion analysis of the LiF infrared reflectance band indicates the presence of physically impossible results, namely, significant portions of the phase angle and absorption index spectra are distorted and/or are negative. The published reflectance data have been carefully evaluated. By applying the mean value integral theorem and the concept of central frequency to the KK transforms a mathematically unique reflectance curve has been constructed. The final KK analysis yields for the first time a phase angle spectrum which is physically plausible and absorption index values which are in excellent agreement with experimental measurements.