Photon dispersion associated with optic-vibrations

In this communication, an effect of the damping coefficient on the dielectr ic function and dispersion is discussed. We recalculate Li's result [Li Xin -Qi, Yasuhiko Arakawa, Solid State Commun., 108 (1998) 211] and present a m ore general dielectric function associated with optic-vibrations. The relat ion between the phonon wavevector and the dispersion has also been obtained . The theoretical results show that the wavevector will obviously affect th e profile of the dielectric function and result in the peak of the profile shift and increasing. (C) 1999 Elsevier Science Ltd. All rights reserved.