Vibrational density of states of rare-gas crystal doped with impurities.

Abstract

The vibrational density of states of disordered XeI, 2Cs2, and Xei 1-2,Kt2 crystals is studied for x < 0.05. It is obtained as an average of local densities of states, which are calculated bythe continued-fraction method. Two sets of asymptotic values for this expansion are used for a satisfactory approximation of both the main band and the minority peaks outside it. The use of a bond-stretching coordinate basis allows a physical interpretation of each local density of states and also gives simple kinetic and force constant matrices. The drawback of over completeness of this basis is easily overcome.