Force constant variation from crystalline to amorphous germanium

The phonon density of states for crystalline germanium (cz.sbnd;Ge) and amorphous germanium (aGe) have been computed by means of de Launay angular force model, considering only the first nearest neighbour interactions. The relevancy of computed phonon density of states to the interpretation of infrared and Raman spectra of az.sbnd;Ge are discussed, and the decrease in force constants of the order of 10% has been observed when the phase changes from crystalline to amorphous state.