Electrons and phonons in amorphous pyramidally bonded solids

Electronic and phonon state densities of amorphous pyramidally bonded solids are calculated with As as a prototype. Using a Bethe-lattice, the Greaves-Davis random network model and the Cluster-Bethe-lattice method, the results show: (1) the phonon states are isomorphic to, and $\text{obtained}$ from, the p-like electron states, (2) the photoemission and infrared measurements are easily interpreted, and (3) the electronic and phonon state densities are $\text{extremely}$ sensitive to the local topology.