Infrared absorption in bulk amorphous As

We report the room-temperature infrared absorption spectrum of bulk a-As. The spectrum shows strong features in two well-separated spectral regions, near 230 cm^-1 and between 150 and 110 cm^-1 The absorption in a-As is compared with absorption reported previously for a-Se and a-Ge. The absorption in all three elemental amorphous materials corresponds to structure in the vibrational density of states and is discussed in terms of a structural model that is based on the atomic coordination and resultant short-range order.