Far Infrared Vibrational Spectroscopy in CrSi_2

We present and discuss reflectance and trasmittance measurements on CrSi, polycrystalline films in the (100 + 700) cm-' wavenumber range. The spectra show that the compound has a nonmetallic behaviour. The strong and sharp structures observed are interpreted on the basis of the symmetry properties of the normal modes of CrSie, and their strength is attributed to a dynamical charge. Moreover, preliminary lattice dynamicscalculations allow to explain the relative intensity of the infrared-active modes.