Vibrations de réseau de quelques dérivés dihalogénés du benzène

Low frequency lattice modes of p-C6H4X2 (X = Cl, Br, I), m-C6H4I2, and o-C6H4I2 were observed by infrared absorption. Raman scattering spectra were recorded in the case of m-C6H4I2.When atomic positions were known in the unit cell (p-C6H4X2), the lattice mode frequencies were computed by the GF matrix method.The agreement between calculated and experimental values is reasonable although we did not consider the multipole–multipole long range interactions.