Impact of low dose of gamma irradiation on thin films of Bismuth Tri-iodide.

Thin films of Bismuth Tri-iodide BiI were synthesized on a glass substrate by the thermal vacuum deposition technique. Films were exposed to gamma radiations of two doses 10 Gy and 50 Gy. Structural and optical properties of films were studied through X-ray Diffraction and UV spectroscopy both before and after the gamma irradiation.

Lattice vibrations of AVO4 crystals (A=Lu, Yb, Dy, Tb, Ce).

A short range force constant model has been applied using normal coordinates to investigate the Raman and the infrared wavenumbers in rare earth AVO4 compounds (A=Lu, Yb, Dy, Tb, Ce) having space group I41/a and symmetry C4h(6). The calculation of zone center phonons has been made by using four stretching and five bending force constants. The calculated Raman and infrared wavenumbers are in very good agreement with the observed ones.