<b>Effect of Swift Heavy Ion irradiation on Optical properties of Poly vinylidene chloride PVDC Films</b> The lithium ion 50 MeV having fluence range of 1x1011 ions cm2 to 3x1012 ions cm2 induced poly vinylidene chloride PVDC films have been examined using UV Visible technique. The shift in optical absorption edge in irradiated PVDC was associated with the decrease in optical band gap energy. The noticeable characteristic peak was detected due to UV Vis analysis, in lithium irradiated samples of PVDC at highest fluence. Polymer, Irradition, PVDC Poly vinylidene chloride , SHI Swift Heavy Ion , UV VIS Ultra violet visible 50-52 Issue-5 Volume-1 Kusam Devgan