Infrared studies of swift heavy ion irradiated C$_{60}$ thin films

The modification of fullerenes vibrational properties by energetic ion irradiation is investigated, using Fourier transform infrared (FTIR) spectroscopy . The C60 thin films have been irradiated with 200 MeV Au ions at fluence from 1 × 1012 to 1 × 1013 ions/cm2. It is observed that 577 cm−1 mode is the most sensitive but 527 cm−1 IR active mode is more resistive for swift heavy ion irradiation. To understand change in the molecular structure of fullerene molecule under swift heavy ion (SHI) irradiation, we determined damage cross-section for all four T1u (527, 577, 1183, 1428 cm−1) IR active modes. It is observed that damage cross-section (σ) is different for different vibrational modes. The effective radii (r) of the damage cylindrical zone are also evaluated