Raman and infrared study of 100 MeV swift Ag~(8+) heavy ion irradiation effects in CaSO_4 centre dot 2H_2O single crystals

摘要

The modifications of calcium sulphate (CaSO_4 centre dot 2H_2O) single crystals are investigated by means of Raman and Fourier transform infrared spectroscopy (FT-IR) using 100 MeV Ag~(8+) ions in the fluence range 1 X 10~(11) to 5 X 10~(13) ions/cm~2. It is observed that the intensities of the Raman modes decrease with increase in ion fluence. We determined damage cross-section (sigma) for all the Raman active modes and found to be different for different Raman modes. Further, FT-IR studies have been carried out to confirm surface amorphisation for a fluence of 1 X 10~(13) ions/cm~2. It is observed that the absorption peaks at 1132-1156 cm~(-1) corresponds to v_3(SO_4~(2-)) mode. The decrease in Raman peaks intensity with ion fluence is attributed to degradation of v_3(SO_4~(2-)) modes present on the surface of the sample.