Swift heavy ion irradiation induced phase transformation in calcite single crystals

Ion irradiation induced phase transformation in calcite single crystals have been studied by means of Raman and infrared spectroscopy using 120 MeV Au9+ ions. The observed bands have been assigned according to group theory analysis. For higher fluence of 5×1012 ion/cm2, an extra peak on either side of the 713 cm−1 peak and an increase in the intensity of 1085 cm−1 peak were observed in Raman studies. FTIR spectra exhibit extra absorption bands at 674, 1589 cm−1 and enhancement in bands at 2340 and 2374 cm−1 was observed. This might be due to the phase transformation from calcite to vaterite. The damage cross section ( σ ) for all the Raman and FTIR active modes was determined. The increase of FWHM, shift in peak positions and appearance of new peaks indicated that calcite phase is converted into vaterite.