engleski

Density Functional Calculation of Raman Intensity in High Pressure Phases of TiO_2 Crystal

Intensity of Raman lines are important part of the information contained in the vibrational spectra of crystals. Due to the changes in the crystal structure as a response to external perturbation (pressure, temperature) the frequencies, as well as intensities of the Raman active modes change under external influence. The intensity of the Raman lines is important information about the properties of studied system, but is usually not used very much. The Raman study of a oriented single crystal gives information about the components of Raman tensor for various Raman active modes. We calculate intensities of Raman modes of tetragonal rutile structure, space group P42/mnm, of TiO_2 crystal for different pressures. The ABINIT density functional program package is used for the calculation of vibrational frequencies and Raman tensor components. The values given by calculations are in a fair agreement with the observed positions of phonons as a function of pressure. The possibility to use Raman intensities as additional tool in the study of phase transitions is discussed.

DFT ; DFPT ; Raman ; TiO_2

nije evidentirano