Pressure dependence of the optical properties of α, β and ω phases of titanium

In this study, the pressure dependence of the optical properties of hexagonal close-packed, body-centered cubic and hexagonal phases of titanium was investigated using density functional theory. When Ti phases were compressed, the position of critical points such as equilibrium constants, static dielectric constants and also the main peaks in optical spectra shifted with an increase or decrease in energy compared to that at zero pressure. The imaginary dielectric function of all the phases under normal pressure and hydrostatic pressure was calculated. Under hydrostatic pressure, the optical conductivity of α phase increased, and the main peaks moved toward higher energies. Moreover, our results showed that the optical properties of α and ω phases change more than those of β phase. It was also demonstrated that the intensity of peaks of the energy loss function increased from α to β and decreased from β to ω. The optical reflectivity and absorption coefficient increased under pressure effects.