First-principles, UV Raman, X-ray diffraction and TEM study of the structure and lattice dynamics of the diamond–lonsdaleite system

We report the results of the study of the polycrystalline powder of the diamond–lonsdaleite system by X-ray diffractometry, transmission electron microscopy and UV Raman spectroscopy. The measured data of structural parameters are in good agreement with ab initio calculations. We show that the Raman spectrum is proportional to the phonon density of states of the diamond–lonsdaleite system. ► Polycrystalline powder of the diamond–lonsdaleite system was synthesized. ► The presence of diamond and lonsdaleite layers of approximately equal content was confirmed by X-ray diffractometry and transmission electron microscopy. ► UV Raman spectra of the diamond–lonsdaleite system were obtained and analyzed. ► The frequencies, intensities of vibrational modes and phonon density of states for lonsdaleite were ab initio calculated. ► We have shown that the Raman spectrum of the diamond–lonsdaleite system is proportional to the phonon density of states.