Quantum-Chemical Modeling of Dispersed Systems with the Yttrium Aluminum Garnet Base

The laser material Y 3 Al 5 O 12 (YAG), originally known in the form of a single crystal, has become widespread and widely commercialized in the form of optical ceramics. The desire to expand by the size effect the functionality of materials made from nanocrystals actualizes studying the influence of their structure on the optical (vibrational and electronic) and other properties of new promising materials with the YAG base, including glass ceramics. In this work, models of crystalline yttrium aluminum garnet fragments have been calculated using the DFT/uPBEPBE/SDD, DFT/uPBEPBE/lanl2DZ, and DFT/uB3PW91/SDD methods. Infrared spectra have been calculated using the DFT/uPBEPBE/lanl2DZ method, and absorption bands at calculated wave numbers have been correlated with the measured ones. The electronic absorption spectrum and level energies have been calculated using the DFT/RB3PW91/SDD method.