The usefulness of the first-principles calculations of optical properties of the materials and the type of information that can be accessed by them

Computational experiments based on density functional theory (DFT) constitute a valuable tool for the study of atomistic properties of materials for a long time. This short review is focused on one specific part of DFT calculations that refers to a description of the linear optical response of the systems. It is intended to emphasize the importance of the optical calculations and their utility of accessing directly or indirectly the other important properties of the studied materials, frequently hardly accessible from experiments. It is demonstrated how the optical calculations can be used to test the true electronic structure and magnetic order, interpret the experimental optical spectra, characterize different types of defects and determine the magneto-optic properties of the materials. Examples have been chosen from the authors’ research published in the last decade.