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Refractive indices and birefringences for some representative uni-axial crystals such as II- SiP 2 and II- GeP 2 have been determined over a wide range of wavelengths by the use of first-principles electronic structure calculations. First, the calculated refractive indices are fitted usually by a generalized Sellmeier equation which consists of several oscillation terms involve in its parameters more direct information about material such as electronic transitions or resonance wavelengths. Then, in contrast to all other semiconductors under discussion our spectra show a negative birefringence for CdSiP 2 in agreement with the experimental data, and they exhibit a considerable dispersion near the band gap.

A new method for predicting optical characteristics of multilayer coatings based on calculated material properties is presented. This method combines the use of the full potential linear-augmented plane wave method (FP-LAPW) within the framework of the Density Functional Theory (DFT) and the optical matrix approach for modeling the multilayer assembly. The simulation process is applied to thin films of the II–VI semiconductors compounds. The optical constants of each thin film are determined by using the first principle calculations. Each layer is represented by the square Abeles matrix, including all necessary data in the calculation of the optical characteristics (as transmittance, reflectance and absorbance). The simulation of multilayer optical response includes the effect of thickness, light polarization and incident angle. The obtained results are helpful in the design of the multilayer systems with required properties.

First-principles study of the ground-state properties and the stability of Cd1−xZnxO solid solutions are presented using the full-potential linearized, augmented plane-wave (FP-LAPW) method in combination with the local density approximation (LDA). It is found that the structural parameters, i.e. lattice constants and bulk moduli strongly deviate from the linear function of the composition x . The equation of state of the alloys is determined and an increasing compressibility function of composition is found. The formation energy is viewed as an energetic balance between pure structural constraints and quantum chemical effects. Our calculations yield the prediction of phase separation over the whole range of concentration. This trend was explained to have a structural nature caused by the high lattice mismatch. Also, the thermodynamic stability of the alloys has been investigated.