Theoretical study of structural features and optical properties of the Hg3S2Cl2 polymorphs

• Some structural and optical properties of the Hg3S2Cl2 polymorphs are studied.
• Structural features of Hg3S2Cl2 compounds are discussed.
• The agreement of theoretical and experimental results is observed.

The interrelation between structural and optical properties of the Hg3S2Cl2 polymorphs have been theoretically investigated. This paper presents the results of calculations of the refractive indices and reflection coefficients for (α), (β), (γ) – Hg3S2Cl2 crystalline phases using the Harrison bonding-orbital method. The refractive indices in the spectral region far from the absorption edge were determined within the generalized single-oscillator model. The Hartree-Fock values for the valence levels were used for evaluation the energies of filled electronic states in Hg3S2Cl2 crystals. By analyzing the polarizability and susceptibility χ it is possible to calculate the refractive index and reflection coefficient; moreover the performed calculations demonstrate a satisfactory agreement with experimental results.