LAUSR

Inorganic crystals are advantageous for use as second harmonic generation (SHG) materials because of their large laser damage threshold and mechanical strength. Here, we focus on the defect pyrochlores based on mixed oxides of MoO3, Ta2O5, Cs2O, and Nb2O5, which were synthesized recently. We predict the linear optical properties (refractive indices and linear polarizabilities) and nonlinear ones [first hyperpolarizabilities and nonlinear optical (NLO) tensors] for the crystals of the defect pyrochlores CsNbMoO6 and CsTaMoO6 using the coupled-perturbed Hartree–Fock/Kohn–Sham method (CPHF/KS) in both full-electron and pseudopotential basis sets. To identify the more accurate computational protocol, the crystals KH2PO4, LiNbO3, (NH2)2CO, and α-SiO2 were used as benchmarks. The best agreement of the predicted NLO parameters with experimental ones is achieved in calculations at the density functional theory/PBE0 level in the POB-TZVP basis. This agreement becomes quantitative when the dimensionless relative va...