Synthesis, spectroscopical and DFT studies on third order NLO crystal: Sodium bis(malonato)borate monohydrate (SBMBM)

The single crystal of sodium bis(malonato)borate monohydrate (SBMBM) was grown using the Slow Evaporation Solution Technique(SEST). To analyze the crystal lattice parameters of the grown SBMBM crystal, Single Crystal X-Ray Diffraction analysis were used. The results shows that the crystal belongs to Triclinic crystal system with space group P2₁/n with lattice parameters A = 7.9058 (4) Å, B = 8.2979 (5) Å, and C = 14.6473 (9) Å, where α = 90°, β = 101.565 (2)°, and γ = 90° The theoretical calculation utilizing HF/LANL2DZ and the experimental results agree rather well. The molecular optimized geometry, FT-IR, and the energy gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were calculated using the HF/LANL2DZ basis set. The several functional groups in the SBMBM crystal are investigated by FT-IR spectrum. Studies of UV–visible NIR transmittance indicate that the crystal has a high transmittance throughout the whole visible spectrum. Using the Z-scan technique, third-order nonlinear optical (NLO) property of SBMBM crystal is analysed, and the linear and nonlinear refractive index are computed. χ³ = 4.49 × 10⁻⁶esu is the third-order nonlinear optical susceptibility.