Thermal kinetics, 3D-FMOs and spectral phase matching of 2-aminopyridinium diphenylacetate diphenylacetic acid crystal

The bulk size title crystal is grown by adopting temperature lowering technique. The intermolecular charge transfer reactions, frontier molecular energy gaps and nonlinear optical properties have been calculated theoretically by density functional theory. The investigations on the transfer of charge occurring in the molecular system are revealed through natural bonding orbital analysis. Polarizability of the 2APD compound has been found utilizing Penn gap analysis and Claussius–Mossotti relation. Microhardness measurements were taken along three different planes to look into the anisotropicity of the grown crystal. Further, properties affecting the mechanical behaviour of the grown crystal were also discussed. The estimation of thermodynamic specifications has been calculated. The specific heat capacity of 2APD is observed to be 2.36 J g⁻¹ K⁻¹ to 4.62 J g⁻¹ K⁻¹ in the deliberate temperature range varying from 32 to 230 °C. The output signal of the 2APD sample was recorded along different angles. Bulk 2APD sample exhibits maximum intensity at θ_m = 28° ± 1°.