Nonlinear Optical Properties of Organic Molecules: A DFT Study

Abstract The organic materials have attracted many attentions particularly in terms of their nonlinear optical (NLO) performance, due to their growing and prospective applications in possible photonic devices. In this study, we used the density functional theory to study the polarizability (<α>), the anisotropy of the polarizability (<Δα>), ground- state dipole moment (μ) and the first-order hyperpolarizability (β) of the lycopene, caffeine and capsaicin molecules. We used the B3LYP levels of the theory with 6-311G(d,p) basis set. Also, the electronic properties of molecules, such as the electron density map, the highest occupied orbital, and the lowest unoccupied orbital were calculated. The quantum chemical descriptor of molecules such as HOMO-LUMO energy gap (ΔE), electron affinity (A), ionization potential (I), global hardness (η), electronegativity (χ), chemical potential ( π ), and global electrophilicity index (ω) are investigated.