A first-principles study of the linear and nonlinear optical properties of isoxazole derivatives

The isoxazole derivatives gained significant attention in our daily life from better biological activity to the semiconducting materials. This study deals in depth investigation of two isoxazole derivatives, i.e. 2-[(E)-(3,4-Dimethylisoxazol-5-yl)iminomethyl] phenol (1) and 1-[(E)(3,4-Dimethylisoxazol-5-yl) iminomethyl]-2-naphthol (2) with respect to the geometric, charge transport, optoelectronic and nonlinear optical properties by density functional theory (DFT) and time-dependent DFT. The comprehensible intra-molecular charge transfer (ICT) was conceived from HOMOs to LUMOs. Strength of the electron donor groups was investigated on the absorption wavelengths, emission wavelengths, ionization potentials (IPs), electron affinities (EAs), total/partial densities of states and structure-property relationship. The smaller hole reorganization energies and superior transfer integrals of isoxazole derivatives (1 and 2) than the electron ones are leading to higher hole intrinsic mobility values as compared to the electron mobility exhibit that these systems would be good hole transport contenders. The first hyper-polarizability values are about 19 and 21 times larger than that of urea suggesting that 1 and 2 can also be considered as potential contestants for NLO applications as well.