Growth, linear optical constants and photoluminescence characteristics of beta-alaninium picrate (BAP) crystals

Beta-alaninium picrate (BAP), an organic optical material was synthesized and single crystals were grown by slow evaporation solution technique. The cell parameters were determined from the single crystal X-ray diffraction analysis. The optical properties of the BAP crystals were investigated using spectrophotometric measurements in the wavelength range from 190 to 1100 nm. From the UV-vis-IR transmittance data, the optical band gap as function of photon energy was estimated. The optical constants such as absorbance, reflectance, extinction coefficient, refractive index, optical and electrical conductivities, electric susceptibility, complex dielectric constant, lattice dielectric constant and the ratio of free charge carrier concentration to the effective mass were calculated for the first time from the optical transmittance data of the grown BAP crystals. The dispersion of the refractive index was discussed in terms of the Wemple-Didomenico single oscillator model and using this model, the refractive index dispersion parameters like oscillator energy, dispersion energy, oscillator strength, static dielectric constant and static refractive index were determined. Photoluminescence studies were also carried out for the grown BAP crystal.