Optical and Theoretical studies on L-Alanine Oxalate: A Nonlinear Optical single crystal for frequency conversion application

Abstract

A nonlinear optical L-alanine oxalate (LAO) single crystal was synthesized and successfully grown by
slow evaporation technique at room temperature. The Crystal structure of the as grown crystals was determined by
single crystal X-ray diffraction analysis and is compared with the powder X-ray diffraction and theoretically stimulated
one. The functional groups are identified by Fourier transform infrared spectral analysis and compared with simulated
spectrum. The nonlinear optical efficiency of L-alanine oxalate (LAO) was determined from Kurtz Perry powder
technique and the efficiency is almost equal to that of standard KDP crystals. Thermal analysis (TG-DTA) reveals the
purity of the crystal and the sample is stable up to the melting point. HOMO–LUMO energies and first order molecular
hyper polarizability of L-alanine oxalate (LAO) have been evaluated using density functional theory (DFT) employing
B3LYP functional and 6-31G (d,p) basis set. Dielectric constant and dielectric loss of L-alanine oxalate (LAO) are
measured in the frequency range from 50 Hz to 5 MHz at room temperatures.