Synthesis, Vibrational Spectroscopy, Thermal Analysis, Non-Linear Optical Properties and DFT Calculation of a Novel L-Phenylalanine Maleic Acid Single Crystals

International audienceOptically good quality new crystal of L-Phenylalanine maleic acid (LPM) was grown by slow evaporation technique. The crystalline nature of grown crystal is confirmed by X-ray diffraction analysis. Density functional theory (DFT) computations using (B3LYP) level with 6-31G (d,p) basis set gives optimized structure parameters of LPM molecule. Molecular energy gap of LPM was found by HOMO-LUMO analysis. Theoretically calculated vibrational frequencies are compared with experimentally obtained FT-IR frequencies. Optical absorption spectrum was recorded for the given crystal. Thermal stability and SHG studies were carried out for the grown crystal. Introduction. Nonlinear optical (NLO) materials are active elements for optical communications, optical switching, optical mixing and electro-optic application [1]. Combination of amino acid with an organic compound has been proposed as a new candidate for NLO application, which crystallizes in non centrosymmmetric space group. The proton donor carboxyl group (COO) and the proton acceptor amino (-NH2) group present in the amino acid contribute some physiochemical properties. The Density functional theory (DFT) calculation has now become the preferred method for understanding and predicting structure and reactivity in complex chemical system. DFT calculation along with vibrational spectral analysis is used as a promising tool to display a significant number of molecular properties of NLO materials [2]. Maleic acid forms crystalline maleate with various organic molecules through specific hydrogen bonding and π-π* interactions. Which exhibit high value of second order polarizability [3]. L-Phenylalanine is an essential protein amino acid, which is used by the body to build neurotransmitter. A sequence of second order NLO active materials composed of L-phenylalanine have been synthesized, such as, L-phenylalanine benzoic acid [4], L-Phenylalanine nitric acid [5]. In the present work deals with the experimental and theoretical investigation of L-Phenylalanine maleic acid (LPM) single crystal