Dispersion of linear and non-linear optical susceptibilities for amino acid 2-aminopropanoic CH3CH(NH2)COOH single crystals: experimental and theoretical investigations

Abstract

A comprehensive experimental and theoretical investigation of dispersion of the linear and nonlinear optical susceptibilities for amino acid L-alanine single crystals is reported. The state-of-the-art full potential linear augmented plane wave method, within a framework of the density functional theory was applied. The atomic positions from X-ray diffraction have been optimized so that the force on each atom is around 1 mRy au À1 . This relaxed geometry has been used for the theoretical calculations. The complex dielectric susceptibility dispersion, its zero-frequency limit and the birefringence of amino acid L-alanine single crystals were studied. The crystal exhibits a large uniaxial dielectric anisotropy resulting in a significant birefringence. The calculated birefringence at static limit is 0.072 and 0.074 at l ¼ 1064 nm (corresponding to 1.165 eV) in good agreement with the measured value (0.073). We also report calculations of the complex second-order optical susceptibility dispersions for the principal tensor components: c (2) 123 (u), c (2) 231 (u) and c (2) 312 (u). The calculated second order susceptibility tensor components |c (2) 123 (u)|, |c (2) 231 (u)|, and |c ( 2) 312 (u)| at l ¼ 1064 nm are compared with those obtained from our measurements performed using the 25 ps Nd:YAG pulsed laser at l ¼ 1064 nm. Our calculations are in reasonably good agreement with our experimental data. In addition we have calculated the microscopic second order hyperpolarizability, b 123 , vector component along the principal dipole moment directions for the dominant component c (2) 123 (u) and it is found to be 0.21 Â 10 À21 pm V À1 in the static limit and 0.27 Â 10 À21 pm V À1 at 1.165 eV (l ¼ 1064 nm) in comparison with our measured value (0.31 Â 10 À21 pm V À1 ) at l ¼ 1064 nm. Additional study of the second order susceptibilities versus the external laser treatment is performed.

FP-LAPW investigation of mechanical and thermodynamic properties of Na2X (X = S and Se) under pressure and temperature effects

“…This method has proven to be one of the most accurate methods for the computation of the electronic structure of solids within DFT [40][41][42][43][44][45]. In this scheme of calculations APW+lo basis set is incorporated to represent the electronic band structure for all atoms as well as corresponding orbitals.…”

First Principles Study of Mechanical Stability and Thermodynamic Properties of K2S under Pressure and Temperature Effect

“…This method has proven to be one of the most accurate methods for the computation of the electronic structure of solids within DFT [33][34][35][36][37][38], implemented in the WIEN2k code [39] has been applied for the study of structural, elastic, electronic, and thermodynamic properties of anti-CaF 2 structure type. Generalized gradient approximation based on the PerdewBurke-Ernzerhof (PBE-GGA) functional [40,41] has been used to determine the optimized structure of these compounds.…”

Dispersion of the linear and nonlinear optical susceptibilities of the CuAl(S1−xSex)2 mixed chaclcopyrite compounds

“…The calculations were repeated until the following convergence tolerance parameters were achieved: energy 10 À5 eV/atom, maximal force and stress 0.03 eV/Å and 0.05 GPa, respectively, the maximal displacement 0.001 Å . The compositional dependence of the calculated properties was studied by gradual replacement of the S atoms in the CuAlS 2 unit cell by the Se atoms, corresponding to the Se concentration (in %) of 0, 25 36 This is an implementation of the DFT. Exchange and correlation potential was described by the GGA of PBE, which is based on exchangecorrelation energy optimization to calculate the total energy.…”

“…19 The specific A XI B XIII C XVI 2 chalcopyrites concerned in this work used copper as the group XI element, aluminum as the group XIII element, and sulfur or selenium as the group XVI element (the standard group numbering of the chemical elements in the periodic table is used, as recommended by the International Union of Pure and Applied Chemistry (IUPAC)). Since these compounds display large birefringence, [25][26][27][28] they are potentially interesting as nonlinear optical materials, as well as semiconductors, whose band gap favors their applications for solar energetic. So far, however, the trends of the coupling coefficients in these materials are a)…”