Vibrational spectra, optical properties, NBO and HOMO-LUMO analysis of L-Phenylalanine L-Phenylalaninium Perchlorate: DFT calculations.
In this work, we report a combined experimental and theoretical study of a nonlinear optical material, L-Phenylalanine L-Phenylalaninium Perchlorate. Single crystals of the title compound have been grown by slow evaporation of an aqueous solution at room temperature. Theoretical calculations were preceded by redetermination of the crystal X-ray structure. The compound crystallizes in the non-centro symmetric space group P2(1)2(1)2(1) of the orthorhombic system. The FT-IR and Raman spectra of the crystal were recorded and analyzed. The density functional theory (DFT) computations have been performed at B3LYP/6-31G(d) level to derive equilibrium geometry, vibrational wavenumbers, intensity and NLO properties. All observed vibrational bands have been discussed and assigned to normal mode or to combinations on the basis of our DFT calculations as a primary source of attribution and also by comparison with the previous results for similar compounds. Natural bond orbital analysis was carried out to demonstrate the various inter-and intramolecular interaction that are responsible of the stabilization of the compound. The lowering of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap appears to be the cause of its enhanced charge transfer interaction leading to high NLO activity.
Laboratoire de Physique Appliquée (LPA), Faculté des Sciences 3018, BP 802 Sfax, Tunisia. Electronic address: nabil.elleuch@gmail.com.
Nabil
N
Elleuch
Laboratoire de Physique Appliquée (LPA), Faculté des Sciences 3018, BP 802 Sfax, Tunisia.
Ali
A
Ben Ahmed
Laboratoire de Physique Appliquée (LPA), Faculté des Sciences 3018, BP 802 Sfax, Tunisia.
Habib
H
Feki
Laboratoire de Physique Appliquée (LPA), Faculté des Sciences 3018, BP 802 Sfax, Tunisia.
Younes
Y
Abid
Laboratoire de Chimie Théorique (LCT), Université Pierre et Marie Curie, Paris VI, France.
Christian
C
Minot
D000838:Anions; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D055620:Optical Phenomena; D010472:Perchlorates / Q000737:chemistry*; D010649:Phenylalanine / Q000737:chemistry*; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D014732:Vibration
D000838:Anions; D010472:Perchlorates; D010649:Phenylalanine; C494474:perchlorate
DFT; FT-IR; First hyperpolarizability; NBO analysis; Raman; TD-DFT