Density functional theory studies on molecular structure and vibrational spectra of NLO crystal l-phenylalanine phenylalanium nitrate for THz application

• Published in: Journal of molecular structure Vol. 1006; no. 1; pp. 513 - 526
• Main Authors: Amalanathan, M., Hubert Joe, I., Rastogi, V.K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 14.12.2011
• Subjects: absorption; Activation; Charge transfer; chemical structure; Density functional theory; Frequency ranges; hydrogen bonding; Hyperpolarizability; Intramolecular charge transfer; Mathematical analysis; Molecular structure; NBO; Nitrates; Orbitals; phenylalanine; spectroscopy; Terahertz spectrum; Vibrational spectra; Terahertz spectrum; NBO; Molecular structure; Hyperpolarizability; Vibrational spectra; Intramolecular charge transfer
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2011.09.060

► Structural analysis and the vibrational spectral analysis have been carried out to understand the NLO activity. ► Hydrogen bonding and charge transfer interactions are also analyzed. ► THz spectra of LPAN also discussed. Molecular structure, FT-IR and Raman spectra of l-phenylalanine phenylalanium nitrate have been investigated using density functional theory calculation. The polarizability and hyperpolarizability value of the crystal is also calculated. Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction. Simultaneous activation of ring C C stretching modes shows the non-centrosymmetric symmetry. Terahertz time-domain spectroscopy has been used to detect the absorption spectra in the frequency range from 0.05 to 1.3 THz. Theoretically predicted β value exhibits the high nonlinear optical activity.