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The revision of intermolecular interactions in 1,3‐dinitrobenzene crystal—the role of nitro groups in optical nonlinearity
Author(s) -
TrzebiatowskaGusowska M.,
Piela K.,
Misiaszek T.,
Szostak M. M.,
Baran J.
Publication year - 2010
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2575
Subject(s) - nitro , intermolecular force , raman spectroscopy , nonlinear optical , crystal (programming language) , chemistry , dinitrobenzene , group (periodic table) , nonlinear system , crystallography , organic chemistry , physics , molecule , quantum mechanics , computer science , alkyl , programming language
Polarized Fourier transform‐infrared (FT‐IR) reflectance spectra and powder Raman spectra have been measured for 1,3‐dinitrobenzene crystal in order to revise the assignments of bands by means of the oriented gas model reinforced with quantum chemical [density functional theory (DFT)] calculations. Longitudinal optical/transverse optical (LO‐TO) splitting of some bands is observed indicating medium strong, long‐range, dipole–dipole interactions. The analysis of overtones in the polarized FT‐NIR spectra has allowed us to estimate the anharmonicity of vibrations in the crystal. The molecular motions of the nitro groups are analyzed on the basis of temperature‐dependent polycrystalline IR spectra. Based on the values of the energy difference (Δν el ) between the forbidden A 1g →B 2u transition in the benzene molecule in the gas phase and the first electronic transition in 1,3‐dinitrobenzene, it has been concluded that the intermolecular interactions are medium strong. The nitro group interactions are proposed to play the main role in the optical nonlinearity. Copyright © 2010 John Wiley & Sons, Ltd.