A new approach to the problem of the hydrogen bond spectra of the adipic acid crystal: the polarization and temperature effects

• Published in: Journal of molecular structure. Theochem Vol. 285; no. 3; pp. 281 - 292
• Main Author: Flakus, Henryk T.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 22.10.1993; Elsevier Science
• Subjects: Atomic and molecular physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Infrared and raman spectra and scattering; Infrared spectra; Molecular properties and interactions with photons; Molecular spectra; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Organic compounds, polymers; Physics; Line shape; Crystals; Infrared spectra; Experimental study; Intermolecular interaction; Hydrogen bonds; Isotope effects; Temperature effects; Dichroism; Solid phase; Adipic acid; Vibrational states; Organic compounds
• ISSN: 0166-1280; 1872-7999
• DOI: 10.1016/0166-1280(93)87043-D

This paper attempts to provide a new interpretation of some complex spectral effects observed in the IR spectra of the hydrogen bond in the adipic acid crystal. The subjects of our interest are the effects corresponding to the abnormal linear dichroism, the influence of temperature, and the isotopic substitution of deuterium in the H-bonds, measured in the v OH and the v OH band ranges in the crystalline spectra. In this paper a critical review of some recent solutions to the problem is given, and a new “strong coupling” approach for the crystalline spectral properties proposed. Based on the model calculations it is shown that the “strong coupling” model is able to quantitatively reproduce the v OH and v OD band shapes in the spectra of the adipic acid crystal, a fact which can be considered as a basis for an explanation of the isotopic, polarization and temperature effects in the spectra. The key property of the crystal responsible for the abnormal spectral properties of the hydrogen bonds seems to be the statistical disorder in the crystalline lattice. The H-bonds bent up or down with respect to the ring formed by the two linked COOH groups are considered to be the main source of the spectral effects analyzed, along with the very specific selection rules in the IR for the centrosymmetric H-bonded dimers.