CH Stretching Overtone Spectra of Fluorine Substituted Toluenes

Autor:	Zimei Rong, Chenxi Zhu, Bryan R. Henry
Rok vydání:	2003
Předmět:	Aryl Overtone Anharmonicity Torsion (mechanics) Photochemistry Molecular physics Spectral line chemistry.chemical_compound chemistry Ab initio quantum chemistry methods Fermi resonance Rigid rotor Physics::Chemical Physics Physical and Theoretical Chemistry
Zdroj:	The Journal of Physical Chemistry A. 107:10771-10780
ISSN:	1520-5215 1089-5639
DOI:	10.1021/jp0305887
Popis:	We have measured and analyzed the vapor phase CH stretching overtone spectra of 3,5-difluorotoluene, 2,3,5,6-tetrafluorotoluene, and 2,3,4,5,6-pentafluorotoluene. The aryl bands are complex due to Fermi resonance. We have used a two-level system model to analyze the Fermi resonance within the aryl bands. The aryl regions of the overtone spectra are “corrected” for Fermi resonance and interpreted as uncoupled stretching oscillators. The methyl band profiles are complex due to the coupling between CH stretching and methyl torsion. The methyl band profiles are simulated with a CH stretching methyl torsion model. The CH stretching modes are described by a harmonically coupled anharmonic oscillator local mode model, and the methyl torsion is described by a rigid rotor model. Simulation parameters are obtained from ab initio calculations with the HF/6-31G(d) method. Relative intensities of aryl and methyl contributions in the CH stretching overtone spectra in the region ΔvCH = 2−5 are measured and calculated fo...
Databáze:	OpenAIRE
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