| Abstract
| - The molecular structure of para-fluorophenol (p-FPhOH) has been calculated using the MP2 and densityfunctional (B3LYP) methods with the extended 6-311++G(df,pd) basis set. The gas-phase structure of thismolecule has not been reported, as yet. For the series of phenols, p-XPhOH (X = H, F, Cl, Br), the calculatedgeometrical parameters and natural atomic charges are compared and discussed. It is shown that in para-fluorophenol, the structural changes of the ring are governed chiefly by the electronegativity of fluorine(inductive effect). However, resonance effects induced by the OH and F substituents in the para position alsocontribute to the geometrical changes of the aromatic ring. The FT-IR spectra of p-fluorophenol and its OD-deuterated derivative (p-FPhOD) in carbon tetrachloride and cyclohexane solutions were measured, in thefrequency range of 3700−400 cm-1, and the experimental integrated infrared intensities were determined.The harmonic frequencies and IR intensities of p-FPhOH and p-FPhOD were calculated with the B3LYPmethod using the 6-311++G(df,pd) basis set. The unequivocal assignment of the experimental spectra hasbeen made on the basis of the calculated potential energy distribution, PED. The characteristic “marker” IRbands for phenol and its para-halogeno derivatives are discussed. The unusual quenching of the infraredintensities of several bands in the spectra of p-fluorophenol has been explained.
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