Density functional studies on the two conformers of 2-fluoro-4,6-dinitrophenol: vibrational assignment based on potential energy distribution

The molecular structures as well as vibrational frequencies for two conform ers of 2-fluoro-4,6-dinitrophenol are calculated with density functional th eory using the BLYP functional and the 6-31G(d,p) basis set. As expected, t he results show the greater stability and stronger hydrogen bond for the co nformer with the intramolecular hydrogen bond to the nitro group. A detailed assignment of the vibrational spectra is made on the basis of th e calculated potential energy distribution. Due to the lack of both structu ral data and infrared spectra in the gas phase for the investigated complex es, the results are compared to structurally related o-nitrophenol, for whi ch both experimental and theoretical data are available. A detailed discuss ion of the characteristic bands in the infrared spectra of the investigated species is presented. (C) 2000 Elsevier Science B.V. All rights reserved.