DENSITY-FUNCTIONAL AND DENSITY-FUNCTIONAL REACTION FIELD CALCULATIONSOF THE MOLECULAR-PROPERTIES OF PHENOL

Several molecular properties of phenol in the gas phase and in a diele ctric medium representing liquid water were calculated. The calculatio ns were based on ab initio and density-functional methods. It is shown that the latter provide a good description of the molecular propertie s of phenol. An analysis of the electrostatic solvent effects on these properties, based on the self-consistent reaction field, indicates th at the influence of a polar dielectric environment on the molecular pr operties of phenol is modest. The most significant changes, when a com parison is made with gas phase properties, concern the red shift of th e vibrational modes related to the C-H and O-H stretching vibrations, This result is in keeping with recent studies of phenol-(H2O)(n) (n = 1, 3) complexes, which predicted a significant red shift for the pheno lic O-H vibration with an increase in n. The importance of this effect seems, however, to be considerably reduced in the uniform dielectric environment and this result also suggests that the underestimation of the electrostatic solvent effects on the molecular properties of pheno l is related to the limitations of the present approach based on the O nsager model.