VIBRATIONAL ANALYSIS OF PHENOL (METHANOL)(1)

Ab initio calculations at the Hartree-Fock 4-31G level were performed in order to calculate binding energies and vibrational frequencies of the phenol/CH3OH-cluster and two deuterated isotopomers (d-phenol/CH3 OD, d-phenol-CD3OD). The minimum energy structure is trans-linear, as for the phenol/H2O-cluster. The calculated frequencies of phenol and m ethanol as well as the intramolecular frequencies of the phenol/CH3OH- cluster are assigned to experimental values. The calculated intermolec ular frequencies of the phenol/CH3OH-cluster are compared with the ava ilable experimental frequencies of the S0 (and S1)-state of the phenol /methanol-cluster and the similar p-cresol/methanol-cluster. Assignmen ts are suggested for the sigma and rho1-mode. In order to clarify the assignment of the low frequency vibration at 22 cm-1 anharmonic correc tions for the beta2-mode of the phenol/CH3OH-cluster are calculated. T hese calculations show only slight anharmonicity compared with the bet a2-mode calculations carried out for the phenol/H2O-cluster.