Structure and vibrations of phenol(H2O)2

Abstract

Extensive ab initio calculations at the Hartree–Fock (HF) level using different basis sets have been performed in order to obtain the minimum energy structure of the phenol(H₂O)₂‐cluster. Several hydrogen bonding arrangements and a van der Waals structure are discussed. The most stable structure turns out to be cyclic with nonlinear hydrogen bonds. This structure is similar to the one calculated for the water trimer. In contrast with the water trimer the average binding energy of a hydrogen bond decreases with increasing cluster size of Ph(H₂O)_n (n=1,2). This is a result of non equal hydrogen bonds. A normal coordinate analysis has been carried out for the fully optimized minimum energy structure of phenol(H₂O)₂ and its deuterated isotopomer d‐phenol(D₂O)₂. The calculated harmonic intramolecular vibrational modes are compared with experimental values and the intermolecular stretching vibrations are assigned.