Phenol O–H Bond Dissociation Energy in Water Clusters P. CABRAL DO COUTO, 1,2 R. C. GUEDES, 1,2 B. J. COSTA CABRAL, 1,2 J. A. MARTINHO SIMÕES 1,3 1 Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal 2 Centro de Física da Matéria Condensada da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa, Portugal 3 Centro de Ciências Moleculares e Materiais, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal Received 6 June 2000; revised 14 June 2001; accepted 28 June 2001 ABSTRACT: We are reporting ab initio and density functional theory (DFT) calculations for the phenol O–H bond dissociation energy in the gas phase and in phenol–water clusters. We have tested a series of recently proposed functionals and verified that DFT systematically underestimates the O–H bond dissociation energy of phenol. However, O–H bond dissociation energies in water clusters are in reasonable agreement with experimental data for phenol in solution. We have evaluated electronic difference densities in phenol–water, phenoxy–water, and water, and we are suggesting that the representation of this quantity gives an interesting picture of the electronic density rearrangement induced by hydrogen bond interactions in phenol–water clusters. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem 86: 297–304, 2002 Key words: O–H bond energy; ab initio; density functional theory; water clusters; phenol–water clusters Correspondence to: B. J. Costa Cabral; e-mail: ben@adonis.cii.fc. ul.pt. Contract grant sponsor: Fundação para a Ciência e a Tecnolo- gia (FCT). Contract grant number: PRAXIS XXI/BD/15920/98. Contract grant sponsor: SAPIENS Program, Portugal. Contract grant number: QUI/35406/99-00. International Journal of Quantum Chemistry, Vol. 86, 297–304 (2002) © 2002 John Wiley & Sons, Inc. DOI 10.1002/qua.1110