title: A quantitative view of charge transfer in the hydrogen bond: the water dimer case.
abstract: The hydrogen bond represents a fundamental intermolecular interaction that binds molecules in vapor and liquid water. A crucial and debated aspect of its electronic structure and chemistry is the charge transfer (CT) accompanying it. Much effort has been devoted, in particular, to the study of the smallest prototype system, the water dimer, but even here results and interpretations differ widely. In this paper, we reassess CT in the water dimer by using charge-displacement analysis. Besides a reliable estimate of the amount of CT (14.6 me) that characterizes the system, our study provides an unambiguous context, and very useful bounds, within which CT effects may be evaluated, crucially including the associated energy stabilization.
authors.affiliation: Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia via Elce di Sotto 8, I-06123 Perugia (Italy); Istituto di Scienze e Tecnologie Molecolari del CNR via Elce di Sotto 8, I-06123 Perugia (Italy). enrico@thch.unipg.it.
authors.forename: Enrico
authors.initials: E
authors.lastname: Ronca
authors.forename: Leonardo
authors.initials: L
authors.lastname: Belpassi
authors.forename: Francesco
authors.initials: F
authors.lastname: Tarantelli
mesh_terms: D019281:Dimerization; D006860:Hydrogen Bonding; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water
keywords: ab initio calculations; charge transfer; hydrogen bonds; intermolecular interactions; water dimer