Hydrogen bonds with large proton polarizability in crystals

In crystals with hydrogen bonds infrared continua are sometimes observed. T hey demonstrate that in crystals hydrogen bonds may show large proton polar izability. Heteroconjugated OH ... N reversible arrow O- ... H+N bonds pres ent in phenol + amine crystals as well as long, weak N+H ... N reversible a rrow N ... H+N bonds are discussed. Furthermore, results with short, strong O- ... H+...O- bonds formed in carboxylic acid-carboyxlate crystals are co nsidered. It is shown that in crystals a continuum of energy levels arises due to the interaction of the polarizable hydrogen bonds via proton dispers ion forces. The nature of these forces is explained; they are attractive fo rces. (C) 2000 Elsevier Science B.V. All rights reserved.