Molecular mirror images, dense ice phases, organic salts at interfaces, and electrochemical deposition: exotic applications of the Pirogov-Sinai theory

The Pirogov-Sinai theory of phase transitions is used to prove the existenc e of ordered molecular phases at low temperatures in statistical mechanical models for several types of molecular systems. A three-dimensional lattice gas containing two molecular mirror images (enantiomers) was proved to und ergo enantiomeric phase separation for one domain of interactions and to co ntain ordered racemic phases for another domain of interactions. A model fo r ice VII, which contains disordered hydrogen bonds, was introduced and pro ved to undergo a transition to a low-temperature phase which has the ordere d hydrogen-bonded structure of ice VIII. A lattice gas model for guanidiniu m nitrate at the mercury-water interface was introduced and proved to form a condensed monolayer with an open, hexagonal hydrogen-bonded structure tha t agrees with the structure proposed on the basis of experiments. A model f or the underpotential deposition of copper on the (111) surface of a gold e lectrode in the presence of bisulfate was proved to undergo a sequence of v oltage-dependent ordered interfacial phases that agree with experiment. (C) 2000 Elsevier Science B.V. All rights reserved.