to arrive at some temporary consensus model or models; and to present reliable physical data pertaining to water under a range of conditions, i.e., "Dorsey revisited," albeit on a less ambitious scale. I should like to acknowledge a debt of gratitude to several of my col leagues, to Prof. D. J. G. Ives and Prof. Robert L. Kay for valuable guidance and active encouragement, to the contributors to this volume for their willing cooperation, and to my wife and daughters for the understanding shown to a husband and father who hid in his study for many an evening. My very special thanks go to Mrs. Joyce Johnson, who did all the cor respondence and much of the arduous editorial work with her usual cheerful efficiency. F. FRANKS Biophysics Division Unilever Research Laboratory ColworthjWelwyn Colworth House, Sharnbrook, Bedford March 1972 Contents Chapter 1 Introduction-Water, the Unique Chemical F. Franks I. lntroduction ........................................ . 2. The Occurrence and Distribution of Water on the Earth 2 3. Water and Life ...................................... 4 4. The Scientific Study of Water-A Short History ........ 8 5. The Place of Water among Liquids . . . . . . . . . . . . . . . 13 . . . . . Chapter 2 The Water Moleeule C. W. Kern and M. Karplus 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 . . . . . . . . . . 2. Principles of Structure and Spectra: The Born-Oppenheimer Separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 . . . . . . . . . . . . 3. The Electronic Motion ............................... 26 3.1. The Ground Electronic State of Water ............ 31 3.2. The Excited Electronic States of Water ........... 50 4. The Nuclear Motion ................................. 52 5. External-Field Effects ................................. 70 5.1. Perturbed Hartree-Fock Method . . . . . . . . . . . . . . . 74 . . .

This Volume, the last of the series, is devoted to water in its metastable forms, especially at sub-zero temperatures. The past few years have wit nessed an increasing interest in supercooled water and amorphous ice. If the properties of liquid water in the normal temperature range are already eccentric, then they become exceedingly so below the normal freezing point, in the metastable temperature range. Water can be supercooled to -39°C without too much effort, and most of its physical properties show a re markable temperature dependence under these conditions. Although ade quate explanations are still lacking, the time has come to review available knowledge. The study of amorphous ice, that is, the solid formed when water vapor is condensed on a very cold surface, is of longer standing. It has achieved renewed interest because it may serve as a model for the liquid state. There is currently a debate whether or not a close structural relation ship exists between amorphous ice and supercooled water. The nucleation and growth of ice in supercooled water and aqueous solutions is also still one of those grey areas of research, although these topics have received considerable attention from chemists and physicists over the past two decades. Even now, the relationships between degree of supercooling, nucleation kinetics, crystal growth kinetics, cooling rate and solute concentration are somewhat obscure. Nevertheless, at the empirical level much progress has been made, because these topics are of considerable importance to biologists, technologists, atmospheric physicists and gla ciologists.

For many processes and applications in science and technology a basic knowledge of liquids and solutions is a must. Gaining a better understanding of the behavior and properties of pure liquids and solutions will help to improve many processes and to advance research in many different areas. This book provides a comprehensive, self-contained and integrated survey of this topic and is a must-have for many chemists, chemical engineers and material scientists, ranging from newcomers in the field to more experienced researchers. The author offers a clear, well-structured didactic approach and provides an overview of the most important types of liquids and solutions. Special topics include chemical reactions, surfaces and phase transitions. Suitable both for introductory as well as intermediate level as more advanced parts are clearly marked. Includes also problems and solutions.

The study of liquids covers a wide range of scientific disciplines, primarily in physics and chemistry. As a result of this disparate activity the links between new developments in remote fields are seldom co-ordinated into a single conference. The objective of the present meeting was to gather together people with different forms of expertise. Previous ASI meetings on the liquid state have been held over an extended period and have occurred on a three-yearly basis. The first meeting in this series was on 'Structure and Dynamics of Liquids' in 1980 and was held on the island of Corsica. The next meeting on 'Molecular liquids: Dynamics and Interactions' was held in Florence in 1983 and was followed by 'Aqueous Solutions' at the Institut d'Etudes Scientifiques de Cargese in 1986. It therefore seemed a natural choice to select Cargese for the next meeting in 1989 and to choose a topic which emphasised a particular area of liquid state studies. Due to our own involvement in collaborative research we considered that 'Hydrogen-bonded liquids' would be an appropriate topic. One of its attractions, was that there was much new material coming from widely disparate investigations and it would be a convenient time to draw together the different strands. The particular interest in water was clearly central to this topic but it was thought desirable to set this development in the wider context of other systems in which hydrogen-bonding plays a significant role.

Basic Concepts: Composition, Structure, and State. First and Second Laws of Thermodynamics. Transfer Processes. Thermodynamics of Water. Nucleation and Diffusional Growth. Moist Thermodynamics Processes in the Atmosphere. Static Stability of the Atmosphere and Ocean. Cloud Characteristics and Processes. Ocean Surface Exchanges of Heat and Freshwater. Sea, Ice, Snow, and Glaciers. Thermohaline Processes in the Ocean. Special Topics: Global Energy and Entropy Balances. Thermodynamics Feedbacks in the Climate System. Planetary Atmospheres and Surface Ice. Appendices. Subject Index.

Hypersaline Brines and Evaporitic Environments