When, in my capacity as President of the Societe de Chimie physique, I opened the 24th Annual Meeting of this Society, devoted this year to 'molecular motions in liquids', I was stirred by a particular emotion. This had two reasons, one general and the other rather personal. I would like to give an explanation in the Foreword to this volume of communications to the Meeting and their ensuing discussions. An essential characteristic of science is its international nature. It is like a symphony composed of contributions by all the countries playing together as an orchestra in unison. Just as a melody has different 'colours' when played by strings or woodwinds, so there exist similar 'colour' differences, subtle ones, between scientific contributions from different countries, rooted as they are in their own cultural history and liable to impoverish the ensemble if they should cease to participate. I have always had an impression of marked 'colour' differences prevailing among American, Russian, Japanese and European contributions, although within the latter group the timbre is very much the same. This is why I have dreamed of a European 'chamber orchestra' in addition to the great world orchestra.

A unified overview of the dynamical properties of water and its unique and diverse role in biological and chemical processes.

An essential cross-disciplinary reference for molecular interactions Molecular Theory of Gases and Liquids offers a rigorous, comprehensive treatment of molecular characteristics and behaviors in the gaseous and fluid states. A unique cross-disciplinary approach provides useful insight for students of chemistry, chemical engineering, fluid dynamics, and a variety of related fields, with thorough derivations and in-depth explanations throughout. Appropriate for graduate students and working scientists alike, this book details advanced concepts without sacrificing depth of coverage or technical detail.

This ASI was planned to make a major contribution to the teaching of the principles and methods used in liquid phase ~esearch and to encourage the setting up of collaborative projects, as advocated by the European Molecular Liquids Group (secretary: Dr J. Yarwood, University of Durham, U. K. ). During the past five years considerable progress has been made in studying molecular liquids. The undoubted advantages of international collaboration led to the formation of the European Molecular Liquids Group (EMLG) in July 1981. The activities of the EMLG were widely disseminated in a special session of the European Congress on Molecular Spectroscopy (EUCMOS) held in September 1981 (for details, see J. Mol. Structure, 80 (1982) 375 - 421). Following the success of this meeting, it was thought that the aims and objectives of the E~G would be best served by the organisation of a broader-based gathering designed to attract those interested in the study of the structure, dynamics and interactions in the liquid state. Thanks to the generous support by the Scientific Affairs Division of NATO, it was possible to hold a NATO ASI on Molecular Liquids at the Italian Centre of Stanford University, Florence, Italy during June-July 1983. This book is based on the lectures presented at that meeting. The contents of this volume cover the three broad areas of current liquid phase research: (a) Analytical theory.

Liquid-crystalline phases are now known to be formed by an ever growing range of quite diverse materials, these include those of low molecular weight as well as the novel liquid-crystalline polymers, such phases can also be induced by the addition of a solvent to amphiphilic systems leading to lyotropic liquid crystals. Irrespective of the structure of the constituent molecules these numerous liquid-cl)'Stailine phases are characterised by their long range orientational order. In addition certain phases exhibit elements of long range positional order. Our understanding, both experimental and theoretical, at the molecular level of the static behaviour of these fascinating and important materials is now well advanced. In contrast the influence of the long range order; both orientational and positional, on the molecular dynamics in liquid Cl)'Stais is less well understood. In an attempt to address this situation a NATO Advanced Study Institute devoted to liquid ctystal dynamics was held at n Ciocco, Barga, Italy in September 1989. This brought together experimentalists and theoreticians concerned with the various dynamical processes occurring in all liquid crystals. The skills of the participants was impressively wide ranging; they spanned the experimental techniques used in the study of molecular dynamics, the nature of the systems investigated and the theoretical models employed to understand the results. While much was learnt it was also recognised that much more needed to be done in order to advance our understanding of molecular dynamics in liquid Cl)'Stais.

The activities in this book explain elementary concepts in the study of chemistry, including matter, atoms, molecules, physical properties of matter, and changing states of matter. General background information, suggested activities, questions for discussion, and answers are included. Encourage students to keep completed pages in a folder or notebook for further reference and review.