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.

Inhalt

Les problèmes de l'agitation moléculaire dans les liquides.- Theoretical Aspects of Transport Phenomena.- Viscoelastic and Ultrasonic Relaxation Studies Related to Molecular Motions in Liquids.- On Cluster Expansions and Autocorrelation Functions: Further Remarks on the Divergence of the Density Expansion of Transport Coefficients.- Evidence of Cooperative Phenomena in the Asymptotic Time Behavior of Correlation Functions: Self-Diffusion Coefficient of Methane.- Fully Renormalized Kinetic Theory of Thermal Fluctuations in Liquids.- Isotope Effects Upon Motions in Liquids in the Classical Limit.- Complex Permittivity and Dipole Correlations.- Mouvements orientationnels: Fonctions de corrélation et illustrations expérimentales.- The Influence of the FIR Absorption on the Dielectric Behaviour of Rigid Polar Molecules in Very Dilute Solutions.- Utilisation de la fonction mémoire dans l'interprétation des spectres d'absorption dipolaire des molécules toupies symétriques en phase liquide.- Champ de réaction dynamique en relaxation diélectrique, application au cas du chloroforme à 25°C.- Active Intramolecular Motion In Dielectric Relaxation Of Pure Liquid Diacetyl.- Dielectric Relaxation In Critical Polar Mixtures; Derivation Of Glarum-Cole Equation by Projection Operator Method.- Etude, par relaxation diélectrique, du mouvement brownien des ions dans les liquides simples.- Molecular Vibrations in Liquids.- Détermination par spectrométrie de vibration des fonctions de corrélation orientationnelles monomoléculaires dans les liquides.- Raman Spectroscopy and Molecular Reorientation in Liquids: CDCl3 and CH3Br.- Raman Spectroscopic Studies on Temperature Dependence of Reorientational Motions of CH3J and CD3J Molecules.- Raman Spectroscopic Observation of Collective Excitation of Molecular Vibrations in Liquid Methyl Iodide.- Intermolecular Vibrational Relaxation in Liquids, Measured by the Isotopic Dilution Method.- Mouvements moléculaires du sulfure de carbonyle à l'état dissous par spectrométries Raman et infrarouge.- Vibrational and Reorientational Relaxation of Hydrogen-Bonded Systems.- Vibrational Relaxation in Liquid and Solid Quinoline.- Fonctions de corrélation tensorielles: formalisme général pour les molécules polyatomiques en solution et application au cas de la diffusion du rotateur asymétrique.- The Influence of Vibration-Rotation Coupling on Correlation Functions of Molecules.- Raman Studies of Molecular Reorientation in Liquid Sulfur Hexafluoride.- Etude dynamique par diffusion Raman-laser des hexafluorures de métaux et métalloïdes.- Réorientation de molécules toupie symétrique CH3D et CD3H dissoutes dans des fluides simples du point triple au point critique.- Moments de bandes et fonctions de corrélation rotationnelles en infrarouge pour une vibration perpendiculaire d'une molécule linéaire.- Etude des mouvements moléculaires dans les liquides au moyen du profil des bandes de vibration dans l'infrarouge.- The Temperature Effect on the Width and Intensity of the Raman Spectra.- Etude par spectroscopic infrarouge et par spectroscopic Raman des fluctuations orientationnelles de la molécule de furanne en solution.- Anisotropy in Molecular Reorientational Motions in Simple Liquids.- Translational Motions as Studied by Nuclear Magnetic Resonance.- Nuclear Magnetic Resonance Relaxation Studies of Reorientational Motions in Liquids at High Pressure.- Electron Spin Relaxation in the Study of the Motions of Paramagnetic Probes in Liquids.- Association and Anisotropic Molecular Reorientation in Liquids as Studied by NMR.- Self-Diffusion Measurements in Simple and Complex Liquids.- Study of Molecular Motions in Liquid Methylamines by Nuclear Magnetic Resonance, II.- Investigation of Molecular Liquids by Neutron Spectroscopy.- Comparative Study of Molecular Motion in Liquids by NMR and Neutron Spectroscopy.- Inelastic Neutron Scattering by Chemical Reactions. I: Structure and High Frequency Dynamics of Trifluoroacetic Acids.- Collective Excitations in Liquid Hydrogen Observed by Coherent Neutron Scattering.- Molecular Dynamics: Computer 'Experiments' on Simple Liquids.- Molecular Dynamics Calculation of Neutron Inelastic Scattering from Water.- Computation and Interpretation of the Spectroscopic Properties of Liquids.- Pressure Dependence of the Incoherent Scattering Law and the Time-Dependent Triplet Correlation Function in Dense Hydrogen Gas.- Etude des mouvements moléculaires par diffusion dela lumière.- Etude des mécanismes de relaxation de vibration dans le tétrachlorure de carbone et le chloroforme liquides par analyse des spectres de diffusion Brillouin.- Molecular Motion in Liquids from Low Frequency Depolarized Light Scattering.- Apport des processus de redistribution et de réorientation moléculaire dans les effets électrooptiques non linéaires.- Etude des propriétés viscoélastiques d 'un liquide par diffusion de la lumière.- The Spectrum of Light Scattered from Liquid n-Alkanes.- Brillouin Scattering in the Inert-Gas Liquids: Argon and Krypton.- Rayleigh Scattering: Density Dependence of Orientational Motions in Acetone and Benzene.- Far Infra-Red Absorptions in Non-Dipolar Liquids.- Rototranslational Spectrum of H2 in Liquid A and Comparison Between Intercollisional Interference in Para-H2 and Rare Gases.- Interpretation of Far Infrared Spectra in Terms of a Collision Distribution.- Dielectric Absorption of Non-Polar Liquids in the Microwave and Far Infrared Region.