As materials research focuses into finding ways to control the growth of atomic scale structures, there is correspondingly increasing emphasis on to the problem of surface diffusion. Clearly surface diffusion is the key process, which determines how atoms move on the surface. Controlling this motion can lead to the easy fabrication of well-controlled nanostructures broadening the present possibilities in nanotechnology. The paradigm of surface diffusion has outgrown its standard textbook description as a random walk on a rigid substrate. In real systems for more complex situations are encountered: interacting atoms are commonly present on the surface with their motions highly correlated, different phases form on the surface with different dynamics, large concentration gradients drive the system far away from the linear response regime, rich metastable structures form as a result of balanced interplay between different kinetic processes, substrate relaxation can change the energy landscape and the diffusion barriers, etc. The motivation behind this ARW was to bring together the international community working on these problems. We felt that the large number of researchers, new results, and well-formulated open questions in this area require some form of integration in a single forum. The ARW and the upcoming proceedings book with papers by the majority of the participants has provided this forum. The meeting was not planned as a continuation of the earlier NATO ASI in Rhodes in 1996, although several people have participated in both meetings.

The interest in the problem of surface diffusion has been steadily growing over the last fifteen years. This is clearly evident from the increase in the number of papers dealing with the problem, the development of new experimental techniques, and the specialized sessions focusing on diffusion in national and international meetings. Part of the driving force behind this increasing activity is our recently acquired ability to observe and possibly control atomic scale phenomena. It is now possible to look selectively at individual atomistic processes and to determine their relative importance during growth and reactions at surfaces. The number of researchers interested in this problem also has been growing steadily which generates the need for a good reference source to farniliarize newcomers to the problem. While the recent emphasis is on the role of diffusion during growth, there is also continuing progress on the more traditional aspects of the problem describing mass transport in an ensemble of particles. Such a description is based on the statistical mechanical analysis of a collection of particles that mutually interact and develop correlations. An average over the multitude of atomistic processes that operate under these conditions is necessary to fully describe the dynamics in the system.

This book provides a comprehensive account of the modern theory for the dynamical properties of polymer solutions. The theory has undergone dramatic evolution over the last two decades due to the introduction of new methods and concepts that have extended the frontier of theory from dilute solutions in which polymers move independently to concentrated solutions where many polymers converge. Among the properties examined are viscoelasticity, diffusion, dynamic light scattering, and electric birefringence. Nonlinear viscoelasticity is discussed in detail on the basis of molecular dynamical models. The book bridges the gap between classical theory and new developments, creating a consistent picture of polymer solution dynamics over the entire concentration range.