I feel very honored that I have been asked to write a Foreword to this book. The subject of the book - "Coupled cluster theory" - has been around for about half a century. The basic theory and explicit equations for closed-shell ground states were formulated before 1970. At the beginning of the seventies the rst ab initio calcu- tion were carried out. At that time speed and memory of computers were very limited compared to today's standards. Moreover, the size of one-electron bases employed was small, so that it was only possible to achieve an orientation in methodical aspects rather than to generate new signi cant results. Extensive use of the coupled-cluster method started at the beginning of the eighties. With the help of more powerful computers the results of coupled-cluster approaches started to yield more and more interesting results of relevance to the interpretation of experimental data. New ideas in methodology kept appearing and computer codes became more and more ef cient. This exciting situation continues to this very day. Remarkably enough, even the - quired equations can now be generated by a computer with the help of symbolic languages. The size of this monograph and the rich variety of articles it contains attests to the usefulness and viability of the couple-cluster formalism for the h- dling of many-electron correlation effects. This represents a vivid testimony of a tremendous work that has been accomplished in coupled-cluster methodology and its exploitation.
The coupled cluster method represents one of the most successful and often used approaches to a quantum-theoretical determination of atomic, molecular, and solid state electronic structure and properties. These methods are relevant to a broad spectrum of disciplines ranging from astrophysics to pharmacology.
The knowledge of various chemical and physical properties (such as dipole or quadrupole moments, ionization potentials or electron affinities, excitation energies, polarizabilities and hyperpolarizabilities, potential energy and property surfaces, etc.) is essential for an understanding of many basic processes and, ultimately, for the development and design of practical devices and techniques based on such phenomena. The key to all such computations is the efficient and size-extensive handling of many-electron correlation effects, which represents a particularly strong aspect of coupled cluster methods.
Recent Progress in Coupled Cluster Methods provides an excellent overview of status quo and future trends in coupled cluster methodology which will enable both researchers and students to become acquainted with recent progress in this area of continuing intense activity. Each of the 22 chapters has been prepared by eminent practitioners in this field of endeavor and emphasizes the fundamental aspects as well as related methodology.
This volume provides a useful source of reference for both researchers in chemistry, molecular physics and molecular biology and practitioners working in these fields. It is also recommendable to people using related software packages.
