This book contains the transcripts of the lectures presented at the NATO Advanced study Institute on "Computational Techniques in Quantum Chemistry and Molecular Physics", held at Ramsau, Germany, 4th - 21st Sept. 1974. Quantum theory was developed in the early decades of this century and was first applied to problems in chemistry and molecular physics as early as 1927. It soon emerged however, that it was impossible to con sider any but the simplest systems in any quantita tive detail because of the complexity of Schrodinger's equation which is the basic equation for chemical and molecular physics applications. This remained the si tuation until the development, after 1950, of elec tronic digital computers. It then became possible to attempt approximate solutions of Schrodinger's equa tion for fairly complicated systems, to yield results which were sufficiently accurate to make comparison with experiment meaningful. Starting in the early nineteen sixties in the United States at a few centres with access to good computers an enormous amount of work went into the development and implementation of schemes for approximate solu tions of Schrodinger's equation, particularly the de velopment of the Hartree-Fock self-consistent-field scheme. But it was soon found that the integrals needed for application of the methods to molecular problems are far from trivial to evaluate and cannot be easily approximated.

This NATO Advanced Study Institute was concerned with modern ab initio methods for the determination of the electronic structure of molecules. Recent years have seen considerable progress in computer technology and computer science and these developments have had a very significant influence on computational molecular physics. Progress in computer technology has led to increasingly larger and faster systems as well as powerful minicomputers. Simultaneous research in computer science has explored new methods for the optimal use of these resources. To a large extent develop ments in computer technology, computer science and computational molecular physics have been mutually dependent. The availability of new computational resources, particularly minicomputers and, more recently, vector processors, has stimulat'ed a great deal of research in molecular physics. Well established techniques have been reformulated to make more efficient use of the new computer technology and algorithms which were previously computationally intractable have now been successfully implemented. This research has given a new and exciting insight into molecular structure and molecular processes by enabling smaller systems to be studied in greater detail and larger systems to be studied for the first time.

An account, from first principles, of the methods of numerical quantum mechanics. Coverage encompasses formulations and fundamental postulates; the Hamiltonian and angular momentum operators; and approximation of the solutions of the Schroedinger equation

This book describes computational methods used in theoretical physics with emphasis on condensed matter applications.

Since 1983 I have been delivering lectures at Budapest University that are mainly attended by chemistry students who have already studied quantum chem istry in the amount required by the (undergraduate) chemistry curriculum of the University, and wish to acquire deeper insight in the field, possibly in prepara tion of a master's or Ph.D. thesis in theoretical chemistry. In such a situation, I have the freedom to discuss, in detail, a limited number of topics which I feel are important for one reason or another. The exact coverage may vary from year to year, but I usually concentrate on the general principles and theorems and other basic theoretical results which I foresee will retain their importance despite the rapid development of quantum chemistry. I commonly organize my lectures by treating the subject from the begin ning, without referring explicitly to any actual previous knowledge in quantum chemistry-only some familiarity with its goals, approaches and, to a lesser ex tent, techniques is supposed. I concentrate on the formulae and their derivation, assuming the audience essentially understands the reasons for deriving these results. This book is basically derived from the material of my lectures. The spe cial feature, distinguishing it from most other textbooks, is that all results are explicitly proved or derived, and the derivations are presented completely, step by step. True understanding of a theoretical result can be achieved only if one has gone through its derivation.

The lecturers as well as the participants came from varied scientific backgrOlUldsfor the NATO -Advanced Study Institute (ASDheld atAltinoluk, Edremit. Turkey during the period of July 31 -August 12 1989. The lecturers were University Professors from the USA, Canada, England, C'-.ermany, France and Spain and they covered a broad spectrwn of specialities from methodology t.o appications. On the other hand students coming from the various NATO countries arrived with an inhomogeneous background to absorb the broad spectnUIl of material covered by the lecturers. However, by the end of the two week period of the ASI, that initial difference in scientific background had been reduced substantially . The lecturers had covered subject matters from the most fundamental to the most applied aspects of theoretical and computational organic chemistry. The lectures were argnmented with tutorial sessions and computational laboratory led by a small group of carefnlly selected tutors. Overall, this NATO -ASI was a ~at success and the Editors are hopeful that the present volume will communicate the scientific success and will radiate the intellectual spirit of the meeting.

First published in 2007, this second edition is for graduate students and researchers in theoretical, computational and experimental physics.

The second edition of Elementary Molecular Quantum Mechanics shows the methods of molecular quantum mechanics for graduate University students of Chemistry and Physics. This readable book teaches in detail the mathematical methods needed to do working applications in molecular quantum mechanics, as a preliminary step before using commercial programmes doing quantum chemistry calculations.This book aims to bridge the gap between the classic Coulson's Valence, where application of wave mechanical principles to valence theory is presented in a fully non-mathematical way, and McWeeny's Methods of Molecular Quantum Mechanics, where recent advances in the application of quantum mechanical methods to molecular problems are presented at a research level in a full mathematical way. Many examples and mathematical points are given as problems at the end of each chapter, with a hint for their solution. Solutions are then worked out in detail in the last section of each Chapter. - Uses clear and simplified examples to demonstrate the methods of molecular quantum mechanics - Simplifies all mathematical formulae for the reader - Provides educational training in basic methodology

REVIEWS IN COMPUTATIONAL CHEMISTRY Kenny B. Lipkowitz, Raima Larter, and Thomas R. Cundari This volume, like those prior to it, features chapters by experts in various fields of computational chemistry. TOPICS COVERED IN Volume 21 iNCLUDE AB INITIO QUANTUM SIMULATION IN SOLID STATE CHEMISTRY; MOLECULAR QUANTUM SIMILARITY; ENUMERATING MOLECULES; VARIABLE SELECTION; BIOMOLECULAR APPLICATIONS OF POISSON-BOLTZMANN METHODS; AND DATA SOURCES AND COMPUTATIONAL APPROACHES FOR GENERATING MODELS OF GENE REGULATORY NETWORKS. FROM REVIEWS OF THE SERIES "Reviews in Computational Chemistry remains the most valuable reference to methods and techniques in computational chemistry." --JOURNAL OF MOLECULAR GRAPHICS AND MODELLING "One cannot generally do better than to try to find an appropriate article in the highly successful Reviews in Computational Chemistry. The basic philosophy of the editors seems to be to help the authors produce chapters that are complete, accurate, clear, and accessible to experimentalists (in particular) and other nonspecialists (in general)." --JOURNAL OF THE AMERICAN CHEMICAL SOCIETY