Electron Correlation in Molecules


Book Description

This text addresses one of theoretical chemistry's central problems. Topics include molecular electronic structure, independent electron models, electron correlation, the linked diagram theorem, and related topics. 1984 edition.




Electron Correlations in Molecules and Solids


Book Description

Dieser Titel verbindet die Festkörpertheorie mit der Quantenchemie. Neue Konzepte der Vielteilchen-Verarbeitung und Korrelations-Effekte, normale quantenchemische Verfahren mit Projektionstechniken, Greensche Funktionen und Monte-Carlo-Methoden werden erarbeitet. Anwendungsbereiche der Molekültheorie, von Halbleitern, supraleitender high-Tc-Materialien, etc., werden vorgestellt.










Explicitly Correlated Wave Functions in Chemistry and Physics


Book Description

Explicitly Correlated Wave Functions in Chemistry and Physics is the first book devoted entirely to explicitly correlated wave functions and their theory and applications in chemistry and molecular and atomic physics. Explicitly correlated wave functions are functions that depend explicitly on interelectronic distance. The book covers a wide range of methods based on explicitly correlated functions written by leaders in the field, including Kutzelnigg, Jeziorski, Szalewicz, Klopper and Noga. The book begins with a chapter on the theory of electron correlation and then the following three chapters describe different types of functions that can be used to solve the electronic Schrödinger equation for atoms and molecules. The book goes on to discuss the effects that go beyond the Born-Oppenheimer approximation, theory of relativistic effects, solution of the Dirac-Colomb equation, and relativistic correction using ECG functions. The last part of the book reviews applications of EC functions to calculate atomic and molecular properties and to study positronic systems, resonance states of atoms and nuclear dynamics of the hydrogen molecular ion.




The Effects of Relativity in Atoms, Molecules, and the Solid State


Book Description

Recent years have seen a growing interest in the effects of relativity in atoms, molecules and solids. On the one hand, this can be seen as result of the growing awareness of the importance of relativity in describing the properties of heavy atoms and systems containing them. This has been fueled by the inadequacy of physical models which either neglect relativity or which treat it as a small perturbation. On the other hand, it is dependent upon the technological developments which have resulted in computers powerful enough to make calculations on heavy atoms and on systems containing heavy atoms meaningful. Vector processing and, more recently, parallel processing techniques are playing an increasingly vital role in rendering the algorithms which arise in relativistic studies tractable. This has been exemplified in atomic structure theory, where the dominant role of the central nuclear charge simplifies the problem enough to permit some prediction to be made with high precision, especially for the highly ionized atoms of importance in plasma physics and in laser confinement studies. Today's sophisticated physical models of the atom derived from quantum electrodynamics would be intractable without recourse to modern computational machinery. Relativistic atomic structure calculations have a history dating from the early attempts of Swirles in the mid 1930's but continue to provide one of the primary test beds of modern theoretical physics.




Atom - Molecule Collision Theory


Book Description

The broad field of molecular collisions is one of considerable current interest, one in which there is a great deal of research activity, both experi mental and theoretical. This is probably because elastic, inelastic, and reactive intermolecular collisions are of central importance in many of the fundamental processes of chemistry and physics. One small area of this field, namely atom-molecule collisions, is now beginning to be "understood" from first principles. Although the more general subject of the collisions of polyatomic molecules is of great im portance and intrinsic interest, it is still too complex from the viewpoint of theoretical understanding. However, for atoms and simple molecules the essential theory is well developed, and computational methods are sufficiently advanced that calculations can now be favorably compared with experimental results. This "coming together" of the subject (and, incidentally, of physicists and chemists !), though still in an early stage, signals that the time is ripe for an appraisal and review of the theoretical basis of atom-molecule collisions. It is especially important for the experimentalist in the field to have a working knowledge of the theory and computational methods required to describe the experimentally observable behavior of the system. By now many of the alternative theoretical approaches and computational procedures have been tested and intercompared. More-or-Iess optimal methods for dealing with each aspect are emerging. In many cases working equations, even schematic algorithms, have been developed, with assumptions and caveats delineated.




Atomic, Molecular, and Optical Physics


Book Description

The goals of atomic, molecular, and optical physics (AMO physics) are to elucidate the fundamental laws of physics, to understand the structure of matter and how matter evolves at the atomic and molecular levels, to understand light in all its manifestations, and to create new techniques and devices. AMO physics provides theoretical and experimental methods and essential data to neighboring areas of science such as chemistry, astrophysics, condensed-matter physics, plasma physics, surface science, biology, and medicine. It contributes to the national security system and to the nation's programs in fusion, directed energy, and materials research. Lasers and advanced technologies such as optical processing and laser isotope separation have been made possible by discoveries in AMO physics, and the research underlies new industries such as fiber-optics communications and laser-assisted manufacturing. These developments are expected to help the nation to maintain its industrial competitiveness and its military strength in the years to come. This report describes the field, characterizes recent advances, and identifies current frontiers of research.




Advances in Chemical Physics, Volume 14


Book Description

The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.




Applications of Topological Methods in Molecular Chemistry


Book Description

This is the first edited volume that features two important frameworks, Hückel and quantum chemical topological analyses. The contributors, which include an array of academics of international distinction, describe recent applications of such topological methods to various fields and topics that provide the reader with the current state-of-the-art and give a flavour of the wide range of their potentialities.