Im Jahr 1937 erschienen die ersten Lehrbucher des damals noch sehr jungen Fachgebiets der Quantenchemie, beide geschrieben von Hans Hellmann (1903-1938). Im Gegensatz zu anderen fruhen Werken zu diesem und nah verwandten Fachgebieten, wie den Buchern von Pauling & Wilson (1935) oder von Eyring, Walter & Kimball (1944), wurden Hellmanns Lehrbucher spater weder nachgedruckt noch neu aufgelegt. Beachtet man seine bedeutenden wissenschaftlichen Leistungen - erwahnt seien hier die Aufklarung der Natur der kovalenten chemischen Bindung (1933), das molekulare Virialtheorem (1933), das quantenmechanische Krafttheorem (1933, 1936/1937, heute als Hellmann-Feynman-Theorem bekannt), die Pseudopotentialmethode (1934) und die spater von Born und Huang erneut und weiter bearbeitete Theorie der diabatischen und adiabatischen Elementarreaktionen (1935) -, so kann dieser Sachverhalt nur unzureichend durch Hellmanns tragisches Schicksal erklart werden. Eine Neuauflage der deutschen Fassung von Hellmanns Lehrbuch ist daher mehr als wunschenswert.

Die Theoretische Chemie hat eine zweihundert Jahre alte Tradition in der Chemie. Zu Anfang des 19. Jahrhunderts, als die Chemie sich als eigenstandige Wissenschaft zu etablieren begann, erschienen ein- oder mehrbandige Werke zur Theoretischen Chemie. Das vorliegende Werk basiert auf einem Genealogie-Projekt des Autors, stellt gewissermassen ein Who is who der Theoretischen Chemie dar und beschreibt ihre Entwicklung in Deutschland in den letzten 200 Jahren.

The weak or non-conventional hydrogen bond has been the subject of intense scrutiny over recent years. Now available in paperback, this highly acclaimed book provides a critical assessment on this interesting and occasionally controverstial interaction type.

Theoretical chemistry has been an area of tremendous expansion and development over the past decade; from an approach where we were able to treat only a few atoms quantum mechanically or make fairly crude molecular dynamics simulations, into a discipline with an accuracy and predictive power that has rendered it an essential complementary tool to experiment in basically all areas of science.
This volume gives a flavour of the types of problems in biochemistry that theoretical calculations can solve at present, and illustrates the tremendous predictive power these approaches possess.
A wide range of computational approaches, from classical MD and Monte Carlo methods, via semi-empirical and DFT approaches on isolated model systems, to Car-Parinello QM-MD and novel hybrid QM/MM studies are covered. The systems investigated also cover a broad range; from membrane-bound proteins to various types of enzymatic reactions as well as inhibitor studies, cofactor properties, solvent effects, transcription and radiation damage to DNA.

The second edition of an established graduate text, this book complements the material for a typical advanced graduate course in quantum mechanics by showing how the underlying classical structure is reflected in quantum mechanical interference and tunnelling phenomena, and in the energy and angular momentum distributions of quantum mechanical states in the moderate to large (10-100) quantum number regime. Applications include accurate quantization techniques for a variety of tunnelling and curve-crossing problems and of non-separable bound systems; direct inversion of molecular scattering and spectroscopic data; wavepacket propagation techniques; and the prediction and interpretation of elastic, inelastic and chemically reactive scattering. The main text concentrates less on the mathematical foundations than on the global influence of the classical phase space structures on the quantum mechanical observables. Further mathematical detail is contained in the appendices and worked problem sets are included as an aid to the student.

The latest developments in quantum and classical molecular dynamics, related techniques, and their applications to several fields of science and engineering. Molecular simulations include a broad range of methodologies such as Monte Carlo, Brownian dynamics, lattice dynamics, and molecular dynamics (MD).

Features of this book:

- Presents advances in methodologies, introduces quantum methods and lists new techniques for classical MD

- Deals with complex systems: biomolecules, aqueous solutions, ice and clathrates, liquid crystals, polymers

- Provides chemical reactions, interfaces, catalysis, surface phenomena and solids

Although the book is not formally divided into methods and applications, the chapters are arranged starting with those that discuss new algorithms, methods and techniques, followed by several important applications.

Considers that Napoleon's 1812 Russian campaign may have failed because cold temperatures caused his army's tin buttons to disintegrate, identifying other important moments and traditions in history that were influenced by molecular properties. Reprint. 25,000 first printing.

The chemist's approach to the understanding of matter and its chemical transformations is to take a microscopic view, connecting experimental observation with the properties of the consitutent molecules. Atoms and subatomic particles do not obey the classical laws of mechanics but conform rather to the laws of quantum mechanics. Quantum mechanics is thus of central importance in chemistry. In order to understand the behaviour of molecules and their constituent particles it is necessary to have a thorough grounding in the principles and applications of quantum mechanics.

Understanding the factors which determine the rates and products of elementary reactions is of fundamental importance to chemists. This informative book contains a concise introductory account of the theoretical framework and experimental methods used to elucidate the detailed mechanism of gas phase elementary reactions.

Die Berechnung der Konstanten der potentiellen Energie der MolekiUe ist eines der Hauptprobleme in der Auswertung der Molekiilspektren ((0:32), S. 28, (0:21), S. 59). Diese Konstanten der potentiellen Energie bzw. Kraftkonstanten der Molekille ermoglichen die Gewinnung von Aussagen iiber jede einzelne Bindung im Molekill, wie dies neben der quantentheoretischen Methode nur noch wenige Methoden fUr vielatomige Molekiile gestatten (7:6). Damit stellt die Kraftkonstantenrechnung ein Hilfsmittel zur Kliirung bindungstheoretischer Strukturfragen chemischer Verbindungen dar. Die experimentellen Grof3en oder Observablen stellen die Schwingungs- frequenzen der Molekiile dar, wie sie mit Ultrarot-und Raman-Spektren-Ge- raten gewonnen werden, die in der sog. Spektralmatrix zusammengefa t wer- den. Weiterhin gehen in die Rechnung noch die Valenzwinkel, die Gleichge- wichtsabstande und die Massen ein, die in der Matrix der kinetischen Energie zusammengefa t werden. Die Berechnung der Matrix der Konstanten der potentiellen Energie erfolgt klassisch nach der Theorie der kleinen Schwingungen, wobei das Molektil als ein mechanisches Punktsystem angesehen wird, dessen klassische Schwingungsfre- quenzen mit den quantentheoretischen Strahlungsfrequenzen flir den Dbergang zwischen Grundzustand und dem ersten angeregten Schwingungszustand des Molekills gleichgesetzt werden kann ((0:27), S. 168). Auch fUr die quantentheoretische Theorie der moglichen EnergiezusUinde von Molekiilen stellen die klassischen Schwingungsfrequenzen die entscheidenden Parameter dar ((0:27), S. 168, (0: 1 06), S. 49).

To understand matter and its chemical transformations it is necessary to take a microscopic view, however, at this microscopic level atoms and sub-atomic particles do not obey the classical laws of mechanics that pertain to the everyday macroscopic world. They obey the laws of quantum mechanics.

The aim of this book is to explain the fundamentals of quantum mechanics from the point of view of chemistry; to describe areas of chemistry where quantum mechanics is most important; and to show how quantum mechanics is applied to chemical problems. To this end, the book is divided into two parts: the first deals with the foundations of quantum mechanics, and the second is a tool kit for applying quantum mechanics to chemical problems.

Although advanced mathematics has been kept to a minimum, the nature of the subject means a certain amount of mathematics is necessary and it is assumed readers will be familiar with a typical first year mathematics course.

This textbook is intended for undergraduate and graduate students pursuing courses in chemistry and allied fields. It includes fundamental concepts, equations involved in organic reactions, chemical bonds (ionic and covalent bonds), hybridization, representation of a chemical reaction and mechanism of organic reactions. The book also discusses the displacement of bonding electrons involving inductive effect, electromeric effect, mesomeric effect, hyperconjugative effect and resonance. A number of organic reactions involving formation of intermediates such as carbocations, carbanions, free radicals, carbenes, nitrenes and benzynes have also been included. It also discusses different types of reagents involved in a chemical reactions along with types of additional reactions and its detailed mechanism. The book also includes the use of pedagogical elements such as multiple choice questions and end of chapter exercises to aid self-learning among students

This book provides the reader with a unified understanding of the rapidly expanding field of molecular materials and devices: electronic structures and bonding, magnetic, electrical and photo-physical properties, and the mastering of electrons in molecular electronics. This revised edition includes updates and additions on hot topics such as molecular spintronics (the role of spin in electron transport) and molecular machines (how electrons can generate molecular motions). Chemists will discover how to understand the relations between electronic structures and properties of molecular entities and assemblies, and to design new molecules and materials. Physicists and engineers will realize how the molecular world fits in with their need for systems flexible enough to check theories or provide original solutions to exciting new scientific and technological challenges. The non-specialist will find out how molecules behave in electronics at the most minute, sub-nanosize level.

This Primer presents an introduction to molecular symmetry and point groups with an emphasis on their applications. The author has adopted a non-mathematical approach as far as possible. The text is based on a successful course given by the author.

The present status of Density Functional Theory (DFT), which has evolved as the main technique for the study of matter at the atomistic level, is described in this volume. Knowing the behavior of atoms and molecules provides a sure avenue for the design of new materials with specific features and properties in many areas of science and technology. A technique based on purely first principles allowing large savings in time and money greatly benefits the specialist or designer of new materials.

The range of areas where DFT is applied has expanded and continues to do so. Any area where a molecular system is the center of attention can be studied using DFT.The scope of the 22 chapters in this book amply testifies to this.

Mit diesem Buch erfullt sich der Autor einen langgehegten Wunsch, die Prinzipien und Grundlagen der Wellenmechanik (Quantenmechanik) in der Anwendung auf die Materie und ihre Bausteine einem breiten Leserkreis zuganglich zu machen. Der Autor ist der Meinung, dass nur dieses Wissen und die damit verbundenen Konsequenzen die notwendigen Voraussetzungen dafur sind, sinnvoll und effektiv uber Fragen der menschlichen Existenz und uber menschliches Verhalten nachzudenken. Die Folgerungen aus diesem Wissen beeinflussen daher unmittelbar auch alle Bereiche menschlicher Einsicht und fuhren zu bindenden Lebensprinzipien, die damit letzen Endes aus den wellenmechanischen Erkenntnissen resultieren. Das Buch beginnt fast voraussetzungslos und der Autor spricht den Leser immer wieder unmittelbar in einem lockeren Stil an, um ihm auf diese Weise Mut gebend den Weg in diese letzlich komplexe und ungewohnliche Mikrowelt zu ebnen."

All chemistry students need a basic understanding of quantum theory and its applications in atomic and molecular structure and spectroscopy. This book provides a gentle introduction to the subject with the required background in physics and mathematics kept to a minimum. It develops the basic concepts needed as background. The emphasis throughout is on the physical concepts and their application in chemistry, especially to atoms and to the periodic table of elements

The first introductory text of its kind, this inexpensive primer will provide first and second year students in chemistry, physics, and biochemistry with a clear, accessible introduction to the electronic structure and quantised energy levels in atoms and molecules. Lecturers have long been seeking a text which will lay the foundations for students taking a first course in spectroscopic methods, and this Primer provides a perfect supplement to core texts, which do not cover the subject adequately.

Die modernen Entwicklungen der Theorie der CRT werden beschrieben und umfangreich dokumentiert. Fur die praktische Anwendung werden diese Modelle eingeordnet und bewertet. Die Modelle der Katalyse und Diffusionsphanomene werden detailliert behandelt, insbesondere in poroesen Medien (Zeolithen, Clays, Nanotubes). Moderne theoretische Methoden wie Molekulardynamik, Monte Carlo- und Quantenchemie werden dargestellt. Adsorption und Desorption in der Katalyse werden sowohl theoretisch als auch experimentell eingehend beschrieben. Zusatzlich wird sehr umfassend die vorhandene Literatur behandelt und bewertet. Damit ist das Buch eine sehr umfassende Darstellung des Status quo, zur Einarbeitung und als UEbersicht fur Ingenieure und Wissenschaftler in Forschung, Entwicklung und Lehre, in Chemie, chemischer Technik/Verfahrenstechnik und angrenzenden Gebieten.

Nuclear magnetic resonsance (NMR) spectrocopy is the most powerful research tool used in chemistry today, but many chemists have yet to realize its true potential. Recent advances in NMR have led to a formidable array of new techniques - and acronyms - which leaves even the professional spectroscopist bewildered. How, then, can chemists decide which approach will solve their particular structural or mechanistic problem?

This book provides a non-mathematical, descriptive approach to modern NMR spectroscopy, taking examples from organic, inorganic, and biological chemistry. It also contains much practical advice about the acquisition and use of spectra. Starting from the simple 'one pulse' sequence, the text employs a 'building block' approach to lead naturally to multiple pulse and two-dimensional NMR. Spectra of readily available compounds illustrate each technique. One- and two- dimensional methods are integrated in three chapters which show how to solve problems by making connections between spins through bonds, through space, or through exchange. There are also chapters on spectrum editing and solids. The final chapter contains a case history which attempts to weave the many strands of the text into a coherent strategy.

This second edition reflects the progress made by NMR in the past few years; there is a greater emphasis on inorganic nuclei; some two-colour spectra are used; the treatment of heteronuclear experiments has moved from direct to 'inverse' detection; many new examples and spectra have been included; and the literature to early 1992 has been covered.

An accompanying text, Modern NMR spectroscopy: A workbook of chemical problems, by Jeremy Sanders, Edwin Constable, and Brian Hunter, is available from OUP. Using a combination of worked examples and set problems, this workbook provides a practical guide to the accurate interpretation of NMR spectra, which will be of value to students and professional scientists alike.

Systeme aus Elektronen und Atomkemen sind sehr komplexe Systeme. Das mag zuerst verwundem, da zwischen den Teilchen reine Coulomb-Wechsel- wirkungen vorliegen, man vergiBt aber oft dabei, daB ein wei teres - bisher unverstandenes - Naturgesetz (das Pauli-Prinzip) zu der Moglichkeit un- endlich verschiedener Strukturen filhren kann, von denen viele mit hoher Wahrscheinlichkeit in der Natur verwirklicht werden und ineinander tiber- gehen konnen, wenn es die makroskopischen Verhliltnisse und bestimmte Symmetrievoraussetzungen zulassen, die mit dem Spin der Teilchen zusam- menhiingen. Wegen der Kleinheit der Teilchen ist ihr Verhalten akausal und kann nur durch Wahrscheinlichkeitsaussagen (Wellenmechanik) beschrieben wer- den. Aufgabe der Theoretischen Chemie ist es also, die Verstiindnislehre der Chemie in diesem Sinne zu formulieren und anzuwenden. Man kann daher durchaus feststellen, daB insbesondere die Chemie, aber auch Teile der Biochemie, Astrophysik oder Pharmazie (urn einige zu nen- nen) die Lehre vom Verhalten von Elektronen und Atomkemen darstellen, und daB dadurch sinnvollerweise unter Theoretischer Chemie alle physi- kalischen Aspekte der o.g. Bereiche (insbesondere die Physikalische Che- mie) subsumiert werden mtissen, soweit sie sich unmittelbar theoretisch oder halbtheoretisch mit der chemischen Materie beschiiftigen, ohne jedoch nliher auf die inneren Strukturen der Atomkeme einzugehen (Kemphysik). Die Chemie beweist tiberzeugend, wie komplex und unerwartet (filr die Nicht-Theoretiker) sich chemische Materie, also Systeme aus Elektronen und Atomkemen verhalten konnen.

This book addresses the move towards quantum communications, in light of the recent technological developments on photonic crystals and their potential applications in systems. The authors present the state of the art on extensive quantum communications, the first part of the book being dedicated to the relevant theory; quantum gates such as Deutsch gates, Toffoli gates and Dedekind gates are reviewed with regards to their feasibility as electronic circuits and their implementation in systems, and a comparison is performed in parallel with conventional circuits such as FPGAs and DSPs. The specifics of quantum communication are also revealed through the entanglement and Bell states, and mathematical and physical aspects of quantum optical fibers and photonic crystals are considered in order to optimize the quantum transmissions. These concepts are linked with relevant, practical examples in the second part of the book, which presents six integrated applications for quantum communications.

This book explains the observed trends in the bonding and structure of molecules and solids within the models of the electronic structure. Emphasis is placed throughout on recent theoretical developments that link structural stability to the local topology or connectivity of the lattice through the moments of the electronic density of states. The chemically-intuitive Tight Binding approximation provides a unified treatment of the covalent bond in small molecules and extended solids, while the physically-intuitive Nearly-Free Electron approximation provides a natural description of the metallic bonds in sp-valent metals. Unlike the conventional reciprocal-space formulation of band theory, this modern real-space approach allows an immediate understanding of the origin of structural trends within the periodic table for the elements and the AB structure map for binary compounds. Although this unique book is aimed primarily at postgraduates in physics, chemistry, and materials science, a chapter on basic quantum mechanical concepts is included for those readers with little or no basic knowledge of the subject.

Personal Computer (PC) werden immer h{ufiger als "Arbeitsplatzcomputer" auchin technischen Bereichen eingesetzt. Ihre Verwendung in Labor, Versuchs- undPr}ffeld st|~t jedoch auf Schwierigkeiten oder f}hrt gar zu Fehlschl{gen, weil M|glichkeiten und Grenzen dieser Ger{te falsch eingesch{tzt werden, weil die Anpassung an den technischen Proze~ unzureichend ist oder die Programmierung des Rechners unzweckm{~ig. Hiersetzt das Buch an, vermittelt Grundlagen, zeigt Wege und Beispiele auf, wie bislang "von Hand" nur unvollst{ndig oder m}hsam zu bew{ltigende Me~aufgabenmit Hilfe eines PC erfolgreich, effizient und "richtiger" gel|st werden k|nnen. Ziel des Buches ist es, dem Leser Entscheidungshilfen zur Auswahl geeigneter Personalcomputer, von Peripherie-Hardware und Software an die Hand zu geben und ihm wichtige Voraussetzungen mitzugeben, um die vielf{ltigen Eigenschaften von Personalcomputern wirkungsvoll zu nutzen und Me~probleme souver{n bearbeiten zu k|nnen.

The new edition of this established workbook consists of worked examples and set problems that cover one- and two-dimensional NMR techniques applied to organic and inorganic systems. Most of the problems are genuine research examples, and this new edition contains eight pages of problems drawn from very recent research work. This second edition is fully compatible with the second edition of the highly successful Modern NMR Spectroscopy: a guide for chemists, and the two books are thoroughly cross referenced throughout.