Advances In Quantum Chemical Topology Beyond Qtaim

Advances in Quantum Chemical Topology Beyond QTAIM provides a complete overview of the field, starting with traditional methods and then covering key steps to the latest state-of-the-art extensions of QTAIM. The book supports researchers by compiling and reviewing key methods, comparing different algorithms, and providing computational results to show the efficacy of the approaches. Beginning with an introduction to quantum chemistry, QTAIM and key extensions, the book goes on to discuss interacting quantum atoms and related energy properties, explores partitioning methods, and compares algorithms for QTAIM. Partitioning schemes are them compared in more detail before applications are explored and future developments discussed. Drawing together the knowledge of key authorities in the area, this book provides a comprehensive, pedogeological guide to this insightful theory for all those interested in modelling, exploring and understanding molecular properties. Provides a contemporary review of the extensions and application of QTAIM methods Compiles all extensions of QTAIM in one place for easy reference Includes a chapter with an Introduction to Quantum Chemistry Presents complex information at a level accessible to those engaged in theoretical/computational chemistry

This book begins by providing a simplified version of the computational quantum chemistry sufficient to calculate the wavefunctions that are the basic input of NG-QTAIM. Enough basic (scalar) QTAIM theory is provided to understand the later chapters. In addition, our developments of scalar QTAIM are presented and activities at various levels of difficulty are provided for the readership to facilitate understanding. The topological origins of Quantum Theory of Atoms in Molecules (QTAIM) before explaining the highlights and consequences of the developments of Next-Generation QTAIM (NG-QTAIM) that is a 3-D vector-based realization of QTAIM. The book compiles all developments and extensions of Next-Generation QTAIM in one place for easy reference for those engaged in theoretical/computational chemistry. Essential insights into molecular switch functioning not available from the energy barrier or any scalar measures are presented along with a new measure to assess the efficiency of rotary molecular motors. The book also discusses how the treatment of external forces such as electric fields and laser irradiation is included in NG-QTAIM. This book benefits theoretical/computational chemists/physics/engineers, students (graduate and undergraduate) and chemical/pharmaceutical industry researchers who carry out chemical computations in universities and industries. Where appropriate, Target Learning Outcomes and Further Reading are provided along with a list of the scientific goals to be addressed in addition to a glossary table in the summary sections. Where applicable each chapter concludes by outlining benefits, limitations and suggestions for further investigations. All our NG-QTAIM publications are available as pre-prints in the form of .pdf files along with the corresponding supplementary materials at our BEACON website www.beaconresearch.org.

Advances in Quantum Chemistry publishes articles and invited reviews by leading international researchers in quantum chemistry. Quantum chemistry deals particularly with the electronic structure of atoms, molecules, and crystalline matter and describes it in terms of electron wave patterns. It uses physical and chemical insight, sophisticated mathematics and high-speed computers to solve the wave equations and achieve its results. Advances highlights these important, interdisciplinary developments.

Advances in the Theory of Atomic and Molecular Systems, is a collection of contributions presenting recent theoretical and computational developments that provide new insights into the structure, properties, and behavior of a variety of atomic and molecular systems. This volume (subtitled: Conceptual and Computational Advances in Quantum Chemistry) focuses on electronic structure theory and its foundations. This volume is an invaluable resource for faculty, graduate students, and researchers interested in theoretical and computational chemistry and physics, physical chemistry and chemical physics, molecular spectroscopy, and related areas of science and engineering.

Advances in Quantum Chemistry

Chemical bond stands as the alpha-and-omega of Chemistry: it is at the beginning because, according with International Union of Pure and Applied Chemistry-IUPAC, a bond exists between two atoms or groups of atoms when the forces acting between them lead to an aggregation with sufficient stability to be considered as molecular species; it is also at the end due its mysterious way of acting through electronic behavior that is comparable with nothing of the observed world. The fact that two electrons, which in principle repel each other as they approach, can exist in a certain molecular space providing the atoms-in-molecule binding - that is still an unfolded reality. Nevertheless, quantum theory had furnished the main analytical tools with which the so called ordinary chemistry reduced at the many-electronic problem, a field equally belonging to quantum physics and quantum chemistry. After the impressive success of quantum theory in explaining atomic structure and spectra starting from the complete analytical solution of Hydrogen atom, and after the further quantum extensions of models to include the elucidation of simple molecules, the Chemistry arrives today in front of new challenges: nano- and bio-systems. At this point it seems that there is no chance to provide fully analytical results with the myriads of electrons in macro-molecules. Moreover, even one could admit that the computational techniques will evolve sufficient to deliver numerical results these will certainly suffer of opacity in interpretation loosing the most beloved issue of chemists: the intuition. At the same time, there are also relatively small molecules with particular bonding features, since bonds in which there are no shared electrons between atoms - at one extreme - or molecules with a sextuple bond - at other extreme - may be identified. As a consequence, the increased need of molecular design for assessing nano- and bio- targets through active ligands, the practical demands of predictions of acute toxicity in medicine and ecotoxicology - all these actual realities of chemistry in its principles and applications, call for dedicated reviews. In such theoretically demanded context of conceptual and computational chemistry the present review book likes to give a survey of the quantum physical chemistry and of its application in chemical bond and bonding description. Through the chapters of this book ones of the leading scientists in both physical and chemical fields have gave their valuable contributions for decrypting the actual status quo of the chemical bond and bonding: from self-consistent equations of many-electronic systems, localization, and reactivity principles, to coherent electronic states, to non-covalent bonding and overlapping concepts, to hydrogen and biomolecular bonding, to molecular connectivity and topological indices, to oscillatory quantum states of molecules, to carbon and pseudohalide bonding, to three-center bonding problem, to biochemistry, to medicine, and to ecotoxicology chemical bonding implications. It is therefore a comprehensive volume of physical and chemical quantum approaches of molecules grasping various conceptual and computational levels. It is also an invitation to reflect upon the possibility of unifying the physical and chemical quantum concepts in a novel alchemy of molecular structure. In this respect worth, finally, recalling that the author of Philosophia Naturalis Principia Mathematica was, at his time, proudly considered himself merely as an alchemist, and that his corpuscular vision about light was based on revealed concept of sympathy . From sympathy to bond and bonding it appears that the actual Chemistry and Physics continue to offer fascinating mysteries to humankind of which the elucidation of the nature of the chemical bond being, perhaps, the greatest one.

An introduction to the rapidly evolving methodology of electronic excited states For academic researchers, postdocs, graduate and undergraduate students, Quantum Chemistry and Dynamics of Excited States: Methods and Applications reports the most updated and accurate theoretical techniques to treat electronic excited states. From methods to deal with stationary calculations through time-dependent simulations of molecular systems, this book serves as a guide for beginners in the field and knowledge seekers alike. Taking into account the most recent theory developments and representative applications, it also covers the often-overlooked gap between theoretical and computational chemistry. An excellent reference for both researchers and students, Excited States provides essential knowledge on quantum chemistry, an in-depth overview of the latest developments, and theoretical techniques around the properties and nonadiabatic dynamics of chemical systems. Readers will learn: ● Essential theoretical techniques to describe the properties and dynamics of chemical systems ● Electronic Structure methods for stationary calculations ● Methods for electronic excited states from both a quantum chemical and time-dependent point of view ● A breakdown of the most recent developments in the past 30 years For those searching for a better understanding of excited states as they relate to chemistry, biochemistry, industrial chemistry, and beyond, Quantum Chemistry and Dynamics of Excited States provides a solid education in the necessary foundations and important theories of excited states in photochemistry and ultrafast phenomena.

This book distills the knowledge gained from research into atoms in molecules over the last 10 years into a unique, handy reference. Throughout, the authors address a wide audience, such that this volume may equally be used as a textbook without compromising its research-oriented character. Clearly structured, the text begins with advances in theory before moving on to theoretical studies of chemical bonding and reactivity. There follow separate sections on solid state and surfaces as well as experimental electron densities, before finishing with applications in biological sciences and drug-design. The result is a must-have for physicochemists, chemists, physicists, spectroscopists and materials scientists.