The electron density of a non-degenerate ground state system determines essentially all physical properties of the system. This statement of the Hohenberg–Kohn theorem of Density Functional Theory plays an exceptionally important role among all the fundamental relations of Molecular Physics. In particular, the electron density distribution and the dynamic properties of this density determine both the local and global reactivities of molecules. High resolution experimental electron densities are increasingly becoming available for more and more molecules, including macromolecules such as proteins. Furthermore, many of the early difficulties with the determination of electron densities in the vicinity of light nuclei have been overcome. These electron densities provide detailed information that gives important insight into the fundamentals of molecular structure and a better understanding of chemical reactions. The results of electron density analysis are used in a variety of applied fields, such as pharmaceutical drug discovery and biotechnology. If the functional form of a molecular electron density is known, then various molecular properties affecting reactivity can be determined by quantum chemical computational techniques or alternative approximate methods.

The growth of technology for chemical assessment has led to great developments in the investigation of chemical reactivity in recent years, but key information is often dispersed across many different research fields. Combining both original principles and the cutting-edge theories used in chemical reactivity analysis, Chemical Reactivity, Volume 1 present the latest developments in theoretical chemistry and its application for the assessment of chemical processes.Beginning with an exploration of different theories and principles relating to electronic structure and reactivity of confined electronic systems, the book goes on to highlight key information on such topics as Dyson orbitals, target-ion overlaps, reaction fragility, magnetizability principles and the Fuki function. Density Functional Theory is discussed in relation to numerous different principles and approaches, with further information on constrained methods and diabatic models, bonding evolution theory, orbital-based population analysis models and charge transfer models, and Quantum chemistry and QTAIM.Consolidating the knowledge of a global team of experts in the field, Chemical Reactivity, Volume 1: Theories and Principles is a useful resource for both students and researchers interested in gaining greater understanding of the principles and theories underpinning chemical reactivity analysis. - Provides readers with the key information needed to gain a good overview of contemporary chemical reactivity studies and a clear understanding of the theory behind state-of-the-art methods in the field - Highlights advances in the computational descriptions of reactivity, including reactivity in confined environments, conceptual density functional theory, and multi-reference quantum chemistry - Provides comprehensive coverage by consolidating the knowledge of many well-known researchers in the field from around the world

In recent years, problems such as environmental and economic crises and pandemics caused by new viruses have been occurring on a global scale. Globalization brings about benefits, but it can increase the potential risks of “systemic problems”, leading to system-wide disruptions. The coronavirus pandemic, declared on March 11, 2020, by the World Health Organization, has revealed social disparities in the form of a higher risk of death for people of low-socioeconomic status and has caused massive destruction of the economy and of globalization itself. Extensive efforts to cope with these challenges have often led to the emergence of additional problems due to the chain of hidden causation. What can be done to protect against such emerging challenges? Despite the resulting complexity, once these individual problems are considered as different aspects of a single whole, seemingly contradictory issues can become totally understandable, as they can be integrated into a single coherent framework. This is the integrationist approach in contrast to the reductionist approach. Situations of this kind are truly relevant to understanding the question, “What are creative complex systems?” This book features contributions by members and colleagues of the Kyoto University International Research Unit of Integrated Complex System Science. It broadens our outlook from the traditional view of stability, in which global situations are eventually stabilized after the impact of destruction, to “creative” complex systems.

This book provides a comprehensive review of seminal as well as recent results in the theory of condensed phases, including liquid metals, quantum liquids and Wigner crystals, along with selected applications, especially in the physical chemistry of molecules and clusters. A large part of this work is dedicated to The Thomasndash;Fermi semiclassical approximation for molecules and condensed phases, and its extension to inhomogeneous electron liquids and liquid metals. Correlation effects in quantum liquids and Wigner crystallization are other areas of focus of this work, with an emphasis towards the effect of low dimensionality and magnetic fields. The volume is a collection of reprints by N H March and collaborators over five decades.

These two volumes collect thirty-eight selected papers from the scientific contributions presented at the Fourth European Workshop on Quantum Systems in Chemistry and Physics (QSCP-IV), held in Marly-le-Roi (France) in April 22-27, 1999, A total ofone hundred and fifteen scientists attended the workshop, 99 from Europe and 16 from the rest ofthe world. They discussed the state of the art, new trends, and future evolution of the methods and applications. The workshop was held in the old town of Marly-le-Roi, which lies to the West of Paris between the historic centres of Saint-Germain-en-Laye and Versailles. Participants were housed at the National Youth Institute, where over sixty lectures were given by l- ding members ofthe scientific community; in addition, over sixty posters were presented in two very animated sessions. We are grateful to the oral speakers and to the poster p- senters for making the workshop such an stimulating experience. The social programme was also memorable - and notjust for the closing banquet, which was held at the French Senate House. We are sure that participants will long remember their visit to the 'Musée des Antiquités Nationales': created by Napoleon III at the birthplace ofLouis XIV, this museum boasts one ofthe world finest collections ofarcheological artifacts. The Marly-le-Roi workshop followed the format established at the three previous meetings, organized by Prof.

Quantum Crystallography is a novel scientific discipline combining quantum chemistry methods and crystal structure determination. The current book describes quantum-mechanical approaches to obtain crystallographic data of enhanced value and explains how they correlate with real diffraction and scattering experiments. In particular, the book covers DFT, Clinton equations, KEM and QTAIM methods and their applications in crystallographic studies.

In the 1970s, Density Functional Theory (DFT) was borrowed from physics and adapted to chemistry by a handful of visionaries. Now chemical DFT is a diverse and rapidly growing field, its progress fueled by numerous developing practical descriptors that make DFT as useful as it is vast. With 34 chapters written by 65 eminent scientists from 13 diffe