Download or read book Beyond Standard Quantum Chemistry written by Ramón Hernández-Lamoneda and published by . This book was released on 2007-01-01 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book represents an effort to illustrate the breadth and quality of theoretical chemistry research developed at the Universidad Autónoma del Estado de Morelos(UAEMor) in Cuernavaca, México. The reader will find that the contents covered in eight chapters are heterogeneous in their subject matter but, on the other hand, they encompass a wide variety of topics of current research interest in the theoretical chemistry community. The chapters have been ordered from the gas phase, passing to properties of small clusters and liquid solutions, finally leading to solid state studies. The first three chapters deal with small but challenging molecular systems, use of state of the art methodology in their description and a detailed comparison with recent high quality experimental information. Even though the emphasis is on a quantitative description, which challenges contemporary experiments, often new qualitative insights are obtained from these studies which help in the interpretation of previous experimental data and suggest new directions for future work. The next three chapters are devoted to the theoretical description of solvation effects, they go from a microscopic analysis of hydration to an account of the thermodynamical and structural properties of liquid solutions. Starting with detailed studies of protonated water clusters of increasing size, which rely on semiempirical electronic structure calculations, they provide a bridge with the previous chapters, then going to studies of solvation effects for larger solutes using a combination of ab initio based intermolecular potentials together with Monte Carlo simulations as a means to improve models based on the properties of the cavity around the solute and ending with a study of how to improve models that treat the solvent as a continuum by including a microscopic description of the solvent through the use of a lattice around the solute with points of adjustable polarizability. The book closes with two methodologically oriented studies on solid state theoretical chemistry. Both studies illustrate the fact that the development of ab initio methodology and its numerical implementation for the case of crystals is still a very active area of research which borrows some ideas from the more mature molecular electronic structure but has to tackle challenging problems which are inherent to the perfect crystal approach. This is the case in the first study of this section, in which the particular role of space symmetry in the computational implementation of the vibrational analysis in crystalline systems is highlighted. As regards the last chapter, it is devoted to develop a general way to perform variational procedures in crystalline systems in terms of Localized Wannier Functions, which provide a representation alternative to that of the usually considered Bloch Functions. The extension of the Boys localization scheme to periodic systems is used as an illustrating example of the general procedure. We believe that a common ground for all the chapters is the fact that the theoretical tools that are being developed and/or applied to describe a rich variety of chemical systems provide alternatives either in conceptual framework and new qualitative insights, computational efficiency or accuracy in quantitative comparisons with experiment, which go beyond the standard approaches. Most of the contributions include international collaborations which certainly add to the richness and quality of this book and I am sure the local authors will continue to benefit from such collaborations. It is our hope that the current volume will serve as a useful introduction to current research in theoretical chemistry for graduate students and post-doctoral associates but also as a reference for experts coming from the main areas of specialization in this field. The book can also be valuable for experimentalists since several of the book chapters address problems which are being analyzed both by experiment and theory.