High-throughput screening and combinatorial chemistry are two of the most potent weapons ever to have been used in the discovery of new drugs. At a stroke, it seems to be possible to synthesise more molecules in a month than have previously been made in the whole of the distinguished history of organic chemistry, Furthermore, all the molecules can be screened in the same short period. However, like any weapons of immense power, these techniques must be used with care, to achieve maximum impact. The costs of implementing and running high-throughput screening and combinatorial chemistry are high, as large dedicated facilities must be built and staffed. In addition, the sheer number of chemical leads generated may overwhelm the lead optimisation teams in a hail of friendly fire. Mother nature has not entirely surrendered, as the number of building blocks that could be used to build libraries would require more atoms than there are in the universe. In addition, the progress made by the Human Genome Project has uncovered many proteins with different functions but related binding sites, creating issues of selectivity. Advances in the new field of pharmacogenomics will produce more of these challenges. There is a real need to make hi- throughput screening and combinatorial chemistry into 'smart' weapons, so that their power is not dissipated. That is the challenge for modellers, computational chemists, cheminformaticians and IT experts. In this book, we have broken down this grand challenge into key tasks.

In this book, a novel optimization method inspired by a paradigm from nature is introduced. The chemical reactions are used as a paradigm to propose an optimization method that simulates these natural processes. The proposed algorithm is described in detail and then a set of typical complex benchmark functions is used to evaluate the performance of the algorithm. Simulation results show that the proposed optimization algorithm can outperform other methods in a set of benchmark functions.

This chemical reaction optimization paradigm is also applied to solve the tracking problem for the dynamic model of a unicycle mobile robot by integrating a kinematic and a torque controller based on fuzzy logic theory. Computer simulations are presented confirming that this optimization paradigm is able to outperform other optimization techniques applied to this particular robot application.

Hydrogen Bonding New Insights is an extensive text which takes numerous examples from experimental studies and uses these to illustrate theoretical investigations to allow a greater understanding of hydrogen bonding phenomenon. The most important topics in recent studies are considered including:

Intra-molecular H-bonds

Differences between H-bond and van der Waals interactions from one side and covalent bonds from the other

Bader theory to analyze H-bonding

Influence of weak H-bonds upon structure and function of biological molecules

H-bonds in crystal structures

With contributions from some of the foremost experts in this field this volume provides an invaluable resource for all members of the academic community looking for a comprehensive text on hydrogen bonding. It will be of particular interest to physical and theoretical chemists, spectroscopists, crystallographers and those involved with chemical physics."

This volume develops multiscale and multiphysics simulation methods to understand nano- and bio-systems by overcoming the limitations of time- and length-scales. Here the key issue is to extend current computational simulation methods to be useful for providing microscopic understanding of complex experimental systems. This thesis discusses the multiscale simulation approaches in nanoscale metal-insulator-metal junction, molecular memory, ionic transport in zeolite systems, dynamics of biomolecules such as lipids, and model lung system. Based on the cases discussed here, the author suggests various systematic strategies to overcome the limitations in time- and length-scales of the traditional monoscale approaches.

1. R.G. Pearson Chemical Hardness - An Historical Introduction 2. P.K. Chattaraj Density Functional Theory of Chemical Hardness 3. J.L. Gazqu z Hardness and Softness in Density Functional Theory 4. L. Komorowski Hardness Indices for Free and Bonded Atoms 5. N.H. March The Ground-State Energy of Atomic and Molecular Ions and Its Variation with the Number of Elections 6. K. Sen Isoelectronic Changes in energy, Electronegativity, and Hardness in Atoms via the Calculations of 7. P. Politzer, J.S. Murray, M.E. Grice Charge Capacities and Shell Structures of Atoms 8. R. F. Nalewajski The Hardness Based Molecular Charge Sensitivities and Their Use in the Theory of Chemical Reactivity 9. B.G. Baekelandt, R. A. Schoonheydt, W.J. Mortier The EEM Approach to Chemical Hardness in Molecules and Solids: Fundamentals and Applications 10. J.A. Alonso, L. C. Balbas Hardness of Metallic Clusters

1. G. Engelhardt, H. Koller, Stuttgart, FRG: 29Si NMR of Inorganic Solids 2. H. Pfeifer, Leizpig, FRG: NMR of Solid Surfaces 3. A. Sebald, Bayreuth, FRG: MAS and CP/MAS NMR of Less Common Spin-1/2 Nuclei 4. C. J{ger, Mainz, FRG: Satellite Transition Spectroscopy of Quadrupolar Nuclei 5. D. Brinkmann, M. Mali, Z}rich, CH: NMR-NQR Studies of High-Temperature Superconductors

Over the past decade high performance computing has demonstrated the ability to model and predict accurately a wide range of physical properties and phenomena. Many of these have had an important impact in contributing to wealth creation and improving the quality of life through the development of new products and processes with greater efficacy, efficiency or reduced harmful side effects, and in contributing to our ability to understand and describe the world around us. Following a survey ofthe U.K.'s urgent need for a supercomputingfacility for aca demic research (see next chapter), a 256-processor T3D system from Cray Research Inc. went into operation at the University of Edinburgh in the summer of 1994. The High Performance Computing Initiative, HPCI, was established in November 1994 to support and ensure the efficient and effective exploitation of the T3D (and future gen erations of HPC systems) by a number of consortia working in the "frontier" areas of computational research. The Cray T3D, now comprising 512 processors and total of 32 CB memory, represented a very significant increase in computing power, allowing simulations to move forward on a number offronts. The three-fold aims of the HPCI may be summarised as follows; (1) to seek and maintain a world class position incomputational scienceand engineering, (2) to support and promote exploitation of HPC in industry, commerce and business, and (3) to support education and training in HPC and its application.

"A Structural and Vibrational Investigation into Chromyl Azide, Acetate, Perchlorate and Thiocyanate Compounds" reviews the structural and vibrational properties of chromyl azide, acetate, perchlorate, and thiocyanate from a theoretical point of view by using Density Functional Theory (DFT) methods. These compounds are extensively used in organic syntheses and the study of their structure and spectroscopy has become fundamental.
This book evaluates the best theoretical level and basis set to reproduce the experimental data existing for those compounds. To this end, the optimized geometries and wavenumbers for the normal modes of vibration are calculated and the obtained results are compared and analyzed. Also, the nature of the different types of bonds and their corresponding topological properties of electronic charge density are systematically and quantitatively investigated by using the NBO analysis and the atoms in molecules theory (AIM).

A summary of all the most important aspects of supramolecular science, from molecular recognition in chemical and biological systems to supramolecular devices, materials and catalysis. The 17 chapters cover calixarenes, catenanes, cavitands, cholophanes, dendrimers, membranes and self-assembly systems, molecular modelling, molecular level devices, organic materials, peptides and protein surfaces, recognition of carbohydrates, rotaxanes, supramolecular catalysis. A forward-looking chapter written by J.-M. Lehn indicated the future prospects for the entire field. Audience: Ph.D. students and young researchers in chemistry, physics and biology.

From the beginnings of modern chemistry, molecular structure has been a lively area of research and speculation. For more than half a century spectroscopy and other methods have been available to characterize the structures and shapes of molecules, particularly those that are rigid. However, most molecules are at least to some degree non-rigid and this non-rigidity plays an important role in such diverse areas as biological activity, energy transfer, and chemical reactivity. In addition, the large-amplitude vibrations present in non-rigid molecules give rise to unusual low-energy vibrational level patterns which have a dramatic effect on the thermodynamic properties of these systems. Only in recent years has a coherent picture of the energetics and dynamics of the conformational changes inherent in non-rigid (and semi-rigid) molecules begun to emerge. Advances have been made in a number of different experimental areas: vibrational (infrared and Raman) spectroscopy, rotational (microwave) spectroscopy, electron diffraction, and, most recently, laser techniques probing both the ground and excited electronic states. Theoretically, the proliferation of powerful computers coupled with scientific insight has allowed both empirical and ab initio methods to increase our understanding of the forces responsible for the structures and energies of non-rigid systems. The development of theory (group theoretical methods and potential energy surfaces) to understand the unique characteristics of the spectra of these floppy molecules has also been necessary to reach our present level of understanding. The thirty chapters in this volume contributed by the key speakers at the Workshop are divided over the various areas. Both vibrational and rotational spectroscopy have been effective at determining the potential energy surfaces for non-rigid molecules, often in a complementary manner. Recent laser fluorescence work has extended these types of studies to electronic excited states. Electronic diffraction methods provide radial distribution functions from which both molecular structures and compositions of conformational mixtures can be found. Ab initio calculations have progressed substantially over the past few years, and, when carried out at a sufficiently high level, can accurately reproduce (or predict ahead of time) experimental findings. Much of the controversy of the ARW related to the question of when an ab initio is reliable. Since the computer programs are readily available, many poor calculations have been carried out. However, excellent results can be obtained from computations when properly done. A similar situation exists for experimental analyses. The complexities of non-rigid molecules are many, but major strides have been taken to understand their structures and conformational processes.

The ideas of probability are all around us. Lotteries, casino gambling, the al most non-stop polling which seems to mold public policy more and more these are a few of the areas where principles of probability impinge in a direct way on the lives and fortunes of the general public. At a more re moved level there is modern science which uses probability and its offshoots like statistics and the theory of random processes to build mathematical descriptions of the real world. In fact, twentieth-century physics, in embrac ing quantum mechanics, has a world view that is at its core probabilistic in nature, contrary to the deterministic one of classical physics. In addition to all this muscular evidence of the importance of probability ideas it should also be said that probability can be lots of fun. It is a subject where you can start thinking about amusing, interesting, and often difficult problems with very little mathematical background. In this book, I wanted to introduce a reader with at least a fairly decent mathematical background in elementary algebra to this world of probabil ity, to the way of thinking typical of probability, and the kinds of problems to which probability can be applied. I have used examples from a wide variety of fields to motivate the discussion of concepts."

"Kinetics and Dynamics" on molecular modeling of dynamic processes opens with an introductory overview before discussing approaches to reactivity of small systems in the gas phase. Then it examines studies of systems of increasing complexity up to the dynamics of DNA. This title has interdisciplinary character presenting wherever possible an interplay between the theory and the experiment. It provides basic information as well as the details of theory and examples of its application to experimentalists and theoreticians interested in modeling of dynamic processes in chemical and biochemical systems. All contributing authors are renowned experts in their fields and topics covered in this volume represent the forefront of today's science.

Both molecular spectroscopy and computational chemistry have witnessed rapid significant progresses in recent years. On the one hand, it is nowadays possible to compute, to quite a reasonable degree of accuracy, almost all fundamental spectroscopic properties for small molecular systems. The theoretical approach is now properly considered to be of fundamental importance in attaining a high degree of understanding of spectroscopic information. Moreover, it may be also a great help in designing and planning experiments. On the other hand, new and very powerful experimental techniques have been developed. This book combines an advanced teaching standpoint with an emphasis on the interplay between theoretical and experimental molecular spectroscopy. It covers a wide range of topics (such as molecular dynamics and reactivity, conformational analysis, hydrogen bonding and solvent effects, spectroscopy of excited states, complex spectra interpretation and simulation, software development and biochemical applications of molecular spectroscopy) and considers a large variety of molecular spectroscopic techniques, either from an experimental or from a theoretical perspective. (short text) This book combines an advanced teaching standpoint with an emphasis on the interplay between theoretical and experimental molecular spectroscopy. It covers a wide range of topics (such as molecular dynamics and reactivity, conformational analysis, hydrogen bonding and solvent effects, spectroscopy of excited states, complex spectra interpretation and simulation, software development and biochemical applications of molecular spectroscopy) and considers a large variety of molecular spectroscopic techniques either from an experimental or from a theoretical perspective.

The theoretical chemist is accustomed to judging the success of a theoretical prediction according to how well it agrees with an experimental measurement. Since the object of theory is the prediction of the results of experiment, that would appear to be an entirely satisfactory state ofaffairs. However, ifit is true that "the underlying physicallaws ...for the whole ofchemistryare ...completely known" (1), thenit shouldbepossible,atleastinprinciple, topredict theresults of experiment moreaccurately than they canbe measured. Ifthe theoreticalchemist could obtain exact solutions ofthe Schrodinger equation for many-body systems, then the experimental chemist would soon become accustomed to judging the success ofan experimental measurement by how well it agrees with a theoretical prediction. In fact, it is now possible to obtainexact solutions ofthe Schrodinger equation for systems ofa few electrons(2-8). These systems include the molecular ion Ht, the molecule H , the reaction intermediate H-H-H, the unstable pair H-He, the 2 stable dimer He2' and the trimer He3. The quantum Monte Carlo method used in solving the time-independent Schrodinger equation for these systems is exact in that it requires no physical or mathematical assumptions beyond those of the Schrodinger equation. As in most Monte Carlo methods there is a statistical or sampling error which is readily estimated.

Foldable Flex and Thinned Silicon Multichip Packaging Technology presents newly emerging methods used to make stacked chip packages in the so-called 2-1/2 D technology (3-D in physical format, but interconnected only through the circuits on folded flex). It is also being used in single chip packages where the thinness of the chips and the flex substrate made packages significantly thinner than through any other means.

This book introduces the concept of crystallographic non- rigidity and asymmetry of the transition elements as central atoms organometallic compounds. This intrinsic behavior of central atoms in condensed matter is quantified by applying statistical approach. Averaging of extrinsic factors in crystal structures is tested by using variance analysis. Introductionof the above mentioned concept and applications of variance analysis as an approximation for considering factors influencing properties of central atomin the crystal is original and new.

Criteria of orbital symmetry conservation had a profound influence on mechanistic thinking in organic chemistry and are still commonly applied today. The author presents a coherent set of operational rules for the analysis of scope and reliability. It is written from the viewpoint of Orbital Correspondence Analysis in Maximum Symmetry (OCAMS). Its advantage lies in its provision of a coherent overview of the relation between symmetry and mechanism. For reasons of consistency, the book remains within the framework of molecular orbital theory.

"Imagination and shrewd guesswork are powerful instruments for acquiring scientific knowledge . . . " 1. H. van't Hoff The last decades have witnessed a rapid growth of quantum chemistry and a tremendous increase in the number of very accurate ab initio calculations of the electronic structure of molecules yielding results of admirable accuracy. This dramatic progress has opened a new stage in the quantum mechanical description of matter at the molecular level. In the first place, highly accurate results provide severe tests of the quantum mecha nics. Secondly, modern quantitative computational ab initio methods can be synergetically combined with various experimen tal techniques thus enabling precise numerical characterization of molecular properties better than ever anticipated earlier. However, the role of theory is not exhausted in disclosing the fundamental laws of Nature and production of ever increasing sets of data of high accuracy. It has to provide additionally a means of systematization, recognition of regularities, and ratio nalization of the myriads of established facts avoiding in this way complete chaos. Additional problems are represented by molecular wavefunctions provided by the modern high-level computational quantum chemistry methods. They involve, in principle, all the information on molecular system, but they are so immensely complex that can not be immediately understood in simple and physically meaningful terms. Both of these aspects, categorization and interpretation, call for conceptual models which should be preferably pictorial, transparent, intuitively appealing and well-founded, being sometimes useful for semi quantitative purposes."

The focus of this thesis is the computational modelling of transition metal bimetallic (nanoalloy) clusters. More specifically, the study of Pd-Pt, Ag-Pt, Au-Au and Pd-Au as a few tens of atoms in the gas phase. The author used a combination of global optimization techniques - coupled with a Gupta-type empirical many-body potential - and Density Functional Theory (DFT) calculations to study the structures, bonding and chemical ordering, as well as investigate the chemisorptions of hydrogen and carbon monoxide on bimetallic clusters. This research is highly relevant to experimental catalytic studies and has resulted in more than seven publications in international journals.