Molecular Electronic-Structure Theory

Download Molecular Electronic-Structure Theory PDF Online Free

Author :
Publisher : John Wiley & Sons
ISBN 13 : 1119019559
Total Pages : 949 pages
Book Rating : 4.1/5 (19 download)

DOWNLOAD NOW!


Book Synopsis Molecular Electronic-Structure Theory by : Trygve Helgaker

Download or read book Molecular Electronic-Structure Theory written by Trygve Helgaker and published by John Wiley & Sons. This book was released on 2014-08-11 with total page 949 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ab initio quantum chemistry has emerged as an important tool in chemical research and is appliced to a wide variety of problems in chemistry and molecular physics. Recent developments of computational methods have enabled previously intractable chemical problems to be solved using rigorous quantum-mechanical methods. This is the first comprehensive, up-to-date and technical work to cover all the important aspects of modern molecular electronic-structure theory. Topics covered in the book include: * Second quantization with spin adaptation * Gaussian basis sets and molecular-integral evaluation * Hartree-Fock theory * Configuration-interaction and multi-configurational self-consistent theory * Coupled-cluster theory for ground and excited states * Perturbation theory for single- and multi-configurational states * Linear-scaling techniques and the fast multipole method * Explicity correlated wave functions * Basis-set convergence and extrapolation * Calibration and benchmarking of computational methods, with applications to moelcular equilibrium structure, atomization energies and reaction enthalpies. Molecular Electronic-Structure Theory makes extensive use of numerical examples, designed to illustrate the strengths and weaknesses of each method treated. In addition, statements about the usefulness and deficiencies of the various methods are supported by actual examples, not just model calculations. Problems and exercises are provided at the end of each chapter, complete with hints and solutions. This book is a must for researchers in the field of quantum chemistry as well as for nonspecialists who wish to acquire a thorough understanding of ab initio molecular electronic-structure theory and its applications to problems in chemistry and physics. It is also highly recommended for the teaching of graduates and advanced undergraduates.

Quantum Chemistry

Download Quantum Chemistry PDF Online Free

Author :
Publisher : Courier Corporation
ISBN 13 : 0486151417
Total Pages : 176 pages
Book Rating : 4.4/5 (861 download)

DOWNLOAD NOW!


Book Synopsis Quantum Chemistry by : Henry F. Schaefer III

Download or read book Quantum Chemistry written by Henry F. Schaefer III and published by Courier Corporation. This book was released on 2012-11-14 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: For each of 150 landmark papers in ab initio molecular electronic structure methods, the author provides a lucid commentary that focuses on methodology, rather than particular chemical problems. 1984 edition.

Molecular Electronic-structure Theory

Download Molecular Electronic-structure Theory PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (969 download)

DOWNLOAD NOW!


Book Synopsis Molecular Electronic-structure Theory by : Trygve Helgaker

Download or read book Molecular Electronic-structure Theory written by Trygve Helgaker and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Modern Electronic Structure Theory

Download Modern Electronic Structure Theory PDF Online Free

Author :
Publisher : World Scientific
ISBN 13 : 9789810229870
Total Pages : 772 pages
Book Rating : 4.2/5 (298 download)

DOWNLOAD NOW!


Book Synopsis Modern Electronic Structure Theory by : David Yarkony

Download or read book Modern Electronic Structure Theory written by David Yarkony and published by World Scientific. This book was released on 1995 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern Electronic Structure Theory provides a didactically oriented description of the latest computational techniques in electronic structure theory and their impact in several areas of chemistry. The book is aimed at first year graduate students or college seniors considering graduate study in computational chemistry, or researchers who wish to acquire a wider knowledge of this field.

Advanced Theories and Computational Approaches to the Electronic Structure of Molecules

Download Advanced Theories and Computational Approaches to the Electronic Structure of Molecules PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 940096451X
Total Pages : 241 pages
Book Rating : 4.4/5 (9 download)

DOWNLOAD NOW!


Book Synopsis Advanced Theories and Computational Approaches to the Electronic Structure of Molecules by : C.E. Dykstra

Download or read book Advanced Theories and Computational Approaches to the Electronic Structure of Molecules written by C.E. Dykstra and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: That there have been remarkable advances in the field of molecular electronic structure during the last decade is clear not only to those working in the field but also to anyone else who has used quantum chemical results to guide their own investiga tions. The progress in calculating the electronic structures of molecules has occurred through the truly ingenious theoretical and methodological developments that have made computationally tractable the underlying physics of electron distributions around a collection of nuclei. At the same time there has been consider able benefit from the great advances in computer technology. The growing sophistication, declining costs and increasing accessibi lity of computers have let theorists apply their methods to prob lems in virtually all areas of molecular science. Consequently, each year witnesses calculations on larger molecules than in the year before and calculations with greater accuracy and more com plete information on molecular properties. We can surely anticipate continued methodological develop ments of real consequence, and we can also see that the advance in computational capability is not about to slow down. The recent introduction of array processors, mUltiple processors and vector machines has yielded a tremendous acceleration of many types of computation, including operations typically performed in quantum chemical studies. Utilizing such new computing power to the ut most has required some new ideas and some reformulations of existing methods.

Quantum Chemistry

Download Quantum Chemistry PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 128 pages
Book Rating : 4.:/5 (872 download)

DOWNLOAD NOW!


Book Synopsis Quantum Chemistry by : Henry F. Schaefer

Download or read book Quantum Chemistry written by Henry F. Schaefer and published by . This book was released on 1984 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

State of The Art of Molecular Electronic Structure Computations: Correlation Methods, Basis Sets and More

Download State of The Art of Molecular Electronic Structure Computations: Correlation Methods, Basis Sets and More PDF Online Free

Author :
Publisher : Academic Press
ISBN 13 : 0128161752
Total Pages : 360 pages
Book Rating : 4.1/5 (281 download)

DOWNLOAD NOW!


Book Synopsis State of The Art of Molecular Electronic Structure Computations: Correlation Methods, Basis Sets and More by :

Download or read book State of The Art of Molecular Electronic Structure Computations: Correlation Methods, Basis Sets and More written by and published by Academic Press. This book was released on 2019-09-07 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: State of the Art of Molecular Electronic Structure Computations: Correlation Methods, Basis Sets and More, Volume 79 in the Advances in Quantum Chemistry series, presents surveys of current topics in this rapidly developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry and biology. Chapters in this new release include Computing accurate molecular properties in real space using multiresolution analysis, Self-consistent electron-nucleus cusp correction for molecular orbitals, Correlated methods for computational spectroscopy, Potential energy curves for the NaH molecule and its cation with the cock space coupled cluster method, and much more. Presents surveys of current topics in this rapidly-developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry and biology Features detailed reviews written by leading international researchers

Perspectives in Electronic Structure Theory

Download Perspectives in Electronic Structure Theory PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 3642201806
Total Pages : 727 pages
Book Rating : 4.6/5 (422 download)

DOWNLOAD NOW!


Book Synopsis Perspectives in Electronic Structure Theory by : Roman F. Nalewajski

Download or read book Perspectives in Electronic Structure Theory written by Roman F. Nalewajski and published by Springer Science & Business Media. This book was released on 2012-03-23 with total page 727 pages. Available in PDF, EPUB and Kindle. Book excerpt: The understanding in science implies insights from several different points of view. Alternative modern outlooks on electronic structure of atoms and molecules, all rooted in quantum mechanics, are presented in a single text. Together these complementary perspectives provide a deeper understanding of the localization of electrons and bonds, the origins of chemical interaction and reactivity behavior, the interaction between the geometric and electronic structure of molecules, etc. In the opening two parts the basic principles and techniques of the contemporary computational and conceptual quantum chemistry are presented, within both the wave-function and electron-density theories. This background material is followed by a discussion of chemical concepts, including stages of the bond-formation processes, chemical valence and bond-multiplicity indices, the hardness/softness descriptors of molecules and reactants, and general chemical reactivity/stability principles. The insights from Information Theory, the basic elements of which are briefly introduced, including the entropic origins and Orbital Communication Theory of the chemical bond, are the subject of Part IV. The importance of the non-additive (interference) information tools in exploring patterns of chemical bonds and their covalent and ionic components will be emphasized.

Modern Electronic Structure Theory

Download Modern Electronic Structure Theory PDF Online Free

Author :
Publisher : World Scientific
ISBN 13 : 9812832114
Total Pages : 785 pages
Book Rating : 4.8/5 (128 download)

DOWNLOAD NOW!


Book Synopsis Modern Electronic Structure Theory by : D. R. Yarkony

Download or read book Modern Electronic Structure Theory written by D. R. Yarkony and published by World Scientific. This book was released on 1995 with total page 785 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern Electronic Structure Theory provides a didactically oriented description of the latest computational techniques in electronic structure theory and their impact in several areas of chemistry. The book is aimed at first year graduate students or college seniors considering graduate study in computational chemistry, or researchers who wish to acquire a wider knowledge of this field.

Advances in molecular electronic structure theory

Download Advances in molecular electronic structure theory PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (18 download)

DOWNLOAD NOW!


Book Synopsis Advances in molecular electronic structure theory by :

Download or read book Advances in molecular electronic structure theory written by and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Advances in Molecular Electronic Structure Theory

Download Advances in Molecular Electronic Structure Theory PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (9 download)

DOWNLOAD NOW!


Book Synopsis Advances in Molecular Electronic Structure Theory by :

Download or read book Advances in Molecular Electronic Structure Theory written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

A New Dimension to Quantum Chemistry

Download A New Dimension to Quantum Chemistry PDF Online Free

Author :
Publisher : Oxford University Press, USA
ISBN 13 :
Total Pages : 500 pages
Book Rating : 4.3/5 (91 download)

DOWNLOAD NOW!


Book Synopsis A New Dimension to Quantum Chemistry by : Yukio Yamaguchi

Download or read book A New Dimension to Quantum Chemistry written by Yukio Yamaguchi and published by Oxford University Press, USA. This book was released on 1994 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: In modern theoretical chemistry, the importance of the analytic evaluation of energy derivatives from reliable wave functions can hardly be overestimated. This monograph presents the formulation and implementation of analytical energy derivative methods in ab initio quantum chemistry. It includes a systematic presentation of the necessary algebraic formulae for all of the derivations. The coverage is limited to derivative methods for wave functions based on the variational principle, namely restricted Hartree-Fock (RHF), configuration interaction (CI) and multi-configuration self-consistent-field (MCSCF) wave functions. The monograph is intended to facilitate the work of quantum chemists, and will serve as a useful resource for graduate-level students of the field.

Proceedings of MEST 2012: Exponential Type Orbitals for Molecular Electronic Structure Theory

Download Proceedings of MEST 2012: Exponential Type Orbitals for Molecular Electronic Structure Theory PDF Online Free

Author :
Publisher : Academic Press
ISBN 13 : 0124115594
Total Pages : 311 pages
Book Rating : 4.1/5 (241 download)

DOWNLOAD NOW!


Book Synopsis Proceedings of MEST 2012: Exponential Type Orbitals for Molecular Electronic Structure Theory by :

Download or read book Proceedings of MEST 2012: Exponential Type Orbitals for Molecular Electronic Structure Theory written by and published by Academic Press. This book was released on 2013-11-19 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Quantum Chemistry presents surveys of current topics in this rapidly developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry, and biology. It features detailed reviews written by leading international researchers. This volume focuses on the theory of heavy ion physics in medicine. Advances in Quantum Chemistry presents surveys of current topics in this rapidly developing field and this volume focuses on the theory of heavy ion physics in medicine

Molecular Electronics

Download Molecular Electronics PDF Online Free

Author :
Publisher : World Scientific
ISBN 13 : 9814282596
Total Pages : 724 pages
Book Rating : 4.8/5 (142 download)

DOWNLOAD NOW!


Book Synopsis Molecular Electronics by : Juan Carlos Cuevas

Download or read book Molecular Electronics written by Juan Carlos Cuevas and published by World Scientific. This book was released on 2010 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1. The birth of molecular electronics. 1.1. Why molecular electronics?. 1.2. A brief history of molecular electronics. 1.3. Scope and structure of the book -- 2. Fabrication of metallic atomic-size contacts. 2.1. Introduction. 2.2. Techniques involving the scanning electron microscope (STM). 2.3. Methods using atomic force microscopes (AFM). 2.4. Contacts between macroscopic wires. 2.5. Transmission electron microscope. 2.6. Mechanically controllable break-junctions (MCBJ). 2.7. Electromigration technique. 2.8. Electrochemical methods. 2.9. Recent developments. 2.10. Electronic transport measurements. 2.11. Exercises -- 3. Contacting single molecules: Experimental techniques. 3.1. Introduction. 3.2. Molecules for molecular electronics. 3.3. Deposition of molecules. 3.4. Contacting single molecules. 3.5. Contacting molecular ensembles. 3.6. Exercises -- 4. The scattering approach to phase-coherent transport in nanocontacts. 4.1. Introduction. 4.2. From mesoscopic conductors to atomic-scale junctions. 4.3. Conductance is transmission : heuristic derivation of the Landauer formula. 4.4. Penetration of a potential barrier : tunnel effect. 4.5. The scattering matrix. 4.6. Multichannel Landauer formula. 4.7. Shot noise. 4.8. Thermal transport and thermoelectric phenomena. 4.9. Limitations of the scattering approach. 4.10. Exercises -- 5. Introduction to Green's function techniques for systems in equilibrium. 5.1. The Schrodinger and Heisenberg pictures. 5.2. Green's functions of a noninteracting electron system. 5.3. Application to tight-binding Hamiltonians. 5.4. Green's functions in time domain. 5.5. Exercises -- 6. Green's functions and Feynman diagrams. 6.1. The interaction picture. 6.2. The time-evolution operator. 6.3. Perturbative expansion of causal Green's functions. 6.4. Wick's theorem. 6.5. Feynman diagrams. 6.6. Feynman diagrams in energy space. 6.7. Electronic self-energy and Dyson's equation. 6.8. Self-consistent diagrammatic theory : the Hartree-Fock approximation. 6.9. The Anderson model and the Kondo effect. 6.10. Final remarks. 6.11. Exercises -- 7. Nonequilibrium Green's functions formalism. 7.1. The Keldysh formalism. 7.2. Diagrammatic expansion in the Keldysh formalism. 7.3. Basic relations and equations in the Keldysh formalism. 7.4. Application of Keldysh formalism to simple transport problems. 7.5. Exercises -- 8. Formulas of the electrical current : exploiting the Keldysh formalism. 8.1. Elastic current : microscopic derivation of the Landauer formula. 8.2. Current through an interacting atomic-scale junction. 8.3. Time-dependent transport in nanoscale junctions. 8.4. Exercises -- 9. Electronic structure I: Tight-binding approach. 9.1. Basics of the tight-binding approach. 9.2. The extended Huckel method. 9.3. Matrix elements in solid state approaches. 9.4. Slater-Koster two-center approximation. 9.5. Some illustrative examples. 9.6. The NRL tight-binding method. 9.7. The tight-binding approach in molecular electronics. 9.8. Exercises -- 10. Electronic structure II : density functional theory. 10.1. Elementary quantum mechanics. 10.2. Early density functional theories. 10.3. The Hohenberg-Kohn theorems. 10.4. The Kohn-Sham approach. 10.5. The exchange-correlation functionals. 10.6. The basic machinery of DFT. 10.7. DFT performance. 10.8. DFT in molecular electronics. 10.9. Exercises -- 11. The conductance of a single atom. 11.1. Landauer approach to conductance: brief reminder. 11.2. Conductance of atomic-scale contacts. 11.3. Conductance histograms. 11.4. Determining the conduction channels. 11.5. The chemical nature of the conduction channels of oneatom contacts. 11.6. Some further issues. 11.7. Conductance fluctuations. 11.8. Atomic chains : parity oscillations in the conductance. 11.9. Concluding remarks. 11.10. Exercises -- 12. Spin-dependent transport in ferromagnetic atomic contacts. 12.1. Conductance of ferromagnetic atomic contacts. 12.2. Magnetoresistance of ferromagnetic atomic contacts. 12.3. Anisotropic magnetoresistance in atomic contacts. 12.4. Concluding remarks and open problems -- 13. Coherent transport through molecular junctions I : basic concepts. 13.1. Identifying the transport mechanism in single-molecule junctions. 13.2. Some lessons from the resonant tunneling model. 13.3. A two-level model. 13.4. Length dependence of the conductance. 13.5. Role of conjugation in [symbol]-electron systems. 13.6. Fano resonances. 13.7. Negative differential resistance. 13.8. Final remarks. 13.9. Exercises -- 14. Coherent transport through molecular junctions II : test-bed molecules. 14.1. Coherent transport through some test-bed molecules. 14.2. Metal-molecule contact : the role of anchoring groups. 14.3. Tuning chemically the conductance : the role of side-groups. 14.4. Controlled STM-based single-molecule experiments. 14.5. Conclusions and open problems -- 15. Single-molecule transistors : Coulomb blockade and Kondo physics. 15.1. Introduction. 15.2. Charging effects in transport through nanoscale devices. 15.3. Single-molecule three-terminal devices. 15.4. Coulomb blockade theory : constant interaction model. 15.5. Towards a theory of Coulomb blockade in molecular transistors. 15.6. Intermediate coupling : cotunneling and Kondo effect. 15.7. Single-molecule transistors : experimental results. 15.8. Exercises -- 16. Vibrationally-induced inelastic current I : experiment. 16.1. Introduction. 16.2. Inelastic electron tunneling spectroscopy (IETS). 16.3. Highly conductive junctions : point-contact spectroscopy (PCS). 16.4. Crossover between PCS and IETS. 16.5. Resonant inelastic electron tunneling spectroscopy (RIETS). 16.6. Summary of vibrational signatures -- 17. Vibrationally-induced inelastic current II : theory. 17.1. Weak electron-phonon coupling regime. 17.2. Intermediate electron-phonon coupling regime. 17.3. Strong electron-phonon coupling regime. 17.4. Concluding remarks and open problems. 17.5. Exercises -- 18. The hopping regime and transport through DNA molecules. 18.1. Signatures of the hopping regime. 18.2. Hopping transport in molecular junctions : experimental examples. 18.3. DNA-based molecular junctions. 18.4. Exercises -- 19. Beyond electrical conductance : shot noise and thermal transport. 19.1. Shot noise in atomic and molecular junctions. 19.2. Heating and heat conduction. 19.3. Thermoelectricity in molecular junctions -- 20. Optical properties of current-carrying molecular junctions. 20.1. Surface-enhanced Raman spectroscopy of molecular junctions. 20.2. Transport mechanisms in irradiated molecular junctions. 20.3. Theory of photon-assisted tunneling. 20.4. Experiments on radiation-induced transport in atomic and molecular junctions. 20.5. Resonant current amplification and other transport phenomena in ac driven molecular junctions. 20.6. Fluorescence from current-carrying molecular junctions. 20.7. Molecular optoelectronic devices. 20.8. Final remarks. 20.9. Exercises -- 21. What is missing in this book?

Methods of Electronic Structure Theory

Download Methods of Electronic Structure Theory PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1475708874
Total Pages : 476 pages
Book Rating : 4.4/5 (757 download)

DOWNLOAD NOW!


Book Synopsis Methods of Electronic Structure Theory by : Henry F. Schaefer

Download or read book Methods of Electronic Structure Theory written by Henry F. Schaefer and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: These two volumes deal with the quantum theory of the electronic structure of molecules. Implicit in the term ab initio is the notion that approximate solutions of Schrödinger's equation are sought "from the beginning," i. e. , without recourse to experimental data. From a more pragmatic viewpoint, the distin guishing feature of ab initio theory is usually the fact that no approximations are involved in the evaluation of the required molecular integrals. Consistent with current activity in the field, the first of these two volumes contains chapters dealing with methods per se, while the second concerns the application of these methods to problems of chemical interest. In asense, the motivation for these volumes has been the spectacular recent success of ab initio theory in resolving important chemical questions. However, these applications have only become possible through the less visible but equally important efforts of those develop ing new theoretical and computational methods and models. Henry F Schaefer Vll Contents Contents of Volume 4 XIX Chapter 1. Gaussian Basis Sets for Molecular Calculations Thom. H. Dunning, Ir. and P. Ieffrey Hay 1. Introduction . . . . . . . . . . . . . . . . 1 1. 1. Slater Functions and the Hydrogen Moleeule 1 1. 2. Gaussian Functions and the Hydrogen Atom 3 2. Hartree-Fock Calculations on the First Row Atoms 5 2. 1. Valence States of the First Row Atoms 6 7 2. 2. Rydberg States of the First Row Atoms 9 2. 3.

Advances in the Theory of Atomic and Molecular Systems

Download Advances in the Theory of Atomic and Molecular Systems PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 9048125960
Total Pages : 448 pages
Book Rating : 4.0/5 (481 download)

DOWNLOAD NOW!


Book Synopsis Advances in the Theory of Atomic and Molecular Systems by : Piotr Piecuch

Download or read book Advances in the Theory of Atomic and Molecular Systems written by Piotr Piecuch and published by Springer Science & Business Media. This book was released on 2009-09-30 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Methods in Computational Molecular Physics

Download Methods in Computational Molecular Physics PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1461574196
Total Pages : 554 pages
Book Rating : 4.4/5 (615 download)

DOWNLOAD NOW!


Book Synopsis Methods in Computational Molecular Physics by : Stephen Wilson

Download or read book Methods in Computational Molecular Physics written by Stephen Wilson and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume records the lectures given at a NATO Advanced Study Institute on Methods in Computational Molecular Physics held in Bad Windsheim, Germany, from 22nd July until 2nd. August, 1991. This NATO Advanced Study Institute sought to bridge the quite considerable gap which exist between the presentation of molecular electronic structure theory found in contemporary monographs such as, for example, McWeeny's Methods 0/ Molecular Quantum Mechanics (Academic Press, London, 1989) or Wilson's Electron correlation in moleeules (Clarendon Press, Oxford, 1984) and the realization of the sophisticated computational algorithms required for their practical application. It sought to underline the relation between the electronic structure problem and the study of nuc1ear motion. Software for performing molecular electronic structure calculations is now being applied in an increasingly wide range of fields in both the academic and the commercial sectors. Numerous applications are reported in areas as diverse as catalysis and interstellar chernistry, drug design and environmental studies, molecular biology and solid state physics. The range of applications continues to increase as scientists recognize the importance of molecular structure studies to their research activities. Recent years have seen a growing dependence of these applications on program packages, which are often not in the public domain and which may have a somewhat lirnited range of applicability dicta ted by the particular interests and prejudices of the program author.