Download or read book The Unitary Group for the Evaluation of Electronic Energy Matrix Elements written by Jürgen Hinze and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last thirty years, with the development of high speed electronic computers, methods have evolved, which permit an accurate and quantitative, ab initio determina tion of the electronic wavefunctions of atoms and molecules. Thus a detailed elucida tion of the electronic energy and structure of molecules has become possible using quantum mechanics directly. Ho\~ever, it is necessary, if such calculations are to yield accurate and reliable results, to include electron correlation explicitely, which requires in general . configuration mixing procedures with an extremely large 5 number of configurations, of the order of 10 configurations. With eigenvalue problems of this size, the limits of even the largest and fastest computers are reached rapidly, and their solution has become possible only, because direct methods have been deve~ loped which permit the determination of eigenvalues and eigenvectors for such large matrices iteratively without constructing the energy matrix explicitely. These direct methods had been limited to the description of closed shell systems, i. e. systems with a single dominant closed shell reference determinant. This limitation arose, because with an open shell reference or with several reference determinants, no procedures were known, which allowed a rapid calculation of the energy matrix elements between configurations with general and widely different spin couplings, which would be necessary. Recently such methods have been developed, based on early work of Gelfand, Biedenharn and Moshinski using a unitary group representation of different spin coupled states; Paldus achieved an extremely compact description.
Download or read book The Unitary Group for the Evaluation of Electronic Energy Matrix Elements written by and published by . This book was released on 1981 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Unitary Group for the Evaluation of Electronic Energy Matrix Elements written by Jurgen Hinze and published by . This book was released on 1981-02-01 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Symmetric Group in Quantum Chemistry written by R. Pauncz and published by CRC Press. This book was released on 2018-05-04 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to provide comprehensive treatment of the use of the symmetric group in quantum chemical structures of atoms, molecules, and solids. It begins with the conventional Slater determinant approach and proceeds to the basics of the symmetric group and the construction of spin eigenfunctions. The heart of the book is in the chapter dealing with spin-free quantum chemistry showing the great interpretation value of this method. The last three chapters include the unitary group approach, the symmetric group approach, and the spin-coupled valence bond method. An extensive bibliography concludes the book.
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.
Download or read book Isaiah Shavitt written by Ron Shepard and published by Springer. This book was released on 2015-10-15 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this Festschrift dedicated to the late Isaiah Shavitt (1925-2012) , selected researchers in theoretical chemistry present research highlights on major developments in the field. Originally published in the journal Theoretical Chemistry Accounts, these outstanding contributions are now available in a hardcover print format, as well as a special electronic edition. This volume provides valuable content for all researchers in theoretical chemistry, and will especially benefit those research groups and libraries with limited access to the journal.
Download or read book Symmetry And Structural Properties Of Condensed Matter Proceedings Of The 3rd International School On Theoretical Physics written by Tadeusz Lulek and published by World Scientific. This book was released on 1995-03-29 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reviews some selected problems in solid state physics with an emphasis on adequate mathematical tools. The three main subjects are magnetic structures and neutron scattering; Berry phases and energy bands in solids (symmetry, analicity, Hofstadter butterfly, van Hove singularities); and quasicrystals, finite systems, and group action on sets (unitary group approach, Schur functions). Software presentations are included as a separate part.
Download or read book New Horizons of Quantum Chemistry written by P.-O. Löwdin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fourth International Congress in Quantum Chemistry under the auspices of the International Academy of Molecular Quantum Science in Menton, France was arranged at Uppsala University, Uppsala, Sweden, during the period June 14 - 19, 1982, in close collaboration with the University of Florida. The previous congresses were held in Menton 1973, New Orleans 1976, and Kyoto 1979, and the 1985 congress is tentatively planned to be held in the province of Quebec, Canada. The Congress consisted of six symposia in various areas of quantum chemistry, solid-state theory, and quantum bi ology. The meeting was attended by about 450 scientists from 45 different nations, and a total of more than 300 scientific papers were presented. Even the poster contri butions were given some plenary time. These proceedings contain the text of the plenary lec tures as well as the chairmen's introductions, whereas the contributed papers will be published in the International Journal of Quantum Chemistry, (John Wiley & Sons, New York) in the regular January - April 1983 issues.
Download or read book Quantum Chemistry and Dynamics of Excited States written by Leticia González and published by John Wiley & Sons. This book was released on 2020-11-10 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Symmetry adapted Basis Sets Automatic Generation For Problems In Chemistry And Physics written by John Scales Avery and published by World Scientific. This book was released on 2011-10-31 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: In theoretical physics, theoretical chemistry and engineering, one often wishes to solve partial differential equations subject to a set of boundary conditions. This gives rise to eigenvalue problems of which some solutions may be very difficult to find. For example, the problem of finding eigenfunctions and eigenvalues for the Hamiltonian of a many-particle system is usually so difficult that it requires approximate methods, the most common of which is expansion of the eigenfunctions in terms of basis functions that obey the boundary conditions of the problem. The computational effort needed in such problems can be much reduced by making use of symmetry-adapted basis functions. The conventional method for generating symmetry-adapted basis sets is through the application of group theory, but this can be difficult. This book describes an easier method for generating symmetry-adapted basis sets automatically with computer techniques. The method has a wide range of applicability, and can be used to solve difficult eigenvalue problems in a number of fields. The book is of special interest to quantum theorists, computer scientists, computational chemists and applied mathematicians.
Download or read book Aspects of Many Body Effects in Molecules and Extended Systems written by Debashis Mukherjee and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume features invited lectures presented in the workshop-cum-symposium on aspects of many-body effects in molecules and extended systems, Calcutta, February 1 - 10, 1988. The organizers invited leading experts to present recent developments of many-body methods as applied to molecules and condensed systems. The panorama portrayed is quite broad, but by no means exhaustive. The emphasis is undoubtedly on a "molecular point of view".
Download or read book Advances in Chemical Physics Volume 110 written by Ilya Prigogine and published by John Wiley & Sons. This book was released on 2009-09-09 with total page 571 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline. Volume 110 continues to report recent advances with important, up-to-date chapters contributed by internationally recognized researchers.
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.
Download or read book Relativistic and Electron Correlation Effects in Molecules and Solids written by G.L. Malli and published by Springer Science & Business Media. This book was released on 2013-11-21 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NATO Advanced Study Institute (ASI) on "R@lativistic and Electron Correlation Effects in Molecules and Solids", co-sponsored by Simon Fraser University (SFU) and the Natural Sciences and Engineering Research Council of Canada (NSERC) was held Aug 10- 21, 1992 at the University of British Columbia (UBC), Vancouver, Canada. A total of 90 lecturers and students with backgrounds in Chemistry, Physics, Mathematics and various interdisciplinary subjects attended the ASI. In my proposal submitted to NATO for financial support for this ASI, I pointed out that a NATO ASI on the effects of relativity in many-electron systems was held ten years ago, [See G.L. Malli, (ed) Relativistic Effects in Atoms, Molecules and Solids, Plenum Press, Vol B87, New York, 1983]. Moreover, at a NATO Advanced Research Workshop (ARW) on advanced methods for molecular electronic structure "an assessment of state-of the-art of Electron Correlation ... " was carried out [see C.E. Dykstra, (ed), Advanced Theories and Computational Approaches to the Electronic Structure of Molecules, D. Reidel Publishin~ Company, Vol C133, Dordrecht, The Netherlands 1984]. However, during the last five years, it has become clear that the relativistic and electron correlation effects must be included in the theoretical treatment of many-electron molecules and solids of heavy elements (with Z > 70). Molecules and clusters containing heavy elements are of crucial importance in a number of areas of Chemistry and Physics such as nuclear fuels, catalysis, surface science, etc.
Download or read book GRMS or Graphical Representation of Model Spaces written by Wlodzislaw Duch and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of these notes is to give some simple tools and pictures to physicists and ' chemists working on the many-body problem. Abstract thinking and seeing have much in common - we say "I see" meaning "I understand" , for example. Most of us prefer to have a picture of an abstract object. The remarkable popularity of the Feynman diagrams, and other diagrammatic approaches to many-body problem derived thereof, may be partially due to this preference. Yet, paradoxically, the concept of a linear space, as fundamental to quantum physics as it is, has never been cast in a graphical form. We know that is a high-order contribution to a two-particle scattering process (this one invented by Cvitanovic(1984)) corresponding to a complicated matrix element. The lines in such diagrams are labeled by indices of single-particle states. When things get complicated at this level it should be good to take a global view from the perspective of the whole many-particle space. But how to visualize the space of all many-particle states ? Methods of such visualization or graphical representation of the ,spaces of interest to physicists and chemists are the main topic of this work.
Download or read book Ab Initio Methods in Quantum Chemistry Volume 69 Part 2 written by K. P. Lawley and published by John Wiley & Sons. This book was released on 2009-09-08 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.
Download or read book Potential Energy Functions in Conformational Analysis written by Kjeld Rasmussen 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: I get by with a little help from my friends The Beatles: Sgt. Pepper This book should have been in Danish. Any decent person must be able to express himself in his mother's tongue, also when expounding scientific ideas and results. Had I stuck to this ideal, the book would have been read by very few people, and, indeed, appreciated by even fewer. Having it publ ished in English gives me a chance to fulfill one ambition: to be read and judged by the international scientific community. Another reason is that the majority of my professional friends are regrettably unread in Danish, just as I am in Hebrew, Finnish and even Italian. I want to deprive them of the most obvious excuse for not reading my opus. Like a man I admired, I will first of all thank my wife. In his autobiography, Meir Weisgal, then President of the Weizmann Insti tute of SCience, wrote about his wife: "In addition to her natural endowments - which are considerable - she was a more than competent part-tim~ secretary." He wrote on, and so shall I. The book has been edited by my wife. So if the reader finds the layout pleasant as, in actual fact, I myself do, Birgit is to be praised. If there are blemishes, I am to be blamed for not having caught them.
