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Approximation of the Electron Density of Aluminium Clusters in Tensor-product Format

Approximation of the Electron Density of Aluminium Clusters in Tensor-product Format PDF Author: Thomas Blesgen
Publisher:
ISBN:
Category :
Languages : en
Pages :

Book Description
The tensor-structured methods developed recently for the accurate calculation of the Hartree and the non-local exchange operators have been applied successfully to the ab initio numerical solution of the Hartree-Fock equation for some molecules. In the present work, we show that the rank-structured representation can be gainfully applied to the accurate approximation of the electron density of large Aluminium clusters. We consider the Tucker-type decomposition of the electron density of certain Aluminium clusters originating from finite element calculations in the framework of the orbital-free density functional theory. Numerical investigations of the Tucker approximation of the corresponding electron density reveal the exponential decay of the approximation error with respect to the Tucker rank. The resulting lowrank tensor representation reduces dramatically the storage needs and the computational complexity of the consequent tensor operations on the electron density. As main result, the rank of the Tucker approximation for the accurate representation of the electron density is very small and only very weakly dependent on the system size, which shows good promise for resolving the electronic structure of materials using tensor-structured techniques.

Approximation of the Electron Density of Aluminium Clusters in Tensor-product Format

Approximation of the Electron Density of Aluminium Clusters in Tensor-product Format PDF Author: Thomas Blesgen
Publisher:
ISBN:
Category :
Languages : en
Pages :

Book Description
The tensor-structured methods developed recently for the accurate calculation of the Hartree and the non-local exchange operators have been applied successfully to the ab initio numerical solution of the Hartree-Fock equation for some molecules. In the present work, we show that the rank-structured representation can be gainfully applied to the accurate approximation of the electron density of large Aluminium clusters. We consider the Tucker-type decomposition of the electron density of certain Aluminium clusters originating from finite element calculations in the framework of the orbital-free density functional theory. Numerical investigations of the Tucker approximation of the corresponding electron density reveal the exponential decay of the approximation error with respect to the Tucker rank. The resulting lowrank tensor representation reduces dramatically the storage needs and the computational complexity of the consequent tensor operations on the electron density. As main result, the rank of the Tucker approximation for the accurate representation of the electron density is very small and only very weakly dependent on the system size, which shows good promise for resolving the electronic structure of materials using tensor-structured techniques.

Tensor Numerical Methods in Scientific Computing

Tensor Numerical Methods in Scientific Computing PDF Author: Boris N. Khoromskij
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 311036591X
Category : Mathematics
Languages : en
Pages : 382

Book Description
The most difficult computational problems nowadays are those of higher dimensions. This research monograph offers an introduction to tensor numerical methods designed for the solution of the multidimensional problems in scientific computing. These methods are based on the rank-structured approximation of multivariate functions and operators by using the appropriate tensor formats. The old and new rank-structured tensor formats are investigated. We discuss in detail the novel quantized tensor approximation method (QTT) which provides function-operator calculus in higher dimensions in logarithmic complexity rendering super-fast convolution, FFT and wavelet transforms. This book suggests the constructive recipes and computational schemes for a number of real life problems described by the multidimensional partial differential equations. We present the theory and algorithms for the sinc-based separable approximation of the analytic radial basis functions including Green’s and Helmholtz kernels. The efficient tensor-based techniques for computational problems in electronic structure calculations and for the grid-based evaluation of long-range interaction potentials in multi-particle systems are considered. We also discuss the QTT numerical approach in many-particle dynamics, tensor techniques for stochastic/parametric PDEs as well as for the solution and homogenization of the elliptic equations with highly-oscillating coefficients. Contents Theory on separable approximation of multivariate functions Multilinear algebra and nonlinear tensor approximation Superfast computations via quantized tensor approximation Tensor approach to multidimensional integrodifferential equations

Tensor Numerical Methods in Quantum Chemistry

Tensor Numerical Methods in Quantum Chemistry PDF Author: Venera Khoromskaia
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110365839
Category : Mathematics
Languages : en
Pages : 298

Book Description
The conventional numerical methods when applied to multidimensional problems suffer from the so-called "curse of dimensionality", that cannot be eliminated by using parallel architectures and high performance computing. The novel tensor numerical methods are based on a "smart" rank-structured tensor representation of the multivariate functions and operators discretized on Cartesian grids thus reducing solution of the multidimensional integral-differential equations to 1D calculations. We explain basic tensor formats and algorithms and show how the orthogonal Tucker tensor decomposition originating from chemometrics made a revolution in numerical analysis, relying on rigorous results from approximation theory. Benefits of tensor approach are demonstrated in ab-initio electronic structure calculations. Computation of the 3D convolution integrals for functions with multiple singularities is replaced by a sequence of 1D operations, thus enabling accurate MATLAB calculations on a laptop using 3D uniform tensor grids of the size up to 1015. Fast tensor-based Hartree-Fock solver, incorporating the grid-based low-rank factorization of the two-electron integrals, serves as a prerequisite for economical calculation of the excitation energies of molecules. Tensor approach suggests efficient grid-based numerical treatment of the long-range electrostatic potentials on large 3D finite lattices with defects.The novel range-separated tensor format applies to interaction potentials of multi-particle systems of general type opening the new prospects for tensor methods in scientific computing. This research monograph presenting the modern tensor techniques applied to problems in quantum chemistry may be interesting for a wide audience of students and scientists working in computational chemistry, material science and scientific computing.

Tensor Numerical Methods in Quantum Chemistry

Tensor Numerical Methods in Quantum Chemistry PDF Author: Venera Khoromskaia
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110391376
Category : Mathematics
Languages : en
Pages : 343

Book Description
The conventional numerical methods when applied to multidimensional problems suffer from the so-called "curse of dimensionality", that cannot be eliminated by using parallel architectures and high performance computing. The novel tensor numerical methods are based on a "smart" rank-structured tensor representation of the multivariate functions and operators discretized on Cartesian grids thus reducing solution of the multidimensional integral-differential equations to 1D calculations. We explain basic tensor formats and algorithms and show how the orthogonal Tucker tensor decomposition originating from chemometrics made a revolution in numerical analysis, relying on rigorous results from approximation theory. Benefits of tensor approach are demonstrated in ab-initio electronic structure calculations. Computation of the 3D convolution integrals for functions with multiple singularities is replaced by a sequence of 1D operations, thus enabling accurate MATLAB calculations on a laptop using 3D uniform tensor grids of the size up to 1015. Fast tensor-based Hartree-Fock solver, incorporating the grid-based low-rank factorization of the two-electron integrals, serves as a prerequisite for economical calculation of the excitation energies of molecules. Tensor approach suggests efficient grid-based numerical treatment of the long-range electrostatic potentials on large 3D finite lattices with defects.The novel range-separated tensor format applies to interaction potentials of multi-particle systems of general type opening the new prospects for tensor methods in scientific computing. This research monograph presenting the modern tensor techniques applied to problems in quantum chemistry may be interesting for a wide audience of students and scientists working in computational chemistry, material science and scientific computing.

Quantities, Units and Symbols in Physical Chemistry

Quantities, Units and Symbols in Physical Chemistry PDF Author: International Union of Pure and Applied Chemistry. Physical and Biophysical Chemistry Division
Publisher: Royal Society of Chemistry
ISBN: 0854044337
Category : Reference
Languages : en
Pages : 240

Book Description
Prepared by the IUPAC Physical Chemistry Division this definitive manual, now in its third edition, is designed to improve the exchange of scientific information among the readers in different disciplines and across different nations. This book has been systematically brought up to date and new sections added to reflect the increasing volume of scientific literature and terminology and expressions being used. The Third Edition reflects the experience of the contributors with the previous editions and the comments and feedback have been integrated into this essential resource. This edition has been compiled in machine-readable form and will be available online.

Modern Electronic Structure Theory

Modern Electronic Structure Theory PDF Author: D. R. Yarkony
Publisher: World Scientific
ISBN: 9812832114
Category : Science
Languages : en
Pages : 785

Book Description
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.

The Chemical Bond in Inorganic Chemistry

The Chemical Bond in Inorganic Chemistry PDF Author: Ian David Brown
Publisher:
ISBN: 0198508700
Category : Science
Languages : en
Pages : 289

Book Description
This book describes the bond valence model, a description of acid-base bonding which is becoming increasingly popular particularly in fields such as materials science and mineralogy where solid state inorganic chemistry is important. Recent improvements in crystal structure determination have allowed the model to become more quantitative. Unlike other models of inorganic chemical bonding, the bond valence model is simple, intuitive, and predictive, and can be used for analysing crystal structures and the conceptual modelling of local as well as extended structures. This is the first book to explore in depth the theoretical basis of the model and to show how it can be applied to synthetic and solution chemistry. It emphasizes the separate roles of the constraints of chemistry and of three-dimensional space by analysing the chemistry of solids. Many applications of the model in physics, materials science, chemistry, mineralogy, soil science, surface science, and molecular biology are reviewed. The final chapter describes how the bond valence model relates to and represents a simplification of other models of inorganic chemical bonding.

The Physics of Quantum Mechanics

The Physics of Quantum Mechanics PDF Author: James Binney
Publisher: Oxford University Press, USA
ISBN: 0199688575
Category : Science
Languages : en
Pages : 408

Book Description
This title gives students a good understanding of how quantum mechanics describes the material world. The text stresses the continuity between the quantum world and the classical world, which is merely an approximation to the quantum world.

Optical Properties of Solids

Optical Properties of Solids PDF Author: Frederick Wooten
Publisher: Academic Press
ISBN: 1483220761
Category : Science
Languages : en
Pages : 273

Book Description
Optical Properties of Solids covers the important concepts of intrinsic optical properties and photoelectric emission. The book starts by providing an introduction to the fundamental optical spectra of solids. The text then discusses Maxwell's equations and the dielectric function; absorption and dispersion; and the theory of free-electron metals. The quantum mechanical theory of direct and indirect transitions between bands; the applications of dispersion relations; and the derivation of an expression for the dielectric function in the self-consistent field approximation are also encompassed. The book further tackles current-current correlations; the fluctuation-dissipation theorem; and the effect of surface plasmons on optical properties and photoemission. People involved in the study of the optical properties of solids will find the book invaluable.

Molecular Electronic-Structure Theory

Molecular Electronic-Structure Theory PDF Author: Trygve Helgaker
Publisher: John Wiley & Sons
ISBN: 1119019559
Category : Science
Languages : en
Pages : 949

Book Description
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.