Author: Odilon Chalvet
Publisher: Springer Science & Business Media
ISBN: 9401014566
Category : Science
Languages : en
Pages : 470
Book Description
The second volume of the proceedings of the international seminar devoted to locali· zation and delocalization in quantum chemistry is divided into four parts. The first one is mainly concerned with the localizability of electrons in ionized and exited states. The second part shows how is it possible to take advantage of the localizability of electrons to compute molecular wave-functions. The third part of the book is an homogeneous analysis of the electronic collective excitation and of the motion of excitons in organic solids. The last section is devoted to the study of the role of electron localizability in the chemical reactivity of molecules. Concluding remarks are concerned with a careful analysis of the localizability concept itself in relation with a possible interpretation of the wave-mechanics. PART I ELECTRON LOCALIZATION IN IONIZED AND EXCITED STATES APPLICATIONS OF PAIR DENSITY ANALYSIS R. CONSTANCIEL and L. ESNAULT Centre de Mecanique Ondulatoire Appliquee, Paris, France Abstract. The method of pair density analysis is applied to various kinds of calculations. We examine the influence of the quality of the wavefunction and of the nuclear configuration; the problem of hybridization is discussed, as weIl as the relations between separability and excitation.
Atoms and Molecules in the Ground State
Author: Odilon Chalvet
Publisher: Springer Science & Business Media
ISBN: 9401017786
Category : Science
Languages : en
Pages : 345
Book Description
Publisher: Springer Science & Business Media
ISBN: 9401017786
Category : Science
Languages : en
Pages : 345
Book Description
Localization and Delocalization in Quantum Chemistry
Author: Odilon Chalvet
Publisher: Springer Science & Business Media
ISBN: 9401014566
Category : Science
Languages : en
Pages : 470
Book Description
The second volume of the proceedings of the international seminar devoted to locali· zation and delocalization in quantum chemistry is divided into four parts. The first one is mainly concerned with the localizability of electrons in ionized and exited states. The second part shows how is it possible to take advantage of the localizability of electrons to compute molecular wave-functions. The third part of the book is an homogeneous analysis of the electronic collective excitation and of the motion of excitons in organic solids. The last section is devoted to the study of the role of electron localizability in the chemical reactivity of molecules. Concluding remarks are concerned with a careful analysis of the localizability concept itself in relation with a possible interpretation of the wave-mechanics. PART I ELECTRON LOCALIZATION IN IONIZED AND EXCITED STATES APPLICATIONS OF PAIR DENSITY ANALYSIS R. CONSTANCIEL and L. ESNAULT Centre de Mecanique Ondulatoire Appliquee, Paris, France Abstract. The method of pair density analysis is applied to various kinds of calculations. We examine the influence of the quality of the wavefunction and of the nuclear configuration; the problem of hybridization is discussed, as weIl as the relations between separability and excitation.
Publisher: Springer Science & Business Media
ISBN: 9401014566
Category : Science
Languages : en
Pages : 470
Book Description
The second volume of the proceedings of the international seminar devoted to locali· zation and delocalization in quantum chemistry is divided into four parts. The first one is mainly concerned with the localizability of electrons in ionized and exited states. The second part shows how is it possible to take advantage of the localizability of electrons to compute molecular wave-functions. The third part of the book is an homogeneous analysis of the electronic collective excitation and of the motion of excitons in organic solids. The last section is devoted to the study of the role of electron localizability in the chemical reactivity of molecules. Concluding remarks are concerned with a careful analysis of the localizability concept itself in relation with a possible interpretation of the wave-mechanics. PART I ELECTRON LOCALIZATION IN IONIZED AND EXCITED STATES APPLICATIONS OF PAIR DENSITY ANALYSIS R. CONSTANCIEL and L. ESNAULT Centre de Mecanique Ondulatoire Appliquee, Paris, France Abstract. The method of pair density analysis is applied to various kinds of calculations. We examine the influence of the quality of the wavefunction and of the nuclear configuration; the problem of hybridization is discussed, as weIl as the relations between separability and excitation.
Localization and Delocalization in Quantum Chemistry
Localization and Delocalization in Quantum Chemistry
Author: Odilon Chalvet
Publisher: Springer
ISBN:
Category : Science
Languages : en
Pages : 506
Book Description
The second volume of the proceedings of the international seminar devoted to locali· zation and delocalization in quantum chemistry is divided into four parts. The first one is mainly concerned with the localizability of electrons in ionized and exited states. The second part shows how is it possible to take advantage of the localizability of electrons to compute molecular wave-functions. The third part of the book is an homogeneous analysis of the electronic collective excitation and of the motion of excitons in organic solids. The last section is devoted to the study of the role of electron localizability in the chemical reactivity of molecules. Concluding remarks are concerned with a careful analysis of the localizability concept itself in relation with a possible interpretation of the wave-mechanics. PART I ELECTRON LOCALIZATION IN IONIZED AND EXCITED STATES APPLICATIONS OF PAIR DENSITY ANALYSIS R. CONSTANCIEL and L. ESNAULT Centre de Mecanique Ondulatoire Appliquee, Paris, France Abstract. The method of pair density analysis is applied to various kinds of calculations. We examine the influence of the quality of the wavefunction and of the nuclear configuration; the problem of hybridization is discussed, as weIl as the relations between separability and excitation.
Publisher: Springer
ISBN:
Category : Science
Languages : en
Pages : 506
Book Description
The second volume of the proceedings of the international seminar devoted to locali· zation and delocalization in quantum chemistry is divided into four parts. The first one is mainly concerned with the localizability of electrons in ionized and exited states. The second part shows how is it possible to take advantage of the localizability of electrons to compute molecular wave-functions. The third part of the book is an homogeneous analysis of the electronic collective excitation and of the motion of excitons in organic solids. The last section is devoted to the study of the role of electron localizability in the chemical reactivity of molecules. Concluding remarks are concerned with a careful analysis of the localizability concept itself in relation with a possible interpretation of the wave-mechanics. PART I ELECTRON LOCALIZATION IN IONIZED AND EXCITED STATES APPLICATIONS OF PAIR DENSITY ANALYSIS R. CONSTANCIEL and L. ESNAULT Centre de Mecanique Ondulatoire Appliquee, Paris, France Abstract. The method of pair density analysis is applied to various kinds of calculations. We examine the influence of the quality of the wavefunction and of the nuclear configuration; the problem of hybridization is discussed, as weIl as the relations between separability and excitation.
Advances in Quantum Chemistry
Author:
Publisher: Academic Press
ISBN: 0080582613
Category : Science
Languages : en
Pages : 417
Book Description
Advances in Quantum Chemistry publishes articles and invited reviews by leading international researchers in quantum chemistry. Quantum chemistry deals particularly with the electronic structure of atoms, molecules, and crystalline matter and describes it in terms of electron wave patterns. It uses physical and chemical insight, sophisticated mathematics and high-speed computers to solve the wave equations and achieve its results. Advances highlights these important, interdisciplinary developments.
Publisher: Academic Press
ISBN: 0080582613
Category : Science
Languages : en
Pages : 417
Book Description
Advances in Quantum Chemistry publishes articles and invited reviews by leading international researchers in quantum chemistry. Quantum chemistry deals particularly with the electronic structure of atoms, molecules, and crystalline matter and describes it in terms of electron wave patterns. It uses physical and chemical insight, sophisticated mathematics and high-speed computers to solve the wave equations and achieve its results. Advances highlights these important, interdisciplinary developments.
Theoretical Models of Chemical Bonding
Author: Zvonimir B. Maksic
Publisher: Springer Science & Business Media
ISBN: 364258179X
Category : Science
Languages : en
Pages : 643
Book Description
The renowned theoretical physicist Victor F. Weisskopf rightly pointed out that a real understanding of natural phenomena implies a clear distinction between the essential and the peripheral. Only when we reach such an understanding - that is to say when we are able to separate the relevant from the irrelevant, will the phenomena no longer appear complex, but intelectually transparent. This statement, which is generally valid, reflects the very essence ofmodelling in the quantum theory of matter, on the molecular level in particular. Indeed, without theoretical models one would be swamped by too many details embodied in intricate accurate molecular wavefunctions. Further, physically justified simplificqtions enable studies of the otherwise intractable systems and/or phenomena. Finally, a lack of appropriate models would leave myriads of raw experimental data totally unrelated and incomprehensible. The present series ofbooks dwells on the most important models of chemical bonding and on the variety of its manifestations. In this volume the electronic structure and properties of molecules are considered in depth. Particular attention is focused on the nature of intramolecular interactions which in turn are revealed by various types ofmolecular spectroscopy. Emphasis is put on the conceptual and interpretive aspects of the theory in line with the general philosophy adopted in the series.
Publisher: Springer Science & Business Media
ISBN: 364258179X
Category : Science
Languages : en
Pages : 643
Book Description
The renowned theoretical physicist Victor F. Weisskopf rightly pointed out that a real understanding of natural phenomena implies a clear distinction between the essential and the peripheral. Only when we reach such an understanding - that is to say when we are able to separate the relevant from the irrelevant, will the phenomena no longer appear complex, but intelectually transparent. This statement, which is generally valid, reflects the very essence ofmodelling in the quantum theory of matter, on the molecular level in particular. Indeed, without theoretical models one would be swamped by too many details embodied in intricate accurate molecular wavefunctions. Further, physically justified simplificqtions enable studies of the otherwise intractable systems and/or phenomena. Finally, a lack of appropriate models would leave myriads of raw experimental data totally unrelated and incomprehensible. The present series ofbooks dwells on the most important models of chemical bonding and on the variety of its manifestations. In this volume the electronic structure and properties of molecules are considered in depth. Particular attention is focused on the nature of intramolecular interactions which in turn are revealed by various types ofmolecular spectroscopy. Emphasis is put on the conceptual and interpretive aspects of the theory in line with the general philosophy adopted in the series.
The Concept of the Chemical Bond
Author: Zvonimir B. Maksic
Publisher: Springer
ISBN: 9783540515531
Category : Science
Languages : en
Pages : 544
Book Description
The state-of-the-art in contemporary theoretical chemistry is presented in this 4-volume set with numerous contributions from the most highly regarded experts in their field. It provides a concise introduction and critical evaluation of theoretical approaches in relation to experimental evidence.
Publisher: Springer
ISBN: 9783540515531
Category : Science
Languages : en
Pages : 544
Book Description
The state-of-the-art in contemporary theoretical chemistry is presented in this 4-volume set with numerous contributions from the most highly regarded experts in their field. It provides a concise introduction and critical evaluation of theoretical approaches in relation to experimental evidence.
The Chemical Bond
Author: Gernot Frenking
Publisher: John Wiley & Sons
ISBN: 3527333142
Category : Science
Languages : en
Pages : 450
Book Description
This is the perfect complement to "Chemical Bonding - Across the Periodic Table" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemical models and faster computers.
Publisher: John Wiley & Sons
ISBN: 3527333142
Category : Science
Languages : en
Pages : 450
Book Description
This is the perfect complement to "Chemical Bonding - Across the Periodic Table" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemical models and faster computers.
Theoretical Models of Chemical Bonding
Author: Zvonimir B. Maksić
Publisher: Springer Science & Business Media
ISBN: 9783540522522
Category : Science
Languages : en
Pages : 668
Book Description
The state-of-the-art in contemporary theoretical chemistry is presented in this 4-volume set with numerous contributions from the most highly regarded experts in their field. It provides a concise introduction and critical evaluation of theoretical approaches in relation to experimental evidence.
Publisher: Springer Science & Business Media
ISBN: 9783540522522
Category : Science
Languages : en
Pages : 668
Book Description
The state-of-the-art in contemporary theoretical chemistry is presented in this 4-volume set with numerous contributions from the most highly regarded experts in their field. It provides a concise introduction and critical evaluation of theoretical approaches in relation to experimental evidence.
Semiempirical Methods of Electronic Structure Calculation
Author: Gerald Segal
Publisher: Springer Science & Business Media
ISBN: 1468425560
Category : Science
Languages : en
Pages : 285
Book Description
If one reflects upon the range of chemical problems accessible to the current quantum theoretical methods for calculations on the electronic structure of molecules, one is immediately struck by the rather narrow limits imposed by economic and numerical feasibility. Most of the systems with which experimental photochemists actually work are beyond the grasp of ab initio methods due to the presence of a few reasonably large aromatic ring systems. Potential energy surfaces for all but the smallest molecules are extremely expensive to produce, even over a restricted group of the possible degrees of freedom, and molecules containing the higher elements of the periodic table remain virtually untouched due to the large numbers of electrons involved. Almost the entire class of molecules of real biological interest is simply out of the question. In general, the theoretician is reduced to model systems of variable appositeness in most of these fields. The fundamental problem, from a basic computational point of view, is that large molecules require large numbers of basis functions, whether Slater type orbitals or Gaussian functions suitably contracted, to provide even a modestly accurate description of the molecular electronic environment. This leads to the necessity of dealing with very large matrices and numbers of integrals within the Hartree-Fock approximation and quickly becomes both numerically difficult and uneconomic.
Publisher: Springer Science & Business Media
ISBN: 1468425560
Category : Science
Languages : en
Pages : 285
Book Description
If one reflects upon the range of chemical problems accessible to the current quantum theoretical methods for calculations on the electronic structure of molecules, one is immediately struck by the rather narrow limits imposed by economic and numerical feasibility. Most of the systems with which experimental photochemists actually work are beyond the grasp of ab initio methods due to the presence of a few reasonably large aromatic ring systems. Potential energy surfaces for all but the smallest molecules are extremely expensive to produce, even over a restricted group of the possible degrees of freedom, and molecules containing the higher elements of the periodic table remain virtually untouched due to the large numbers of electrons involved. Almost the entire class of molecules of real biological interest is simply out of the question. In general, the theoretician is reduced to model systems of variable appositeness in most of these fields. The fundamental problem, from a basic computational point of view, is that large molecules require large numbers of basis functions, whether Slater type orbitals or Gaussian functions suitably contracted, to provide even a modestly accurate description of the molecular electronic environment. This leads to the necessity of dealing with very large matrices and numbers of integrals within the Hartree-Fock approximation and quickly becomes both numerically difficult and uneconomic.