Cover -- TABLE OF CONTENTS -- PREFACE TO THE SERIES -- PREFACE TO VOLUME 23 -- PREFACE BY THE AUTHOR -- CONTENTS OF OTHER VOLUMES -- CHAPTER 1. QUANTUM CHEMISTRY OF MOLECULAR SYSTEMS RELATING TO THE CRYSTAL CHEMISTRY AND LATTICE DYNAMICS OF SILICATES -- I . Computational Methods and Wave Functions -- II . A Single Si-O Bond at the Silicon Atom -- III . Systems with Tetrahedral Oxygen Coordination of Silicon -- IV . Quantum Mechanical Computations for Some Ionic Clusters and their Relation to the Crystal Chemistry of Silicates -- References -- CHAPTER 2. INTRODUCTION TO THE DYNAMICAL THEORY OF CRYSTALS AND APPLICATION OF APPROACHES ORIGINATING FROM THE THEORY OF MOLECULAR VIBRATIONS -- I . The Elements of Dynamical Theory of Crystal Lattice -- II . A Compatibility of Molecular Force Constants with the Explicit Treatment of Coulomb Interaction in a Lattice -- III . Internal Coordinates in the Description of Dynamic Properties and Lattice Stability -- IV . Several Computational Problems -- References -- CHAPTER 3. MOLECULAR QUANTUM MECHANICS IN THE EVALUATION OF INTERACTIONS OF LESS LOCALIZED ORIGIN -- I . The Ionic Charge of Oxygen in Silicon Dioxide and the Non-Bonding Oxygen-Oxygen Interactions in Crystals -- II . Tetramethoxysilane as a Model of the Silicon-Oxygen Tetrahedron in a Network of Partially Covalent Bonds -- III . The Disilicic Acid Molecule as a Model of the Fragment of a Silica Network -- References -- CHAPTER 4. THE AB INITIO MOLECULAR FORCE CONSTANTS IN LATTICE DYNAMICS COMPUTATIONS -- I . Molecular Force Constants in Dynamical Model of a-Quartz -- II . Ab Initio Force Constants of Molecular Species in Lattice Dynamics of The Quartz-Like Aluminum Phosphate -- III . Electrostatic Contribution to the Mechanical Modes of a More Polarizable Lattice: Pyroxene- Like Monoclinic Sodium Vanadate -- References -- AUTHOR INDEX -- SUBJECT INDEX -- Last Page.