Ranging from the basics of the atomic structure to the most advanced applications of Quantum Mechanics, the book is a complete compendium of the subject. The book is well handy of engineering and science students of B.Tech (First year Physics Course), M.Tech (Nanotechnology) and M.Sc. (Physics). The value of this interesting book lies not just in the increased scientific understanding of Physics, which one gains but in the extensive knowledge which is presented on the wide variety of technologies required to achieve application level knowledge of Quantum Mechanics. Thorough revision of various notes with considerable up-to-date material has resulted in the text as presented herein. It is hoped that this volume will stimulate the reader’s interest to pursue more specialized education in the many topics of Quantum Mechanics. Table of Contents Preface Atom and its structure Origin of the Quantum Mechanics Relational Quantum Mechanics and Optics Application of Quantum Mechanics Electromagnetic Wave Equation Single Electron Atom-Hydrogen and Scpirodinger Equation Schrodinger Wave Equation and its solutions Many Electron Atoms Definition of Atomic Charge and Quantum Mechanics The Quantum Mechanical Explanation of Chemical Bond Bibliography.