We characterize an isolated molecule by its compos~t~on, i.e. the number and types of atoms forming the molecule, its structure, i.e. the geometrical arrangement of the composite atoms with respect to each other, and its possible, i.e. quantum mechanically allowed, stationary energy states. Conceptually we separate the latter, being aware that this is an approximation, into electronic, vibrational and rotational states, including fine and hyperfine structure splittings. To be sure, there is an intimate relation between molecular structure and molecular energy states, in fact it is this relation we use, when we obtain structural information through spectroscopy, where we determine transitions between various stationary states of the molecule. The concepts above have proven extremely useful in chemistry and spectroscopy, however, the awareness of the limitations of these concepts has grown in recent years with the increasing recognition of (i) fluctional molecules, (ii) multiphoton absorption processes and (iii) influences due to the surroundings on "isolated" molecules.

Applied Atomic Collision Physics, Volume 3: Gas Lasers describes the applications of atomic collision physics in the development of many types of gas lasers. Topics covered range from negative ion formation in gas lasers to high-pressure ion kinetics and relaxation of molecules exchanging vibrational energy. Ion-ion recombination in high-pressure plasmas is also discussed, along with electron-ion recombination in gas lasers and collision processes in chemical lasers. Comprised of 14 chapters, this volume begins with a historical summary of gas laser developments and an overview of the basic operating principles of major gas laser types. The discussion then turns to the mechanism of formation of negative ions in gas lasers; ion-ion recombination in high-pressure plasmas; electron-ion recombination in gas lasers; and collision processes in chemical lasers. Subsequent chapters focus on high-energy carbon dioxide laser amplifiers; spectroscopy and excited state chemistry of excimer lasers; rare-gas halide lasers; transient optical absorption in the ultraviolet; and pre-ionized self-sustained laser discharges. The final chapter considers the stability of excimer laser discharges. This book will be of interest to physicists and chemists.

Global Physical Climatology is an introductory text devoted to the fundamental physical principles and problems of climate sensitivity and change. Addressing some of the most critical issues in climatology, this text features incisive coverage of topics that are central to understanding orbital parameter theory for past climate changes, and for anthropogenic and natural causes of near-future changes--Key Features* Covers the physics of climate change* Examines the nature of the current climate and its previous changes* Explores the sensitivity of climate and the mechanisms by which humans are likely to produce near-future climate changes* Provides instructive end-of-chapter exercises and appendices