This unified treatment introduces upper-level undergraduates and graduate students to the concepts and methods of modern molecular spectroscopy and their applications to quantum electronics, lasers, and related optical phenomena. Starting with a review of the prerequisite quantum mechanical background, the text examines atomic spectra and diatomic molecules, including the rotation and vibration of diatomic molecules and their electronic spectra. A discussion of rudimentary group theory advances to considerations of the rotational spectra of polyatomic molecules and their vibrational and electronic spectra; molecular beams, masers, and lasers; and a variety of forms of spectroscopy, including optical resonance spectroscopy, coherent transient spectroscopy, multiple-photon spectroscopy, and spectroscopy beyond molecular constants. The text concludes with a series of useful appendixes.

"It is the object of this graduate-level textbook to provide a back-ground of basic spectroscopic principles adequate for understanding much of both traditional and contemporary spectroscopy."--Journal of the American Chemical Society

The fundamental understanding of the production of biological effects by ionizing radiation may well be one of the most important scientific objectives of mankind; such understanding could lead to the effective and safe utilization of the nuclear energy option. In addition, this knowledge will be of immense value in such diverse fields as radiation therapy and diagnosis and in the space program. To achieve the above stated objective, the U. S. Department of Energy (DOE) and its predecessors embarked upon a fundamental interdisciplinary research program some 35 years ago. A critical component of this program is the Radiological and Chemical Physics Program (RCPP). When the RCPP was established, there was very little basic knowledge in the fields of physics, chemistry, and biology that could be directly applied to understanding the effects of radiation on biological systems. Progress of the RCPP program in its first 15 years was documented in the proceedings of a conference held at Airlie, Virginia, in 1972. At this conference, it was clear that considerable progr:ess had been made in research on the physical and chemical processes in well-characterized systems that could be used to understand biological effects. During this period of time, most physical knowledge was obtained for the gas phase because the technology and instru mentation had not progressed to the point that measurements could be made in liquids more characteristic of biological materials.

This book describes selected problems in contemporary spectroscopy in the context of quantum mechanics and statistical physics. It focuses on elementary radiative processes involving atomic particles (atoms, molecules, ions), which include radiative transitions between discrete atomic states, the photoionization of atoms, photorecombination of electrons and ions, bremsstrahlung, photodissociation of molecules, and photoattachment of electrons to atoms. In addition to these processes, the transport of resonant radiation in atomic gases and propagation of infrared radiation in molecular gases are also considered. The book subsequently addresses applied problems such as optical pumping, cooling of gases via laser resonance radiation, light-induced drift of gas atoms, photoresonant plasma, reflection of radio waves from the ionosphere, and detection of submillimeter radiation using Rydberg atoms. Lastly, topical examples in atmospheric and climate change science are presented, such as lightning channel glowing, emission of the solar photosphere, and the greenhouse phenomenon in the atmospheres of the Earth and Venus. Along with researchers, both graduate and undergraduate students in atomic, molecular and atmospheric physics will find this book a useful and timely guide.

Atoms and Molecules describes the basic properties of atoms and molecules in terms of group theoretical methods in atomic and molecular physics. The book reviews mathematical concepts related to angular momentum properties, finite and continuous rotation groups, tensor operators, the Wigner-Eckart theorem, vector fields, and vector spherical harmonics. The text also explains quantum mechanics, including symmetry considerations, second quantization, density matrices, time-dependent, and time-independent approximation methods. The book explains atomic structure, particularly the Dirac equation in which its nonrelativistic approximation provides the basis for the derivation of the Hamiltonians for all important interactions, such as spin-orbit, external fields, hyperfine. Along with multielectron atoms, the text discusses multiplet theory, the Hartree-Fock formulation, as well as the electromagnetic radiation fields, their interactions with atoms in first and higher orders. The book explores molecules and complexes, including the Born-Oppenheimer approximation, molecular orbitals, the self-consistent field method, electronic states, vibrational and rotational states, molecular spectra, and the ligand field theory. The book can prove useful for graduate or advanced students and academicians in the field of general and applied physics.

There can hardly be any doubt that radiation will continue to be an im portant factor in our lives. Present and future advances in atomic tech nology urgently require further work on research and development in the field of radiation biology if the maximum benefit is to be obtained at minimal risk from the various kinds of radiation that form a major by product of nuclear processes. Consequently, it is also necessary to prepare students and younger scientists for doing such work. The present book originates from teaching experience gained in lectures, seminars, and discussion groups started by the undersigned in 1957 and more recently held together with Drs. Dertinger and Jung. The friendly comments given to the German edition made us feel that it might be worth while to put the results of our efforts at the disposal of those to whom English is more familiar. In agreement with the view, based on well-known facts, that most if not aIl of the more striking practical achievements have resulted from patient and careful investigations into some basic problem, the book aims at introducing the reader to the methods of thought and experiment used in molecular radiation biology as weIl as to the results obtained thereby.