Gregory S Ezra

In this Festschrift dedicated to the 60th birthday of Gregory S. Ezra, selected researchers in theoretical chemistry present research highlights on major developments in the field. Originally published in the journal Theoretical Chemistry Accounts, these outstanding contributions are now available in a hardcover print format, as well as a special electronic edition. This volume provides valuable content for all researchers in theoretical chemistry and will especially benefit those research groups and libraries with limited access to the journal.

In this Festschrift dedicated to the 60th birthday of Gregory S. Ezra , selected researchers in theoretical chemistry present research highlights on major developments in the field. Originally published in the journal Theoretical Chemistry Accounts, these outstanding contributions are now available in a hardcover print format, as well as a special electronic edition. This volume provides valuable content for all researchers in theoretical chemistry, and will especially benefit those research groups and libraries with limited access to the journal.

The Fifteenth Jerusalem Symposium reflected the high standards of the former international scientific meetings, which convene once a year at the Israel Academy of Sciences and Humanities in Jerusalem to discuss a specific topic in the broad area of quantum chemistry and biochemistry. The topic at this year's Jerusalem Symposium was intramo lecular dynamics, a subject of central interest for theoreticians, che mists and biologists. During the last two decades, there has been remarkable pro gress in our understanding of time dependent phenomena. The development and application of the modern techniques of quantum mechanics and sta tistical mechanics to excited-state dynamics and to chemical and biophy sical systems constitutes a fast developing current research area. The main theme of the Symposium was built around a conceptual framework for the elucidation of photophysical and photochemical phenomena in atoms, molecules, van der Waals complexes and clusters, condensed phases, poly mers and biological supermolecules. The interdisciplinary nature of this research field was deliberated by intensive and extensive interactions between scientists from different disciplines and between theory and experiment. This volume provides a record of the invited lectures at the Symposium.

The Twenty Fourth Jerusalem Symposium reflected the high standards of these distinguished scientific meetings, which convene once a year at the Israel Academy of Sciences and Humanities in Jerusalem to discuss a specific topic in the broad area of quantum chemistry and biochemistry. The topic at this year's Jerusalem Symposium was mode selective chemistry, which constitutes a truly interdisciplinary subject of central interest in the areas of chemical physics, photochemistry and photobiology. The main theme of the Symposium was built around the exploration of the possibility and conditions for non-statistical reaction dynamics in molecules, van der Waals molecules, clusters and condensed phases. The main issues addressed photoselective and coherent excitation modes, bottlenecks for intramolecular vibrational energy redistribution, the consequences of the internal structure of many-atom systems and of rotational vibrational level structure for intramolecular dynamics, bond selective photodissociation, ultrafast chemical clocks for energy disposal, coherent control of photochemical reactions and nonstatistical unimolecular reaction dynamics. The interdisciplinary nature of this research area was deliberated by intensive and extensive interactions between theory and experiment. This volume provides a record of the invited lectures at the Symposium.

The Fourth International Congress in Quantum Chemistry under the auspices of the International Academy of Molecular Quantum Science in Menton, France was arranged at Uppsala University, Uppsala, Sweden, during the period June 14 - 19, 1982, in close collaboration with the University of Florida. The previous congresses were held in Menton 1973, New Orleans 1976, and Kyoto 1979, and the 1985 congress is tentatively planned to be held in the province of Quebec, Canada. The Congress consisted of six symposia in various areas of quantum chemistry, solid-state theory, and quantum bi ology. The meeting was attended by about 450 scientists from 45 different nations, and a total of more than 300 scientific papers were presented. Even the poster contri butions were given some plenary time. These proceedings contain the text of the plenary lec tures as well as the chairmen's introductions, whereas the contributed papers will be published in the International Journal of Quantum Chemistry, (John Wiley & Sons, New York) in the regular January - April 1983 issues.

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.