Ohm, Yngve

We are honored to assemble this volume, as Yngve Ohm s influence and example have informed, inspired, and guided each of us. His integrity, dedication, and insight have benefited a broad community of scientists. We look forward to many more years of association with Yngve and to the fimits of his work. 

Yngve Ohm s research profile added an essential element in early 1964. A paper of lasting influence in theoretical chemistry and physics was published by John Hubbard in the November 26, 1963 issue of the Proceedings of the Royal... 

It is a pleasure for us who are friends, colleagues, and collaborators, to offer this contribution to a volume published in honor of Yngve Ohm s bS " birthday. For most of his career, Yngve has been interested in response properties of various systems to various probes, and we offer this contribution in that spirit. The Generalized Oscillator Strength, the subject of this paper, is the materials property that describes the response of a medium to swift particle, and thus, perhaps, an appropriate subject for this volume. Mostly, we are happy to take this opportunity to thank Yngve for his help, inspiration, and friendship over the years. 

Dedicated to Professor Yngve Ohm on the occasion of his 65th birthday... 

In this volume dedicated to Yngve Ohm we feel it is particularly appropriate to extend his ideas and merge them with the powerful practical and conceptual tools of Density Functional Theory (6). We extend the formalism used in the TDVP to mixed states and consider the states to be labeled by the densities of electronic space and spin coordinates. (In the treatment presented here we do not explicitly consider the nuclei but consider them to be fixed. Elsewhere we shall show that it is indeed straightforward to extend our treatment in the same way as Ohm et al. and obtain equations that avoid the Bom-Oppenheimer Approximation.) In this article we obtain a formulation of exact equations for the evolution of electronic space-spin densities, which are equivalent to the Heisenberg equation of motion for the electtons in the system. Using the observation that densities can be expressed as quadratic expansions of functions, we also obtain exact equations for Aese one-particle functions. 

It is difficult not to be sentimental when I(MKM) recall my graduate studentship under Yngve Ohm. I feel privileged to have had him as my supervisor and it is with utmost pleasure that I take this opportunity to record my deep gratitude to him for his fine example combining high scientific achievement with superlative human qualities. 

This volume of Advances in Quantum Chemistry honors the many accomplishments of Dr. N. Yngve Ohm on the occasion of his 65th birthday. The authors invited to contribute to this volume include past and present students, postdoctoral associates, and collaborators of Dr. Ohm. 

Acknowledgments The discussion of the theoretical basis of semi-empirical methods would not have been possible without the help and advice of several friends and colleagues, including Drs. Yngve Ohm, James Stewart, Michael Zemer, Henry Rzepa, and Marshall Cory, Jr. I am also indebted to the authors of many previous reviews of semi-empirical methods and to Anne-Marie Sapse for her patience. 

Prasanta K. Mukherjee (141), Institute de Eisica, Universidade de Sab Paulo, CP 66318, 05315-970, Sab Paulo, SP, Brazil Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India Lene B. Oddershede (xvii). The Niels Bohr Institute, Blegdamsvej 17, Copenhagen 0, Denmark J. Oddershede (253), Syddansk Universitet, Campusvej 55, DK-5230 Odense M, Denmark Yngve Ohm (47), Departments of Physics and Chemistry, University of Florida, Gainesville, FL, USA... 

Per-Olov Lowdin and Yngve Ohm, Atomic, Molecular, and Solid-State Theory, Collision Phenomena, and Computational Methods. Proceedings of the International Symposium held at Flagler Beach, Florida, in 1978, in Int. J. Quantum Chem., Quantum Chem. Symp., No. 12, Wiley, New York, 1978. 

This artide is dedicated to Yngve Ohm for his contribution to electron propagator methods and their implementation for quantum chemical calculations. 

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