This volume contains nine contributions, from leading scientists, which embrace the fundamentals of various aspects of the conceptual development of quantum chemistry. Topics dealt with include the behaviour of molecules in magnetic fields, the long-standing problem of the decoupling of nuclear from electron motion in molecules, the status of density functional theory, and the string model of chemical reactions.

I would like to present to a wide circle of the readers working in quantum chem istry and solid-state physics, as, .ell as in other fields of many-body physics and its interfaces, this book deyoted to density functional theory written by my colleagues Eugene S. Kryachko and Eduardo Y. Ludena. Their ways to this theory are rather different although basically both of them are quantum chemical. Eugene S. Kryachko came to energy density functional theory from the theory of reduced density matrices, and Eduardo '. Ludena dewloped earlier the concept of loges in quantum chemistry. Neyertheless,...

A companion volume to Conceptual Trends in Quantum Chemistry, this work contains eight contributions focusing on important conceptual trends in atomic and molecular theory. The polarization between ab initio and semi-empirical methods is thoroughly analyzed in two of the articles, which also provide bridges between such procedures. Hydrogen-transfer theory and electron delocalization are treated in two further papers. Explicitly time-dependent descriptions of intermolecular dynamics, which constitute a characteristic trend in current research, are represented by an article about the quantum...

Looking at the literature, one finds that, in atomic and molecular physics, comparatively little interest has so far been devoted to the GHF scheme, and the purpose of this paper is to try to focus the interests of some quantum chemists to this rather interesting problem of looking for the "absolute minimum" of the original Hartree-Fock method. (P. -O. Li: iwdin and I. Mayer, Ref. 5, p. 93. ) In view of the complexity of quantum mechanical equations of motion describing atomic, molecular, and solid state phenomena - even when modelling very small systems at the nonrelativistic level within...

The rivers run into the sea, yet the sea is not full Ecclesiastes What is quantum chemistry? The straightforward answer is that it is what quan tum chemists do. But it must be admitted, that in contrast to physicists and chemists, "quantum chemists" seem to be a rather ill-defined category of scientists. Quantum chemists are more or less physicists (basically theoreticians), more or less chemists, and by and large, computationists. But first and foremost, we, quantum chemists, are conscious beings. We may safely guess that quantum chemistry was one of the first areas in the natural sciences...