Molecular electronic structures : an introduction

The present book is an introduction to molecular electronic structural theory. It is aimed at students who have reasonable familiarity with differential and integral calculus and are beginning a study of the physical description of chemical systems. We have decided to concentrate on the description of ground state electronic structures, or, in other words, the principles of chemical bonding in molecules. In this important respect the present volume differs from our earlier book "Molecular Orbital Theory" (Benjamin, 1964), which included a strong emphasis on the description of electronic excited states. In our treatment of molecular wave functions we make use of "symmetry operators", the latter being operators that leave the Hamiltonian unchanged. By using such symmetry operators, it is possible to characterize the electronic structures of molecules. In our opinion, this approach provides good preparation for later studies that may be undertaken in which formal group theory is employed. The heart of the book is Chapter 4, where we discuss in some detail the bonding in several selected molecules. Examples from both organic and inorganic chemistry are included in an attempt to make the coverage as general as possible. Our objective here is to provide an introduction to molecular bonding that will serve as a foundation for more advanced study of electronic structures. Suggested reading and problems are included in each chapter. Some of the problems are challenging, but working them will give the student a much better feeling for the principles involved. The suggested reading is of two types, books (and reviews) and original papers. And we urge students to examine at least some of the older papers in the field, as muck can be learned from them

Postscript: A Cinema of Liminality

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Prospective Memory in Older Adults : Where We Are Now and What Is Next

M. Kliegel acknowledges financial support from the Swiss National Science Foundation (SNSF).Peer reviewedPostprin

Magnetic excitations in vanadium spinels

We study magnetic excitations in vanadium spinel oxides AV$_2$O$_4$ (A=Zn, Mg, Cd) using two models: first one is a superexchange model for vanadium S=1 spins, second one includes in addition spin-orbit coupling, and crystal anisotropy. We show that the experimentally observed magnetic ordering can be obtained in both models, however the orbital ordering is different with and without spin-orbit coupling and crystal anisotropy. We demonstrate that this difference strongly affects the spin-wave excitation spectrum above the magnetically ordered state, and argue that the neutron measurement of such dispersion is a way to distinguish between the two possible orbital orderings in AV$_2$O$_4$.Comment: accepted in Phys. Rev.

Age differences in prospective memory for everyday life intentions : A diary approach

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