Kimihiko Hirao - Böcker

Recently, accurate ab initio quantum computational chemistry has evolved dramatically. In particular, the development of multireference-based approaches has opened up a whole new area and has also had a profound impact on the potential of theoretical chemistry.The multiconfigurational SCF (MCSCF)/CASSCF method is an attempt to generalize the Hartree-Fock (HF) model and to treat real chemical processes, where nondynamic correlation is important, while keeping the conceptual simplicity of the HF model as much as possible. Although MCSCF/CASSCF itself does not include dynamic correlations, it provides a good starting point for such studies. There are three approaches to handling dynamic correlations. Beginning with the MSSCF/CASSCF wave function, they are the variational (MRCI), perturbational (MRPT) and cluster expansion (MRCC) approaches.This important book presents the most recent and important developments in multireference-based approaches and their applications. Its main purpose is to highlight essential aspects of the frontiers of multireference theory and provide readers with the fundamental knowledge necessary for further development.

This volume presents a balanced blend of methodological and applied contributions. It supplements well the first three volumes of the series, revealing results of current research in computational chemistry. It also reviews the topographical features of several molecular scalar fields. A brief discussion of topographical concepts is followed by examples of their application to several branches of chemistry.The size of a basis set applied in a calculation determines the amount of computer resources necessary for a particular task. The details of a common strategy — the ab initio model potential method — which could be used to minimize such a task are revealed in the subsequent contribution. Such an approach is applied to atoms, molecules and solids. Two chapters are devoted to the prediction of solvent effects in biological systems. These effects are significant for interactions of nucleic acid bases and crucial for an evaluation of the free energies that govern the associations of macromolecules in aqueous solutions.A chapter on the developments and applications of the multireference Moller-Plesset method could be used as a reference in theoretical studies of systems where both the dynamical and nondynamical correlation effects should be accounted for. This technique is an efficient tool in such investigations. An explosive application of computational techniques — studies of detonation initiation and sensitivity in energetic compounds — is discussed in detail in the last chapter. The computational treatment of such unstable compounds allows the prediction of their crucial properties without being subject to their destructive forces.