Editorial: Recent Progress in Theoretical and Computational Chemistry

Abstract

Theoretical and Computational Chemistry has seen a remarkable development in the past decades. While it started as a discipline of a few experts in the 1960s, the field has grown enormously due to advances in computational resources and software packages. In addition to the dramatic increase in computer power, a wide range of methods with predictive capabilities such as density functional theory (DFT) turned out to be extremely valuable tools in the hands of those who understand the chemistry of the systems under study and the limitations of the methods. As a result, increasingly larger molecular systems are nowadays routinely studied and interpreted according to the fundamental principles of quantum mechanics, including studies of electronic structure and reactivity of complex molecular processes. At the same time, the development of new methods and density functionals continues to be a vibrant field of research in a sustained effort to develop reliable approaches for almost any problem in chemistry. The availability of user-friendly software packages has popularized the field well beyond the realm of theoretical and computational chemistry groups. Today, almost any experimental research group in the world has an active member, or close collaborator, involved in computational modeling. The software packages are so popular and easy to use that calculations can be performed even by researchers with very limited knowledge of the underlying theories or approximations involved in the computations. While the calculations are easy to run, the interpretation of the resulting data, the range of validity of the approximations involved, and the range of error of the calculations performed with these popular software packages are often difficult to assess even by experienced users. These difficulties are exacerbated by the rapid emergence of new methods, acronyms, and software packages for general-purpose applications. It is, therefore, essential to complement efforts in software development with a comprehensive literature on new and existing methods, readily accessible to graduate students and researchers with an interest in current advances in the field. The present issue of ChemPhysChem is devoted to recent progress in a wide range of areas of Theoretical and Computational Chemistry by world-leading experts, reflecting the broad scope and rapid development of the field. For example, methodological developments for the treatment of excited states, heavy element systems, and non-covalent interactions are included. Another main topic is the computation of spectroscopic properties such as Raman optical activity, hyperfine coupling constants, NMR parameters or two-photon absorption intensities. The computation of these more complex properties has emerged as a research area that is of outstanding importance for the interpretation of modern spectroscopic experiments. Many of the applied papers in this issue furthermore reflect a current trend to model multicomponent systems of increasing complexity. The theoretical treatment of such inorganic/organic/bio-hybrids, which often include phase boundaries and require descriptions with periodic-boundary conditions, needs new approaches for the description of the basic electronic structure and for handling a huge number of degrees of freedom—some of which have already been proposed. This issue of ChemPhysChem reflects all these developments and we hope that the reader will find this selection useful, enjoyable and stimulating for her or his own work. 1 1 1