NIC Series Volume 25:   High Performance Computing in Chemistry edited by Johannes Grotendorst   ISBN 3-00-013618-5 December 2004, 160 pages   PDF

Over the last three decades the methods of quantum chemistry have shown an impressive development: a large number of reliable and efficient approximations to the solution of the non-relativistic Schrödinger and the relativistic Dirac equation, respectively, are available. This is complemented by the availability of a number of well-developed computer programs which allow of the treatment of chemical problems as a matter of routine. This progress has been acknowledged by the Nobel prize in chemistry 1998 to John Pople and Walter Kohn for the development of quantum chemical methods.

Nowadays, Theoretical Chemistry is widely accepted as an essential ingredient to research in a wide field of applications ranging from chemistry over biochemistry/biophysics to different flavors of material science: quantum chemical methods are indeed one standard tool at universities and research centres as well as in industrial research. The progress in experimental techniques is invariably complemented by an increasing demand for accurate quantum mechanical models as a means to analyze and interpret experimental data as well as to provide a deeper understanding of the results. On its own, the prediction of structures and properties of materials and individual chemical compounds or complexes is of great importance - either because the targets are experimentally inaccessible at sufficient accuracy or experiments are too expensive or impractical.

Currently quantum chemical methods are on the verge of being applied to realistic problems. Many research topics of considerable economical interest have quite demanding constraints: they require to model large numbers of particles (because the interesting properties require a certain minimum size of the model to be of use), the requested level of accuracy is achievable only within the realm of electronic structure methods or requires the time-resolved dynamics of the process in question. Additionally, it is observed that neighboring disciplines such as chemistry, biochemistry, biophysics, solid state physics and material science are gradually merging and in fact are sharing similar challenges and closely related methodologies. In view of today's complexity of software engineering and computer hardware these disciplines depend heavily on the support of computer science and applied mathematics. Thus, in the field of computational science an increasing amount of multidisciplinarity is not only beneficial but essential for solving complex problems.

Finally, we have to anticipate the tremendous development in the area of information technology both from the side of software as well as hardware development. In particular the emerging parallel computer and cluster systems open the road to tackle challenges of unprecedented complexity. However, method development must not only respond to the need of ever better and computationally less expensive (linear scaling) models but as well to the requirements of the underlying computer system in terms of parallel scalability and efficient usage of the (ever-changing) hardware.

Having in mind the wishes and requirements of the researchers in the NIC community and in the German chemical industry the most promising methodologies and quantum chemistry codes were chosen in order to push forward the development. The selected program packages TURBOMOLE, Quickstep, and MOLPRO cover complementary models and aspects of the whole range of quantum chemical methods. Within the project High Performance Computing in Chemistry (HPC-Chem) the functionality of these codes was extended, several important methods with linear scaling behavior with respect to the molecular size were developed and implemented, and last but not least the parallel scalability on modern supercomputers and cluster systems was substantially improved. In addition, for the treatment of solute-solvent interactions in quantum mechanical calculations the continuum model COSMO has been integrated into the aforementioned programs. This is of great relevance for the range of use since most practical problems are dealing with liquid phase chemistry.

I thank the HPC-Chem project partners and the industrial collaborators for their cooperativeness and the authors from the different research groups for their contributions to this book. Special thanks are due to Monika Marx, who invested time and effort defining the layout, correcting the figures, and designing the cover. The beauty of this volume is entirely her merit.

Jülich, October 2004
Johannes Grotendorst