The Computational Chemistry Project Overview
Enrico Clementi is responsible for the Computational
Chemistry Project. E. Clementi headed the IBM Kingston (USA) Center for
Scientific and Engineering Computations, at IBM Kingston. Part
of the present research program continues activities which were started there.
The scientific expertise of the projects is listed below:
Determination of the reaction rate of chemical processes (in gas phase),
through the computing of the reaction surfaces. The reaction surfaces are
obtained by quantum mechanics calculations, either ab-initio or semi-
empirical. According to the approximation used, the reaction surface can be
calculated either at a qualitative level, or with an accuracy of the order of
one kilo calorie. With the transition state theory, one obtains reaction rate
constants with very accurate values for systems with a few atoms, less
accurate for systems with many atoms of for reactions occurring in solution.
Such research is of particular importance for the chemistry of combustion
and for the study of the reaction rate of polluting products, such as nitrogen
oxides. As it is known, combustion chemistry also includes the study of
flames, their thermic, dynamic and kinetic characteristics, etc.
Mathematical models for engineering of processes, generally of
phenomenological character, are used in order to simulate the behaviour of
either some industrial machinery or a whole plant. Mathematical models are
useful in planning (taking into account the characteristics of production),
simulating (enabling to foresee the evolution of the process, whenever the
operative conditions vary, including the possibility of extraordinary events),
optimizing (looking for the most favourable operative conditions),
controlling (by imposing a specific dynamic behaviour to the process),
monitoring (getting the state variables from easy-to-make measurements).
Our group of chemical engineers has a deep knowledge of basic chemical-
physical processes, and expertise in the description of industrial processes in
mathematical terms, in deriving from experimental or theoretical data the
parameters necessary to the modelling.
Researchers from both the CC and the CBB
Projects have expertise in quantum mechanics
calculations, such as Hartree-Fock, Dirac-Fock, many-body correlations
using perturbative methods (MP2, MP4) or variational methods
(configuration interactions, CI, multiconfigurations, MCSCF, etc.), density
functionals (Kohn-Sham, Wigner, etc.). The program used for the above
mentioned techniques are generally written by our research fellows, but at
times, they have been developed from national and international research
centers with which we collaborate.