|Specific scientific objectives for this project are :development of methods and software with emphasis on vector and parallel processing;development of graphics and visualising techniques;.development of methods for the study of large molecules and molecular materials;.design of pharmaceutical products and related systems;.information on the activation of inert substances by metal centres and surfaces;.information on the reversible transfer of electrons for molecular energy storage facilities;.improvement in the methods of study of highly reactive or short-lived species in gas and liquid phases;.model and experimental studies of energetic and entropic control of covalent and non-covalent single and multisite molecular interactions;.improvement of methods for treating complex reaction systems (e.g. combustion and atmospheric chemistry);.improvement of the theoretical approaches and beam experiments for the investigation of state specific processes;.improvement in ab initio methods for handling electron correlation in arbitrary electronic states and in efficient calculations of potential energy surfaces;development of new techniques for the modelling of molecular aggregates, co-ordination compounds and organometallic systems.Current statusThe characteristic of the D3 Action of the COST Chemistry is to promote co-operation among European scientists in pursuing basic research into the theory and modelling of chemical systems at the microscopic level. The application of standard procedures for the solution of problems is not a focus of the D3 activities but rather the development of new theoretical concepts and numerical technologies.To promote new activities in the frame of the COST Chemistry D3 Action and to help the Management Committee in determining future trends in the theory and modelling of chemical systems and processes, two Workshops were organised in Pisa (I) on 14/17 Apr 1996 and in Lyon (F) on 5/7 Sep 1996. The workshops succeeded in bringing together the leading European scientists in the field of theory and modelling of chemical systems and processes and in promoting lively discussions among the participants.All the participants have emphasised the role that the COST Action D3 has to play in :promoting the establishing of a research network on a true European scale by selectively supporting short and planning visits;singling out the most promising and productive research lines by promoting meetings on 'hot topics' and future-trends analysis; advising national and community research fund administrators in channelling resources.Specific trends in European research were agreed to be :finding synergism between different theoretical methods;progress in understanding reaction mechanism at microscopic level by developing techniques aimed at determining realistic potential energy surfaces and performing accurate dynamic calculations;extending the theoretical work from the gas phase to include solvent effects, surface phenomena, catalytic actions, condensed phase properties.Suitable means to facilitate the above mentioned trend are :establishing robust European teams of researchers to work in the same area in a synergic way;favouring exchange of young scientists (post-docs) and PhD students to spread new technologies and increase scientific expertise;protecting scientific software and creation of a parallel market (separate from commercial ones) to encourage development, integration and circulation of scientific software among European scientists;promoting "brain storming" sessions and workshops, bringing together experts from a given field to push scientific progress.The projects accepted so far by the Management Committee (including the six proposals inherited by the PECO program) reflected the broadness of the field. These projects are :computer modelling of co-ordination compounds, organometallic and inorganic systems; structure, spectroscopy and reactivity;molecular modelling to target scientific functions : ground and ionised states;treatment of classical and quantum degrees of freedom in molecular dynamics simulations by the method of density matrix evolution;modelling and theoretical parameters of systems containing nitric oxide;structure rearrangements and fragmentation of organic ion-molecule complexes;accurate calculations of the reactive properties of small molecules for the purpose of modelling gas phase systems;development and application of quantum and stochastic density matrix and density functional approaches to the correlation, relaxation and relativistic effects on the structure and properties of atoms, molecules and crystals;charge sensitivity concepts for molecular structure and chemical reactivity; theoretical development and applications to catalytic and biological systems;theoretical and low temperature vibrational spectroscopic studies of organometallic compound and their unstable complexes with small ligands;a novel approach to chemical structures : quantum mechanical and algebraic treatments;.development of new quantum chemical methods and the accurate calculation of molecular properties of small and medium-sized molecules;.intelligent software in computational chemistry : the Open Mol project;. dynamic modelling of stability and fragmentation in large ionic clusters;structural and dynamic properties of liquid crystalline materials.The scientific evaluation of the results obtained, and an assessment of the benefit of the collaboration and the transfer of research results into practical applications will be performed in July 1997 by two external referees (a well-known expert in the field and an industrial chemist) and two internal referees from the Technical Committee COST Chemistry, on the basis of final reports, joint publications and oral presentations, during the final workshop in Perugia (Italy), 28 Jun/2 Jul 1997. As COST Action D3 will end on 9 September 1997 (five years after the signing of the MoU), it is likely that projects of the Action will evolve into the COST Action D9 "Advanced Computational Chemistry of Increasingly Complex Systems".