Objective Quantum chemistry provides two approaches to molecular electronic-structure calculations: the systematically refinable but expensive many-body wave-function methods and the inexpensive but not systematically refinable Kohn Sham method of density-functional theory (DFT). The accuracy of Kohn Sham calculations is determined by the quality of the exchange correlation functional, from which the effects of exchange and correlation among the electrons are extracted using the density rather than the wave function. However, the exact exchange correlation functional is unknown—instead, many approximate forms have been developed, by fitting to experimental data or by satisfying exact relations. Here, a new approach to density-functional analysis and construction is proposed: the Lieb variation principle, usually regarded as conceptually important but impracticable. By invoking the Lieb principle, it becomes possible to approach the development of approximate functionals in a novel manner, being directly guided by the behaviour of exact functional, accurately calculated for a wide variety of chemical systems. In particular, this principle will be used to calculate ab-initio adiabatic connection curves, studying the exchange correlation functional for a fixed density as the electronic interactions are turned on from zero to one. Pilot calculations have indicated the feasibility of this approach in simple cases—here, a comprehensive set of adiabatic-connection curves will be generated and utilized for calibration, construction, and analysis of density functionals, the objective being to produce improved functionals for Kohn Sham calculations by modelling or fitting such curves. The ABACUS approach will be particularly important in cases where little experimental information is available—for example, for understanding and modelling the behaviour of the exchange correlation functional in electromagnetic fields. Fields of science natural sciencesphysical scienceselectromagnetism and electronicselectromagnetismnatural scienceschemical sciencesphysical chemistryquantum chemistry Programme(s) FP7-IDEAS-ERC - Specific programme: "Ideas" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013) Topic(s) ERC-AG-PE4 - ERC Advanced Grant - Physical and Analytical Chemical sciences Call for proposal ERC-2010-AdG_20100224 See other projects for this call Funding Scheme ERC-AG - ERC Advanced Grant Host institution UNIVERSITETET I OSLO EU contribution € 2 017 932,00 Address PROBLEMVEIEN 5-7 0313 Oslo Norway See on map Region Norge Oslo og Viken Oslo Activity type Higher or Secondary Education Establishments Administrative Contact Ingse Noremsaune (Dr.) Principal investigator Trygve Ulf Helgaker (Prof.) Links Contact the organisation Opens in new window Website Opens in new window Total cost No data Beneficiaries (1) Sort alphabetically Sort by EU Contribution Expand all Collapse all UNIVERSITETET I OSLO Norway EU contribution € 2 017 932,00 Address PROBLEMVEIEN 5-7 0313 Oslo See on map Region Norge Oslo og Viken Oslo Activity type Higher or Secondary Education Establishments Administrative Contact Ingse Noremsaune (Dr.) Principal investigator Trygve Ulf Helgaker (Prof.) Links Contact the organisation Opens in new window Website Opens in new window Total cost No data
