Obiettivo 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. Campo scientifico natural sciencesphysical scienceselectromagnetism and electronicselectromagnetismnatural scienceschemical sciencesphysical chemistryquantum chemistry Programma(i) 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) Argomento(i) ERC-AG-PE4 - ERC Advanced Grant - Physical and Analytical Chemical sciences Invito a presentare proposte ERC-2010-AdG_20100224 Vedi altri progetti per questo bando Meccanismo di finanziamento ERC-AG - ERC Advanced Grant Istituzione ospitante UNIVERSITETET I OSLO Contributo UE € 2 017 932,00 Indirizzo PROBLEMVEIEN 5-7 0313 Oslo Norvegia Mostra sulla mappa Regione Norge Oslo og Viken Oslo Tipo di attività Higher or Secondary Education Establishments Contatto amministrativo Ingse Noremsaune (Dr.) Ricercatore principale Trygve Ulf Helgaker (Prof.) Collegamenti Contatta l’organizzazione Opens in new window Sito web Opens in new window Costo totale Nessun dato Beneficiari (1) Classifica in ordine alfabetico Classifica per Contributo UE Espandi tutto Riduci tutto UNIVERSITETET I OSLO Norvegia Contributo UE € 2 017 932,00 Indirizzo PROBLEMVEIEN 5-7 0313 Oslo Mostra sulla mappa Regione Norge Oslo og Viken Oslo Tipo di attività Higher or Secondary Education Establishments Contatto amministrativo Ingse Noremsaune (Dr.) Ricercatore principale Trygve Ulf Helgaker (Prof.) Collegamenti Contatta l’organizzazione Opens in new window Sito web Opens in new window Costo totale Nessun dato