Emmanuel Fromager

Biography

Emmanuel Fromager has been full professor of quantum chemistry at the University of Strasbourg since 2019; he directs the Laboratory of Quantum Chemistry (LCQS) within the Strasbourg Institute of Chemistry (IC). His research focuses on the development of electronic structure theories, with a particular emphasis on strong electronic correlation and excited states.

Professor Fromager graduated from the National Higher Institute of Aeronautics and Space (ISAE-SUPAERO) based in Toulouse, France, in 2002. In 2005, he defended his doctoral thesis under joint supervision (Toulouse and Stockholm, Sweden) on method development in relativistic quantum chemistry and applications to actinide chemistry. After two postdocs in Scandinavia (two years in Odense, Denmark and one year in Tromsø, Norway) that were devoted to the development of multi-configuration density functional theory (DFT), he was appointed associate professor at the University of Strasbourg in 2008.

Emmanuel Fromager’s work is currently concentrated on two research topics, namely ensemble DFT of electronic excitations [E. Fromager, Phys. Rev. Lett. 124, 243001 (2020)] and quantum embedding theory [S. Sekaran, O. Bindech, and E. Fromager, J. Chem. Phys. 159, 034107 (2023)].

Fellowship 2024

Dates - 01/10/2024-30/09/2026

Project summary

NUCLEAR QUANTUM DYNAMICS COUPLED TO MANY-ELECTRON DENSITY-FUNCTIONAL ENSEMBLES: EXACT FORMULATIONS AND PRACTICAL APPROXIMATIONS

Performing accurate computer simulations of light-induced chemical reactions remains challenging, particularly when the molecular complexes under study are relatively large. This is because, in addition to the quantum description of the nuclei, which is in principle necessary, the electronic excitation processes that occur within the molecule must be adequately modeled.

On the one hand, density functional theory (DFT), which has become the method of choice in quantum chemistry and materials science, describes electrons in their lowest energy level (the so-called ground state). On the other hand, ensemble DFT (eDFT), which is a natural and in-principle exact extension of DFT to excited electronic states, seems to be the ideal candidate for extending DFT beyond the usual Born-Oppenheimer approximation, which cannot be applied to photochemical processes.

The aim of the project is twofold. Firstly, we aim to formulate a new and formally exact quantum theory of electrons and nuclei, in which an eDFT treatment of the electrons is coupled to a wave function description of nuclei. On this basis, we subsequently plan to identify and develop different levels of practical approximations (including hybrid quantum/classical approximations), and calibrate them on model systems. Our ultimate goal is to design new methods based on first principles for reliable large-scale simulations of photochemistry.