Description du sujet de thèse

Electronic resonances are states that are unstable with respect to loss of electrons. Understanding physical processes involving resonances is crucial in many scientific fields, such as DNA breakdown by slow electrons, plasma chemistry, ultrafast X-ray spectroscopy, and in resonance ionization spectroscopy. Due to the complexity of the physical processes at play, accurate theoretical models are indispensable to help interpret experiments. As standard electronic structure theory methods cannot describe resonances due to the fact that their wave functions diverge in space, in recent decades methods based on non-Hermitian quantum mechanics, whereby complex-scaling is applied to the Schrödinger equation, have provided a way forward. Combined with coupled-cluster methods, these approaches have been used to model various types of electronic resonances such as temporary anions, Rydberg states, and core-vacant states, and different spectroscopies (among others, Auger spectra, photodetachment spectra, electron energy loss spectra), but they are currently inapplicable to situations in which relativistic effects are important, such as for valence properties of molecules containing heavy elements or for core spectroscopies involving elements beyond the second row of the periodic table. The goal of this thesis project is therefore to bridge this gap and combine non-Hermitian quantum mechanics and correlated relativistic electronic methods, such as those based on coupled cluster theory. These novel theoretical approaches will be employed to simulate resonances for species containing actinides and heavy halogens such as iodine, which are relevant both in the context of radioprotection, X-ray spectroscopies, and atmospheric chemical physics.

Contexte de travail

This thesis will be carried out in the framework of the ANR project SCREECHES and of a double diploma (cotutelle) between the University of Lille (supervisor: André Severo Pereira Gomes) and the Katholieke Universiteit Leuven (KU Leuven, direction: Dr. Thomas Jagau). The hired PhD candidate will consequently be required to spend a minimum amount of time in each institution as required by the regulations of the respective doctoral schools.

The thesis' research activities involve the development of novel molecular electronic structure methods and their implementation on codes such as DIRAC(https://diracprogram.org).

A background (undergraduate or masters degree) in Physics, Chemistry, Mathematics or Engineering is a requirement. Prior knowledge on quantum mechanics, molecular electronic structure methods and programming languages (C/C++/Fortran/Python) is highly recommended. Additional knowledge in best practices in programming (version control etc) and tools (Git, Cmake), or in treatment of data is a plus.

Beyond the research activities, the PhD candidate is expected to present their work through (oral) presentations in national or international scientific conferences and workshops. This implies the need for work-related travel, as well as good communication skills in english (level B2 or higher).

Contraintes et risques

The occupational hazards associated with this position are the same as those associated with office work, and mostly consist of exposure to computer screens.