II. Molecular modelling of heavy elements

1) Modelling in bulk solutions and at interfaces

Our group develops polarizable force-field models (including many-body effects, such as charge-transfer, hydrogen bonding, etc.) to characterize the dynamics by classical molecular dynamics (Polaris(MD) package http://biodev.cea.fr/polaris/) of radioelements in bulk solution or at interfaces (organic/inorganic) (F. Réal, A. S. P. Gomes, Y. O. Guerrero Martínez, T. Ayed, N. Galland, M. Masella, and V. Vallet, J. Chem. Phys. 144, 124513 (2016) [doi:10.1063/1.4944613], F. Réal, M. Trumm, B. Schim- melpfennig, M. Masella, and V. Vallet, J. Comput. Chem. 34, 707 (2013) [10.1002/jcc.23184]). This work of relevance for medicine and the nuclear cycle (liquid/liquid separation processes) involves our  partners from CEA Saclay (M. Masella, DSV), CEA Marcoule (E. Acher, D. Guillaumont, Lab LILA). 

2) Radioelements and nuclear safety

The predictive modeling of the nature and amounts of radioactive, such as Ru or Pu oxides  species that might be released in volatile forms in case of a nuclear accidental is of key importance for nuclear safety agencies and risk analysis. Our group uses highly accurate quantum chemical methods (multi-reference ones, if needed, eg. CASSCF, CASPT2, DMRG), and developed in the PCMT team (EOM-CCSD), to provide reliable and accurate chemical and thermodynamic properties of gaseous radioactive species. (eg. F. Miradji, F. Virot, S. Souvi, L. Cantrel, F. Louis, and V. Vallet, J. Phys. Chem. A 120, 606 (2016) [DOI: 10.1021/acs.jpca.5b11142]) 

3) Spectroscopic properties

We use electronic structure methods different degrees of accuracy (EOM-CCSD, CASPT2, DFT, …) to characterize how molecular species interact with electromagnetic radiation, which is the basis for different spectroscopic approaches (IR/Raman, UV-Vis, Fluorescence, XAS, XPS, NMR,…).  These studies are performed for species the gas phase or in condensed phase (where we combine different methods via quantum embedding approaches). Our aim is to provide models that can help us connect experimental observation to physical processes occurring at the nanoscopic scale (A. S. P. Gomes, C. R. Jacob, F. Réal, L. Visscher, and V. Vallet, Phys. Chem. Chem. Phys. 15, 15153 (2013) [doi: C3CP52090K] ; P. Lindqvist-Reis, F. Réal, R. Janicki, and V. Vallet, Inorg. Chem. 57, 10111 (2018) [doi: 10.1021/acs.inorgchem.8b01224]) 

Structural models for the calculation of the excitation energies of UO2Cl42- in a Cs2UO2Cl4 crystal