Postdoctoral Position in atomistic simulations of diamond rain formation in icy giants

The research work will focus on the study of the reactivity of C/H/O planetary mixtures in the extreme conditions of icy giants' interiors using atomistic simulations.

Scientific background :

The chemistry of icy giants such as Neptune and Uranus has attracted great attention from the scientific community in the last three decades. The interiors of such planets are believed to be mainly composed of a dense fluid which is a mixture of water, methane, and ammonia. The extreme conditions of pressure and temperature (T>1000 K, and P>3 GPa) in icy giants imply complex chemical transformations that dictate many of these planets' chemical and physical properties. In this regard, the formation of diamonds and super ionic water (diamonds rain) from the planetary mixture has been invoked to rationalize the icy giants' luminosity and anisotropic magnetic field. The absence of direct astrochemical observation into the process, the difficulty in characterizing the transformation «in situ» from experiments due to the extreme conditions and chemical inhomogeneities, make atomistic simulations a valuable tool to get precious insights into the mechanism and free energies of the process.

The main objective of the post doc will be to explore the free energy landscapes underlying the kinetics and thermodynamics of the early steps of diamond formation from C/H/O planetary mixtures under extreme conditions (2000-4000 K, 10-100 GPa). This will be achieved by developing a protocol gathering an array of state of-the-art computational techniques: ab initio methods, molecular dynamics, enhanced sampling techniques (metadynamics, umbrella sampling) and machine learning interatomic potentials (MLIPs).

Details on the post-doc position :

The position is funded by the ANR (National Research Agency) JCJC project "Chemistry of Diamond Rain Formation" (CHEMRAIN). The contract will be for two years and will commence within the next six months. The post-doc position could be either junior (Ph.D. required) or senior (two years of post-doc experience required).



The research will be conducted under the supervision of Dr. Flavio Siro Brigiano at the "Laboratoire de Chimie Théorique" at Sorbonne Université in Paris, in close collaboration with Dr. Arthur France Lanord (PHYSIX, IMPMC, Sorbonne Université, Paris) and Prof. Sandro Scandolo (ICTP, Trieste). Further collaborations with the experimental groups of Dr. Silvia Pandolfi (PHYSIX, IMPMC, Sorbonne Université, Paris) and Dr. Alessandra Ravasio (LULI-Ecole Polytechnique, Paris) are foreseen.