Post-doc offer M/F : Modeling bimetallic nanoparticles under oxidizing and reducing conditions

Job Description

Missions

The NACRE project focuses on the synthesis and characterization of bimetallic nanoparticles under oxidizing and reducing environments, using physical-based methods and advanced microscopy approaches under operando conditions as well as machine learning tools. Theoretical support of the experiments is provided by dedicated atomistic modeling, aiming to shed light onto the preferred structure, especially chemical ordering, or the extent of phase separation and solid solution, as a function of size, shape, possibly temperature and out-of-equilibrium (kinetic) conditions.

Activity

The work will focus on selected bimetallic systems of experimental interest, namely the Pd-Pt, Ag-Au, and Au-Pd systems. Existing many-body potentials (embedded-atom models [1], second moment approximation models [2]) will be employed to describe pristine nanoparticles, and their extensions to describe hydrides or oxydes will be considered based, on the very same framework [3] or by including a fluctuating charges component [4]. The parameters of these extended models will be determined from dedicated electronic structure calculations based on density-functional theory, on small particles. Then the potentials will be employed in large scale simulations (Monte Carlo, molecular dynamics) for nanoparticles comprising up to thousands of atoms, at finite temperature. Statistical analyses of the results will employ unsupervised machine learning tools, mostly for clustering the diversity of structural forms obtained in the simulations.

As a side part of the project, we will also address the possibility of simplifying configurational sampling, by reducing it to a lattice space, incorporating the off-lattice contribution that account for plasticity and vibrations effects into a surrogate many-body model of the neural network type. Machine learning will be employed here to simplify a harmonic description of these effects by providing the corresponding free-energy contribution based on the knowledge of the connectivity properties used as descriptors.

[1]X. W. Zhou, R. A. Johnson and H. N. G. Wadley, Phys. Rev. B: Condens. Matter Mater. Phys., 69, 144113 (2004)
[2]A. Rapallo, G. Rossi, R. Ferrando, A. Fortunelli, B. C. Curley, L. D. Lloyd, G. M. Tarbuck and R. L. Johnston, J. Chem. Phys. 122, 194308 (2005)
[3]Zhong W, Li Y S and Tománek D Phys. Rev. B 44 13053 (1991)
[4]F. H. Streitz and J. W. Mintmire, Electrostatic potentials for metal-oxide surfaces and interfaces, Phys. Rev. B 50, 11996 (1994).

Your Profil

Skills

The candidate should be familiar with basic programming in Fortran, C++, python being a plus. Expertise with electronic structure methods and conventional molecular simulation such as Monte Carlo, molecular dynamics, global optimization methods, will be appreciated. The work will also involve regular interactions with the experimental contributors to the project.

Your Work Environment

Grenoble offers a strong scientific background with many laboratories in physics, chemistry, engineering and biology, supported by nationwide facilities (synchrotron and neutron sources). Also offering a fantastic mountain landscape.

The LiPhy laboratory is a mixed research unit between CNRS and UGA, with a strong multidisciplinary character, both experimentally and theoretically, with 9 teams working on optical methods, soft matter, mechanics, chemical physics, statistical physics. The candidate will join the PSM team (statistical physics and modeling), the funding being provided within the project NACRE of the DIADEM PEPR program.

Compensation and benefits

Compensation

Between 3041€ and 4756€ raw, monthly depending on experience

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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