MARVEL Junior Seminar — March 2021

Zoom meeting link:

https://epfl.zoom.us/j/93881551248
Password: 3417

The MARVEL Junior Seminars aim to intensify interactions between the MARVEL Junior scientists belonging to different research groups.

Each seminar consists of two presentations of 25 minutes each, allowing to present on a scientific question in depth, followed by time for discussion. The discussion is facilitated and timed by the chair.

MARVEL Junior Seminar Organizing Committee — Michele Kotiuga, Sara Fiore, Stefano Falletta, Kristians Cernevics and Patrick Mayor

Talk 1 —  Enrichment of hypothetical metal-organic framework databases for high-throughput computational screening

Sauradeep Majumdar, Seyed Mohamad Moosavi, Berend Smit
Laboratory of Molecular Simulation (LSMO), EPFL, Sion

By combining metal nodes and organic linkers, millions of metal organic frameworks (MOFs)  can be designed in silico. It is therefore important that when we make new databases of hypothetical MOF structures, we make sure that they not only contribute towards the required growth of the quantity of structures but also add new insights to existing databases. In this presentation, I will discuss about our recent work on designing a database of around 20000 hypothetical MOFs which are diverse in terms of their chemical design space - metal nodes, organic linkers, functional groups and topologies. We then assess the usefulness of these new structures by evaluating their performance in two important environmental applications - post combustion carbon capture and hydrogen storage. In each of the applications, we find that there still many structures lying in the unexplored regions of the material space which perform better than commercially available benchmark materials like Zeolite-13X- for post combustion carbon capture, and MOF-5 - for hydrogen storage.

Talk 2 —  Early stage solute clustering during natural ageing in Al-Mg-Si alloys

Abhinav C. P. Jain¹, Daniel Marchand¹, Albert Glensk^1,2, Michele Ceriotti², William Curtin^1
1 Laboratory for Multiscale Mechanics Modeling (LAMMM), EPFL
² Laboratory of Computational Science and Modelling (COSMO), EPFL

The Al-6XXX alloys are widely used in automotive applications for their high strength to weight ratio. The desired properties are achieved by precipitate hardening through the process of artificial aging at elevated temperatures. However, these alloys undergo natural aging at room temperature which is undesirable, and a mechanistic understanding of the early stages of precipitation in natural aging is still lacking. We perform off-lattice kinetic Monte Carlo simulations of vacancy migration using a near DFT-accurate machine-learning potential for Al-Mg-Si to study the dynamics of vacancy-solute interactions during natural aging. Early-stage clusters of Si and Mg atoms are found to trap vacancies, in agreement with indirect evidence for 'vacancy prisons'. The clusters and trapping times are studied qualitatively and quantitatively, and the implications of the early-stage kinetics on subsequent artificial aging is discussed.

Check the list of the next MARVEL Junior Seminars here.