News

Honorary doctorate for prof. Weckhuysen on Dies Natalis

Every year on Dies Natalis, Ghent University awards various honorary doctorates. This year, one of the Honorary doctorates was awarded to prof. Bert Weckhuysen from the Utrecht University for his exceptional scientific achievements in the field of in-situ and operando spectroscopy in the field of heterogeneous catalysis. Honorary supervisors are Professors Veronique van Speybroek of the Center for Molecular Modeling and Kevin van Geem of the Laboratory of Chemical Technology both belonging to the Faculty of Engineering and Architecture. We are proud on our collaboration with his group, which proves how computational and experimental research is able to push boundaries in our fundamental understanding of processes on a molecular level and can help to develop sustainable chemical processes and future generation catalysts.

Professor Bert Weckhuysen is a leading professor in Inorganic Chemistry and Catalysis at Utrecht University. He is considered one of the founders of in-situ spectroscopy of heterogeneous catalysts. His research focuses centrally on the development of structure-activity relationships in the field of heterogeneous catalysis and materials science. This research also plays a major role in the path towards more sustainable chemistry. Professor Weckhuysen is strongly convinced that chemistry is the key to transforming towards a more sustainable society. Professor Weckhuysen's work has been awarded many scientific prizes and distinctions, including the Spinoza Prize, the highest scientific award in the Netherlands.

On March 21st, prof. Weckhuysen gave a public lecture ‘Towards a More Sustainable and Circular Society: Dreams Become Reality with Chemistry and Catalysis’.

Sources

Paper selected within the themed collection ‘Catalysis Science and Technology Most Popular 2023 Articles’

During summer 2023 Pieter Cnudde, Michel Waroquier and Veronique Van Speybroeck published a paper on ‘Universal descriptors for zeolite topology and acidity to predict the stability of butene cracking intermediates’ in Catalysis Science and Technology. This publication has now been selected in a themed collection of the most popular 2023 articles in Catalysis Science and Technology.

 

Figure taken from Catal. Sci. Technol., 2023,13, 4857-4872

The search for a proper catalyst with an optimal conversion, selectivity and lifetime is a topical research area in the transition toward a more sustainable chemical industry. Universal descriptors for (re)activity can be a powerful tool to predict the behavior of (new) catalyst materials a priori and therefore eliminating the necessity to perform expensive computational simulations or experiments. In this study, we investigated how the pore topology and acidity of zeolites influence the stability of intermediates upon alkene adsorption. We showed that relatively simple descriptors for acidity/topology allow to construct highly reliable linear relationships for determining the carbenium ion stability upon isobutene protonation. Our study highlights that identification of universal descriptors and construction of structure-activity relationships from advanced molecular dynamics simulations has the potential to accurately predict material properties in the field of zeolite catalysis.

For further reading: https://doi.org/10.1039/D3CY00642E

Two new PhDs at CMM

In the first half of November 2023 two of our PhD students successfully defended their PhD thesis. Underneath you can read a bit more on the work they did at CMM in the past years.

Congratulations Sander and YingXing!

Sander Borgmans

In-Depth Computational Characterization of the Structure and Dynamics in Covalent Organic Frameworks – Monday November 6, 2023

Supervisors: prof. Veronique Van Speybroeck and prof. Sven Rogge

Summary

Throughout history, mankind has demonstrated a remarkable ability to discover, manipulate, and develop materials to address the challenges of their time. Several decades ago, this ingenuity led to the development of nanostructured materials designed with atomic precision. Within this new class of materials, covalent organic frameworks are particularly interesting, endowing an enormous functionality given their internal pore architecture with molecule-sized pores and/or channels. In addition, they are rationally designed through a reticular building block process, allowing them to be tailored toward specific applications. However, this requires a fundamental understanding of their structure, and how this modular structure gives rise to certain properties. The aim of this PhD dissertation is therefore to construct reliable computer models for the structural characterization of covalent organic frameworks and the study of how their structural variations on the nanoscale can have macroscopic consequences. In this way, this research brings theory and experiment closer together, for which various techniques have been developed, or further extended, to enable molecular simulations that can deal with the complexities of these materials at the nanoscale.

YingXing Cheng

Development and Applications of the Frequency-Dependent Polarizable Force Field ACKS2ω – Monday November 13, 2023

Supervisor: prof. Toon Verstraelen

Summary

Van der Waals dispersion interactions are weak yet essential attractive forces critical in chemistry and physics, and their accurate representation remains a challenge in density functional theory (DFT). DFT is widely used for its computational efficiency but often fails to capture the full scope of these interactions, particularly type-C non-additive dispersion, which arise from long-range charge fluctuations, such as those in π-π conjugated systems. This limitation has prompted the development of various correction schemes to improve DFT’s performance, though these typically do not fully account for type-C dispersion.

To remedy the shortcomings in current models, this thesis proposes a novel approach leveraging the adiabatic connection fluctuation-dissipation (ACFD) theorem to capture correlation energies, including type-C dispersion interactions. The complexity of ACFD calculations necessitates a more practical solution, prompting the exploration of a frequency-dependent polarizable force-field method. Specifically, this research focuses on extending the atom-condensed Kohn-Sham DFT approximated to second order (ACKS2), creating a new model, ACKS2ω, which aims to efficiently compute long-range correlation energies using frequency-dependent induced charges and dipoles.

psiflow – modular and scalable active learning for interatomic potentials

Recently, we launched psiflow v2.0.0. Psiflow is a modular and scalable library for developing interatomic potentials. It uses Parsl to interface popular trainable interaction potentials with quantum chemistry software, and is designed to support computational workflows on hundreds or thousands of nodes. Psiflow is designed as an end-to-end framework; it can orchestrate all computational components between an initial atomic structure and the final trained potential. Using a variety of active learning approaches, the system's phase space is efficiently explored without requiring ab initio molecular dynamics.

Its features include:

  • active learning algorithms with enhanced sampling using PLUMED
  • Weights & Biases logging for easy monitoring and analysis
  • periodic (CP2K) and nonperiodic (NWChem) systems
  • massively parallel execution on thousands of nodes
  • efficient GPU molecular dynamics using OpenMM
  • supports the latest equivariant potentials such as MACE and NequIP

In addition, psiflow features a modular and concise API in which arbitrarily large workflows can be formulated, which can then be executed on a large number of different execution resources, including clouds (e.g. Amazon Web Services, Google Cloud), clusters (e.g. SLURM, Torque/PBS, HTCondor) and even container orchestration systems (e.g. Kubernetes). Visit the psiflow documentation for more details.

Sven Rogge awarded an ERC Starting Grant STRAINSWITCH

Sven Rogge has been awarded a Starting Grant 'STRAINSWITCH' by the European Research Council (ERC). With this grant, he is poised to establish his research team at the CMM, with a focus on computational materials modelling.

Given enough time, diamonds transform into graphite. Similarly, many materials around us have the intriguing ability to switch between different solid-state phases, thereby changing their macroscopic behavior such as colour, conductivity, and adsorption capacity. While it is straightforward to observe such phase transformations, it remains highly challenging to control under which conditions of temperature, stress, and guest adsorption they take place. In ‘STRAINSWITCH: Strain engineering to design functional 4D polymorphism in nanostructured materials’, Sven and his research team aim to develop computational models that predict how both atomic-level modifications and phase transformations deform the material and, thus, induce strain fields. These strain fields–areas where the material gets stretched or compressed–are key to understanding how atomic-level modifications and phase transformations interact. This could open the door to rationalising nanostructured materials design for sustainable applications in photovoltaic devices or water harvesters, among others.

ERC Starting Grants are designed to fund talented early-career scientists who are ready to work independently and show potential to be a research leader. In their 2023 call, 400 ERC Starting Grants were awarded, including five granted to researchers at Ghent University.

Researchers specialising in developing and applying computational modelling tools for nanostructured materials who wish to be part of Sven’s research team are encouraged to apply through this page.

Multiple ERC-funded Ph.D. and postdoc positions in strain engineering

 

The Rogge group, embedded within the multidisciplinary Center for Molecular Modeling (molmod.ugent.be) at Ghent University, Belgium, is looking for highly motivated researchers to perform state-of-the-art computational research in functional nanostructured materials design. These positions fit within a recent Starting Grant (StG) STRAINSWITCH awarded to prof Sven M. J. Rogge by the European Research Council (ERC). This grant aims to establish strain engineering as a new in silico approach to designing functional nanostructured materials such as metal-organic frameworks and metal halide perovskites (see, e.g., doi.org/10.1016/j.matt.2023.02.009). We especially welcome candidates with a strong track record who are – or may become – eligible to apply for a prestigious Ph.D. fellowship at our national funding agency or wish to prepare for a European fellowship.

More info about STRAINSWITCH and the different research topics within this ERC StG project

It is often easy to observe the ability of polymorphic materials to undergo a phase transition through changes in colour, conductivity, photovoltaic efficiency, or other functional properties. In contrast, it is challenging to control under which external stimuli, such as stress, temperature, or adsorption, these materials switch. Yet, enabling such polymorphic materials design would be a game changer for pressing societal challenges, from access to drinking water to producing green energy. However, this requires a firm understanding of how changing a material’s structure impacts its polymorphism and macroscopic function.

STRAINSWITCH aims to transform polymorphic material design by establishing the strain engineering concept. The central characteristic of this in silico approach is strain: the extent to which a material deforms due to external or internal triggers. On the one hand, external stimuli generate strain, even before they activate a phase transition. On the other hand, spatial disorder in a structure, tuneable from the atom to the device scale, also induces strain which interferes with external strain fields. Our fundamental idea is that it is possible to systematically predict which disorder is needed to ensure polymorphism only occurs under well-defined external triggers by balancing these internal and external strain fields.

Our research will initially focus on four distinct areas. We are recruiting candidates in each area:

  1. Developing the strain engineering workflow and establishing strain fingerprints for bulk disorder;
  2. Developing state-of-the-art interatomic potentials, including machine-learning potentials and coarse-grained force fields, to model long-range and interfacial disorder;
  3. Developing an open-source molecular dynamics algorithm to mimic the influence of general tensorial stress on polymorphic materials;
  4. Developing an in silico nuclear magnetic resonance spectroscopy toolbox to model amorphous structures.

Don't hesitate to contact prof Rogge (Sven.Rogge@UGent.be) for informal inquiries or more information.

More info about the CMM                        

The CMM groups about 40 researchers from the Faculty of Science and the Faculty of Engineering and Architecture at Ghent University with molecular modelling interests. It is unique in the university as it clusters computational researchers with various backgrounds, from multiple departments and faculties. The CMM aims to model molecules, materials & processes at the nanoscale by bringing together physicists, chemists, and (bio-)engineers while stimulating collaborations across disciplines. This multidisciplinary collaborative mission is the DNA of the CMM and is crucial in achieving scientific excellence in molecular modelling.

The CMM focuses on frontier research in six primary areas: computational material research on the nanoscale, model development, spectroscopy, many-particle physics, chemical kinetics in nanoporous materials, and bio-organic & organic chemistry. Our research is performed within a strong network of partners at Ghent University and at an (inter)national level. To pursue excellence, we strongly stimulate interactions between the various researchers in our team and our vast network of national and international partners. The prospective candidates will join a strongly connected research team and collaborate with national and international academic partners. The research of the CMM is internationally regarded to be at the forefront of its field.

Who are we looking for?

We are looking for highly motivated and creative Ph.D. candidates and postdoctoral researchers with: 

  • (for Ph.D. candidates) a Master’s degree or an international equivalent in physical chemistry, chemical physics, condensed matter physics, statistical physics, theoretical physics, or a related field obtained before your first working day at the CMM. Students obtaining their Master’s degree in the summer of 2024 are also eligible; 
  • (for postdocs) a completed Ph.D. in any of the abovementioned fields obtained before your first working day at the CMM;
  • demonstrated experience with coding (Python, C, etc.) and quantum chemistry software (Gaussian, VASP, CP2K, etc.) or force-field-based simulations is an advantage (for Ph.D. candidates) and a requirement (for postdocs);
  • a strong interest in molecular modelling;
  • excellent research and scientific writing skills;
  • perseverance and an independent, proactive working style;
  • the willingness to look beyond the borders of your discipline and a solid motivation to work in a multidisciplinary team;
  • high-level written and oral English communication skills with the ability to represent the research team effectively internally and externally, including presenting research outcomes at national and international conferences;
  • above all, the ambition to be at the forefront of in silico nanostructured materials design.

What can we offer you?        

A fixed-term contract (4 years for Ph.D. candidates, 18 months for postdoctoral researchers) with an attractive salary. The selected candidates will moreover get the ability to strengthen their CVs within the context of a strongly motivated and multidisciplinary research team and have the ability to contribute to challenging topical research to solve critical societal questions. They will have the opportunity to attend various international conferences and to include research stays in prominent international research teams in this field. Ghent University boasts a strong community that offers a broad range of training and career possibilities for Ph.D. candidates and postdoctoral researchers. The training opportunities focus on research and transferrable skills such as time management, presentation, and leadership skills.

How to apply?

We intend to fill these positions as soon as possible, preferably in January 2024. Complete applications will be considered on receipt, with interviews occurring on a rolling basis until the positions are filled. Interested candidates are requested to prepare the following documents:

  1. the filled out application form (see 2023-09_ApplicationForm_ERC_SR.docx underneath);
  2. a one-page cover letter/motivation letter explaining your interest in these positions and how you fit into the profile;
  3. a curriculum vitae;
  4. copies of the relevant diplomas (Bachelor’s, Master's, and/or Ph.D. certificate) and transcript (certified record of entire enrollment history at educational school), all merged together. Diplomas and transcripts not in Dutch or English should have an official translation in English.

The files should be saved as PDF and named as follows:

Application_STRAINSWITCH_[PhD/PostDoc]_[YourName]_[FileNumber1-4AsListedAbove]

In one mail, these documents should be sent to Sven.Rogge@UGent.be with the subject “Application STRAINSWITCH YourName”.

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Summer 2023 = 4 CMM PhDs

During last summer four of our young researchers successfully defended their PhD. Underneath you find an overview of their research topics.

Congratulations Michael, Ruben, Liesbeth and Alexander!

Michael Freitas Gustavo

New tools for high-dimensional, expensive, black-box global optimization functions applied to ReaxFF parameterizations – Thursday June 29th, 2023

Supervisor: prof. Toon Verstraelen

Summary

This work is seized with improving methods for solving high-dimensional, expensive, and black-box (HEB) global optimizations; particularly in the context of ReaxFF parameterization. We broadly discuss the fundamental difficulties of such optimizations and the most recent algorithms in literature to tackle them. We illustrate how the parameterization of scientific empirical models is often an example of HEB optimization. Of particular interest for this work is the reactive force field, ReaxFF, which we discuss in the context of computational chemistry more broadly. Finding good parameters for ReaxFF force fields is an underserved but important area of study. As an improvement, we introduce an optimization framework, GloMPO, which uses a novel management and control structure to guide global optimization routines. We demonstrate that this approach, compared to standard optimizers, is able to identify better minima and makes more efficient use of computational resources. Due to its modular structure, GloMPO can be configured in many different ways and offers several qualitative advantages to practitioners. Next, we present a set of sensitivity analysis tools which identify the most important parameters of a ReaxFF loss function. The methods we use are based on the state-of-the-art Hilbert–Schmidt independence criterion (HSIC). The results allow users to identify insensitive parameters, and greatly reduce the dimensionality of the optimization problem. This allows optimizers to identify good parameter values, faster, and with less overfitting than without sensitivity treatment. Both of our toolkits have been fully integrated into publicly available commercial software. They have been shown to improve ReaxFF parameterizations and are also flexible enough to be applied to other HEB problems.

Ruben Goeminne

Development of accurate and reliable methods for in silico modeling of adsorption in nanoporous materials – Monday July 10th, 2023

Supervisor: prof. Toon Verstraelen

Summary

Metal-organic frameworks (MOFs) are a class of materials that have in recent decades attracted widespread scientific interest. When it became clear that these MOFs could maintain a permanent porosity and huge internal surface area, they were quickly identified as ideal materials for gas adsorption and separation applications. Most strikingly, applications such as the capture of carbon dioxide from industrial smokestacks or the production of water from desert air can be made possible by these materials. However, the gigantic structural diversity of these materials and their inherent flexibility complicates the experimental characterization of their adsorption properties. Therefore, in this doctoral research, advanced computational techniques were developed to computationally determine the adsorption properties of these materials. This work was approached in two ways. On the one hand, methods were developed to more accurately describe the interaction of adsorbates with these MOFs; both by improving traditional force fields, and employing machine learning techniques trained on highly accurate quantum mechanical calculations. On the other hand, methods were developed to efficiently predict the remarkable flexibility of these MOFs during gas adsorption.

Liesbeth De Bruecker

Spectroscopic Fingerprint of Electronic Excitations in Nanoporous Frameworks and Transition Metal Complexes – Tuesday August 29th, 2023

Supervisor: prof. Veronique Van Speybroeck

Summary

Electronic excitations are located in the ultraviolet and visible part of the electromagnetic spectrum. Using spectroscopy it is possible to study the interactions between electromagnetic waves and matter. However, this experimental technique does not always allow to fully unravel the spectra. To gain more insight, therefore quantum mechanical computational techniques based on density functional theory are used. In this doctoral thesis, the spectroscopic fingerprint of heterogeneous catalysts and transition metal complexes is studied. When looking for environmentally friendly catalysts, the study of electronic excitations can help to find suitable materials for specific applications. The spectroscopic properties of transition metal complexes can provide insight into the nucleation process of nanoporous lattices. This research shows that computer simulations can provide complementary information to experimental work, which ultimately leads to more efficient materials research.

Alexander Hoffman

Unraveling Phase Transformations and Reactivity in Functional Nanostructured Materials Using Computational Vibrational Spectroscopy – Thursday August 31st, 2023

Supervisor: prof. Veronique Van Speybroeck

Summary

Realizing sustainable solutions for societal challenges such as energy production, production of chemicals or capturing greenhouse gases requires the development of new materials with adapted functionalities. In that respect, functional nanostructured materials are very interesting, as their material properties, which strongly depend on the structure on an atomic scale, can be tailored to the specific application. Before these new materials can be used in practice, they must first be thoroughly characterized. To this end, a wide range of spectroscopic techniques are available that investigate the structure of materials through their interaction with radiation. The resulting energy spectrum is often complex, which means that the interpretation is not always obvious. To identify the different spectroscopic signals, molecular simulations that make it possible to understand the microscopic structure of the material are often used. In this PhD, such simulations are used to explain vibrational spectra of functional nanostructured materials with the ultimate goal of understanding the origin of phase transformations and chemical reactions.

Congratulations dr. Massimo Bocus!!

On Friday June 23rd, 2023 Massimo Bocus successfully defended his PhD thesis ‘Towards State-of-the-Art Molecular Simulations for an Accurate Modeling of Intricate Zeolite-Catalyzed reactions’. During his PhD research he was supervised by prof. Veronique Van Speybroeck.

Congratulations Massimo!

Summary of the PhD in laymen’s terms

Zeolites are ubiquitous catalysts in the chemical industry, playing a central role in oil refineries but also in newer and sustainable technologies, including biomass conversion and the conversion of CO2 to hydrocarbons. To understand their working mechanism thoroughly and assist experiments, molecular modeling can be used to investigate these crystalline microporous materials. Unfortunately, zeolite-catalyzed reactions are very complex at the atomic scale, where a multitude of factors can change the reaction outcome including (but not limited to) the presence of guest species, defects, active sites distribution and so on. In this thesis, we present a thorough investigation of several zeolite-catalyzed reactions with advanced molecular modeling techniques. We attempt to gradually improve the description of the working catalyst by first using techniques based on molecular dynamics, where the atoms can move around as they would do at realistic reaction temperatures. Additionally, we rely on state-of-the-art machine learning techniques to speed up our otherwise very computationally expensive simulations, showcasing how these allow for unprecedented insights in the reaction under study.

Veronique Van Speybroeck gives Hassel lecture 2023

With the Hassel lecture, the Department of Chemistry from the University of Oslo and the Norwegian Chemical Society (Norsk Kjemisk Selskap, NKS) highlight innovative research by a distinguished invited lecturer. This year, Veronique Van Speybroeck had the honor to head this yearly lecture organized in honor of Nobel Laureate Odd Hassel.

The first day, Thursday May 25th, the Hassel Lecture was targeted at a broad, non-expert audience. Within this talk Veronique illustrated how functional nanostructured materials for sustainable chemistry, nanosensing and clean energy can be modelled at operating conditions, mimicking as close as possible the experimental conditions to enable future technological solutions. She showed some of our recent endeavors to drastically extend accessible length and time scales in molecular modelling using machine learning techniques and molecular dynamics techniques.

The second lecture, Friday May 26th, was addressed to an audience that is more proficient in the area of molecular modeling. After setting the scene of accessible length and time scales in modelling nanostructure materials, Veronique explained how recently the field of Machine Learning Potentials (MLPs) is steadily making its entrance in the field of nanostructured materials. MLPs hold the potential to extend the accessible length and time scales while retaining quantum accuracy. However, the rise of Machine Learning methods does not make fundamental research on quantum mechanical methods to describe the electronic structure problem for challenging problems unnecessary. Indeed, a correctly trained MLP will at best be as accurate as the underlying quantum mechanical data on which it was generated.

Operando modelling functional nanostructured materials for sustainable chemistry, nanosensing and clean energy | Time and place: May 25, 2023 11:15 AM–12:15 PM, Science Library

From quantum mechanics to machine learning: Bridging length and time scales in modeling nanoporous materials at operating conditions | Time and place: May 26, 2023 11:15 AM–12:15 PM, Avogadro, Department of Chemistry

Various vacancies for PhD students available in the group of Van Speybroeck at the Center for Molecular Modeling

In the framework of several recently granted projects, various vacancies at the PhD level are available within the research group of Van Speybroeck at the Center for Molecular Modeling (http://molmod.ugent.be).

A general description of the research performed within the group of Van Speybroeck can be found here https://molmod.ugent.be/research-statement-veronique-van-speybroeck

Vacancies are available in the following research domains :

I. Bridging the gap between density functional theory and quantum tensor networks to accurately model strongly correlated nanostructured materials (DFT+TN)

This research is situated in a concerted research action between the Van Speybroeck group at the Center for Molecular Modeling (http://molmod.ugent.be) and the group of Frank Verstraete at the Quantum Group (https://quantumghent.github.io/). Furthermore external partners at CALTECH and the University of Munich are involved in the project. 

One of the biggest challenges in computational materials science is the accurate property prediction of nanomaterials exhibiting strong electron correlations, where the behavior is dominated by strong interactions. By merging quantum tensor networks (TN) with commonly used density functional theory (DFT) methods, new DFT+TN framework will be developed which will be applied on a series of technologically relevant nanomaterials. Materials of interest are perovskites having optoelectronic and photocatalytic applications, and metal-organic frameworks having sensing applications. 

Within this research action various PhD positions are available, which vary from very fundamental topics -  where tensor networks having crystal symmetries will be developed to be applicable to realistic materials -  to more application oriented subjects - where band structures will be determined for realistic materials from which effective Hamiltonians will be derived that can be solved with tensor networks. Depending on the interest of the PhD applicant, the research can be more oriented towards fundamental or application oriented research. The interested applicant, should have a strong interest in many-body physics and quantum mechanical methods for complex materials. The future PhD students will work on a very challenging new research direction set up between two groups of excellence namely the Quantum Group and the Center for Molecular Modeling. Furthermore the PhD students will have the opportunity to perform research visits at CALTECH and the University of Munich. 

II. Strain to stabilize metal halide PERovSkites: an Integrated effort from fundamentalS to opto-electronic applicaTions (PERsist).

This research is situated in the framework of a running interuniversity research project PERsist with experimental partners of the KULeuven (prof. Hofkens, Roeffaers; https://www.hofkenslab.com/) and UAntwerpen (prof. Bals, Van Aert, Verbeeck ; https://www.uantwerpen.be/en/research-groups/emat/)

From the application point of view, this project aims to develop novel opto-electronic materials with higher conversion efficiency and lower production costs to be used in medical and security scanners. Metal halide perovskites (MHPs) have emerged as high-performance semiconductors due to their strong absorption and emission in a broad spectral range and their ease of manufacturing. However their integration in opto-electronic devices is hampered by inherent stability issues. Within this project, we explore a new paradigm based on strain field engineering to stabilize the optically active phase under ambient conditions.  Our proof of concept results were published in Science, which has become a highly cited paper (https://doi.org/10.1126/science.aax3878). The project builds on the synergy between leading experts in high-end micro/spectroscopy & modelling of nanomaterials. The materials are synthesized and tested in devices at the group of prof. Hofkens (KULeuven), characterized by high-resolution Electron microscopy at the EMAT group of the University of Antwerp and modeled within the group of Van Speybroeck at the CMM. 

Within the framework of this project, we aim to develop methods to model realistic metal halide perovskites having length scales up to 50 nm. As quantum mechanical calculations are not feasible anymore on these long length scales, we will develop Machine Learning Potentials (MLPs) for complex Metal Halide Perovskites, having defects at the short and mid-range length scale. The MLPs will be used to simulate materials subjected to external strain from the nano- to the micrometer scale and to evaluate their stability of oxygen and water.  Using these tools, it is the aim to unravel the origin of enhanced stability by applying external strain fields and to evaluate in how far the materials remain stable under realistic operating conditions. 

The interested applicant should have a strong interest in technological applications, method development and simulations for real materials. The selected candidate will work in an emerging research field where MLPs are developed for complex materials. Within the CMM, various PhD students are investing strongly in this research area.  A few recent papers from the CMM, in this field are https://www.nature.com/articles/s41524-023-00969-x; https://doi.org/10.1021/acs.chemmater.2c01508.

The future PhD student will interact very often with the experimental partners who are part of the project.  

III. DEFect-engineering and machine learning MODeling of UiO-66 and its catalytic properties (DEFMOD)

This research is situated within the framework of a recently granted FWO research project between the group of Van Speybroeck (Center for Molecular Modeling) and the group of prof. Van Der Voort (COMOC, https://www.comoc.ugent.be/)

Within this project we aim to synthesize and characterize meticulously controlled defect engineered MOFs, to model and understand these defects from the nano- to the mesoscale with quantum accuracy (up to 50 nm) and to apply these for catalytic applications. From the computational side, we will develop within this project new models to construct defect engineered materials having spatial heterogeneities from the nano to the mesoscale. A close interaction loop will be set up to structurally validate the mesoscopic systems with experimental characterizations at various levels. For these atomistic models, we will develop machine learning potential based on underlying Density functional theory (DFT) training data generated on nanocells having dimensions less than 10 nm, which are representative for the simulation of mesoscaled systems with structural disorder up to 50 nm. The targeted MLPs need to cover the behavior of defective MOFs close and far from equilibrium including reactive events which occur during catalysis. The CMM has recently published some proof of concept papers to generate MLPs for realistic materials see for example: https://www.nature.com/articles/s41524-023-00969-x.

This research is thus embedded within a grand effort of the research group of Van Speybroeck to model materials at longer length and time scales while maintaining quantum accuracy. 

Diploma requirements

Master’s degree in the field of Physics, Engineering Physics or an equivalent master. Students who will graduate in the coming months can also apply. 

Job Profile

  • You are highly motivated to become an independent researcher and to contribute to important societal problems related to clean energy production, non-fossil based production of chemicals, design of materials for the next generation energy carriers,…
  • You have a strong interest for quantum mechanical methods applied to technological relevant materials.
  • You have a strong interest to develop, implement and apply new physics oriented models in material science.
  • You have a strong academic record showing your potential to become an excellent researcher.
  • You are able to work in a team and have a strong motivation to collaborate with other researchers within both the CMM and our network.
  • We are looking for candidates with a pro-active working style; willingness to look beyond the borders of his/her own discipline and a strong motivation to work in a multidisciplinary team.
  • Experience with quantum chemistry software (Gaussian, VASP, CP2K,…) and coding (Python, C, ...) is an advantage. For students without modelling experience we will provide active training during the first months.

What we offer

  • A PhD position for a period of four years. There will be an evaluation after one year. 
  • You will be embedded in a dynamic environment at the Center for Molecular Modeling and have plenty of opportunities to interact with fellow researchers. You will have many interactions with our partners involved in the projects. You will have access to state-of-the-art computer infrastructure at the Flemish High-Performance Computing Centre (VSC).
  • You will have the opportunity to follow a wide range of training and educational courses part of the Doctoral Schools program of the Ghent University.
  • You will have the ability to participate actively in various international conferences, perform international research stays at the most prominent universities worldwide with whom we collaborate to strengthen your skills.
  • Interested candidates will have the ability to also contribute to education of the CMM by giving exercise classes.
  • Van Speybroeck has a very strong track record in coaching PhD students, under her supervision ca 35 PhD candidates successfully defended their thesis. Most of them found jobs afterwards in industry, academia and have built very strong CVs during their time at the CMM.

How to apply

Interested candidates are requested to prepare the following documents (all in English) and send them to cmm.vacancies@ugent.be before June 15th, 2023 with ‘[Vacancies Spring 2023] *FirstName*_*LastName*’ as subject :

1. A complete application form. Download this form underneath. -- Saved as pdf and named as follows: 1_AF_*FirstName*_*LastName*

2. A motivation letter, including the preferred research topic. -- Saved as pdf and named as follows: 2_ML_*FirstName*_*LastName*

3. A curriculum vitae. -- Saved as pdf and named as follows: 3_CV_*FirstName*_*LastName*

4. Copies of the relevant diplomas and transcripts (certified record of full enrollment history at educational school). Diplomas and transcripts that are not in Dutch or in English should have an official translation in Dutch or English. -- Saved as pdf and named as follows: 4_DT_*FirstName*_*LastName*

Further information

If you are interested in one of these positions, you may always contact our project officer through cmm.vacancies@ugent.be for more information or any other question you would have.

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