51 results for diamond

Sep 22 2024

End of summer, and the start of a new academic year.

  • Filed under blog

  • September 22, 2024

Mid September in Hasselt means the start of a new academic year. It brings to an end a summer of doing some unrestricted research. Especially the last month has been extremely busy.

  • The DFT2024 conference in Paris from August 25th until 30th, where I presented our recent work on the GeV defect, which we will be submitting shortly.
  • The materiomics summer school, where I gave a lecture on performing practical quantum mechanical calculations,
  • The public PhD defense of Emerick Guillaume (QuATOMs group member) on the growth of diamond: congratulations Emerick!
  • A seminar at UNamur on “extreme machine learning”, discussing our work on small datasets and some of the work I did this summer on a spray coating dataset.

Today the first week of academic year ended, and I already had the pleasure teaching quantum mechanics and modelling courses to chemistry and materiomics students. We also welcome 2 MSc materiomics students to the group: Brent Motmans and Eleonora Thomas. Brent will be working on an experimental-theoretical project, where the theoretical side will focus on machine learning of his experimental data. Eleonora on the other hand will be combining DFT and machine learning in her study of diamond. A very warm welcome to the QuATOMs group for both.

 

Permanent link to this article: https://dannyvanpoucke.be/end-of-summer-and-the-start-of-a-new-academic-year/

Sep 01 2024

New QuATOMs group member

During the last year, Esin Aylin Melan worked hard at her MSc Thesis within the QuATOMs group. Her research focus was centered on the impact of strain on the zero-phonon-line of the GeV color center in diamond. This work she presented, together with Thijs van Wijk, at the SBDD conference in Hasselt, and was presented as well at both the BPS and EMRS spring meeting of 2024. Before the summer she gave her (very good and enthusiastic) final presentation of the MSc thesis results, bringing her first real research project to good end. (Paper will follow later 🙂 )

Recently, she also received the great news that she was awarded a bilateral PhD Scholarship between UHasselt & UNamur. So from September first, she has started working on the modeling of color centers in diamond and oxides for the coming four years. Welcome to the QuATOMs team, and congratulations on the scholarship. We look forward to the enthusiasm and insights you’ll bring to the team.

Permanent link to this article: https://dannyvanpoucke.be/new-quatoms-group-member/

Project: Augmenting DFT modelling of vibrational spectra through Machine Learning and Deep Neural networks using small data sets.

Thijs van Wijk, MSc. Physics’23
[Materiomics AAP-UHasselt, 2023-2027]

Quantum chemical modelling, specifically density functional theory (DFT) plays an important role in modern materials design, as it provides direct access to atomic scale properties not available experimentally. However, as the system size and complexity grows so does the computational cost of the DFT calculations. The aim of this project is to extend the range of problem sizes that can be investigated at DFT accuracy through the use of machine learning and deep neural networks. For this, methods will be developed focusing on the efficient learning from small data sets. This AI-enhanced DFT approach will be applied on the modelling of vibrational spectra for the fingerprinting of defects in diamond and the characterisation of weakly bonded crystals.

Acknowledgement financial/compute support

Permanent link to this article: https://dannyvanpoucke.be/ai-vibrations/

Lignin

Lignin is the second most abundant biopolymer on earth, after cellulose. Like cellulose it is present in all plant cells playing an important role in the structural stability of the cells. Its aromatic nature makes it  the largest potential source of renewable aromatic building blocks for polymer industry. The three most common polymeric building blocks are coniferyl (G), coumaryl (H) and synapyl (S) alcohol, which can be linked through various inter-unit linkages. This makes it a rather complex polymer (in contrast to standard polymers like polyethylene glycol (PEG) ) consisting of at least three possible building blocks and at least seven possible linkages. This makes the combinatorics of even small polymers rather daunting. As such, for a given molecular weight, a large number of possible polymer configuration are possible, while the polydispersity of lignin means a sample will consist of a distribution of polymer weights. This stands in stark contrast to materials like diamond, cerium-dioxide or even MIL-47(V), which have a unique atomic topology. As a result, theoretical (quantum mechanical) modeling of lignin has remained in its infancy, while experimental characterization has made it abundantly clear that the composition of “lignin”  depends on (1) the botanical source, it even depends on the part of the plant, and (2) the processing and extraction. As a result, there is a huge amount of experimental studies characterizing lignin, since each lignin sample is effectively unique and different. This also makes the use of lignin in applications very challenging due to the variation in starting material.

We therefor aim to shine a light on the atomic structure of lignin polymers and polymer-property relations, going beyond the standard empirical statistical observation of base unit fractions and aliphatic/phenolic hydroxide fractions. By means of exhaustive prototype studies and statistical general sampling a large data base is being constructed of property-structure relations at different levels of theory (going from force-fields to quantum mechanical modelling).

Projects

  1. DigiLignin [2022-2024, BioEconomy-FWO/EC]
  2. QuantumLignin [2024-2028, BOF-KP; 1 PhD]

Permanent link to this article: https://dannyvanpoucke.be/lignin/

QuATOMs group

Cover Journal Computational Chemistry 2013, Volume 34 Issue 5, Hirshfeld-I for periodic systems.

The Quantum & Artificial inTelligence design Of Materials (QuATOMs) group was launched in October 2022. It’s part of the research group of materials chemistry in the faculty of science at UHasselt, and embedded in the Institute of Materials Research (IMO-IMOMEC). It is an interdisciplinary computational materials research group with interest in both materials physics and materials chemistry.

The research of the QuATOMs group is organised around three pillars:

Cover Journal Computational Chemistry 2013, Volume 34 Issue 5, Hirshfeld-I for periodic systems.

1. Quantum Mechanical Modeling

(c.q. Density Functional Theory, DFT),
The quantum mechanical pillar focuses on the (high accuracy modelling of) electronic, vibrational, and geometric structure of materials, and the development of conceptual DFT methods for characterization of experimentally relevant properties such as reactivity, atomic charge and polarization. For these topics, the research builds on existing experience with dens solids like diamond and cerium-oxide, but also more soft hybrid materials (in particular Metal-Organic Frameworks, which present strong similarities to hybrid perovskites)  and molecular crystals.

 

Cover Polymer International: Machine learning on small data sets, application on UV curable inks.

2. Artificial Intelligence (AI) modelling using small datasets

The artificial intelligence pillar focuses on the development of machine learning algorithms that deal with very small datasets (<50 samples). These can be experimental or theoretical in nature (as these algorithms are data agnostic in general). Our aim is to further improve these models aimed at lab scale experimental materials optimization applications. In addition, we intend to extend the applications also in the area of DFT generated data, thus creating a computationally cheaper alternative or extension for our DFT modelling.

 

 

Cover image CrystEngComm 2015 Vol 17 Issue 453. Experimental-Theoretical collaboration for corroboration and elucidation of experimental results.

This third pillar brings the former two in contact with experimental reality. It is aimed as a proving ground for developed methods, as well as a contact point for experimental colleagues interested in computational corroboration and/or elucidation of experimental findings. Based on the range of materials dealt with in the past, this means support is available for a broad range of materials investigated within the departments of chemistry and physics: diamond in the context of growth, bio-applications, eutectic solvents for batteries, Metal-Organic Frameworks (and similar hybrid perovskites), bio-based polymers, …

 

These three pillars are intertwined with the central aim of developing methods for materials modelling and characterization, where the strengths of DFT and AI are combined to provided fast and high quality interpretation of experimental observations.

Group members

Current

Former

Research Projects QuATOMs

  1. QuantumLignin [BOF-KP: 2024-2028]
  2. AI-accelerated quantum mechanical modeling of the optical properties of semiconductor materials [BOF-BILA, UHasselt/UNamur, 2024-2028]
  3. Augmenting DFT modelling of vibrational spectra through Machine Learning and Deep Neural networks using small data sets. [2023-2027]
  4. DigiLignin: Digitization of lignin polyurethane development [Bio-Economy, 2022-2024]

Permanent link to this article: https://dannyvanpoucke.be/quatoms-group/

Dec 10 2023

Materiomics Chronicles: week 11 & 12

SnV split vacancy defect in diamond.

After the exam period in weeks nine and ten, the eleventh and twelfth week of the academic year bring the second quarter of our materiomics program at UHasselt for the first master students. Although I’m not coordinating any courses in this quarter, I do have some teaching duties, including being involved in two of the hands-on projects.

As in the past 10 weeks, the bachelor students in chemistry had lectures for the courses introduction to quantum chemistry and quantum and computational chemistry. For the second bachelor this meant they finally came into contact with the H atom, the first and only system that can be exactly solved using pen and paper quantum chemistry (anything beyond can only be solved given additional approximations.) During the exercise class we investigated the concept of aromatic stabilization in more detail in addition to the usual exercises with simple Schrödinger  equations and wave functions. For the third bachelor, their travel into the world of computational chemistry continued, introducing post-Hartree-Fock methods with also include the missing correlation energy. This is the failure of Hartree-Fock theory, making it a nice framework, but of little practical use for any but the most trivial molecules (e.g. H2 for example already being out of scope). We also started looking into molecular systems, starting with simple diatomic molecules like H2+.

SnV split vacancy defect in diamond.

SnV split vacancy defect in diamond.

In the master materiomics, the course Machine learning and artificial intelligence in modern materials science hosted a guest lecture on Large Language Models, and their use in materials research as well as an exercise session during which the overarching ML study of the QM9 dataset was extended. During the course on  Density Functional Theory there was a second lab, this time on conceptual DFT. For the first master students, the hands-on project kept them busy. One group combining AI and experiments, and a second group combining DFT modeling of SnV0 defects in diamond with their actual lab growth. It was interesting to see the enthusiasm of the students. With only some mild debugging, I was able to get them up and running relatively smoothly on the HPC. I am also truly grateful to our experimental colleagues of the diamond growth group, who bravely set up these experiments and having backup plans for the backup plans.

At the end of week 12, we added another 12h of classes, ~1h of video lecture, ~2h of HPC support for the handson project and 6h of guest lectures, putting our semester total at 118h of live lectures. Upwards and onward to weeks 13 & 14.

Permanent link to this article: https://dannyvanpoucke.be/materiomics-chronicles-week-11-12/

Sep 30 2023

Materiomics Chronicles: week 2

After the more gentle introductions last week during the first lectures at UHasselt, this week we dove into the deep end.

For the students of the second bachelor chemistry  the course introduction to quantum chemistry dove into the postulates of quantum chemistry. They learned about the wave-function and operators, had their first contact with the mystics notation of quantum chemistry: the bra-ket notation. For the third bachelor chemistry, the course quantum and computational chemistry was centered around perturbation theory. In addition to the theory, we applied the method to the simple system of the infinite square potential.

The electron density in the primitive diamond unit cell.

In the master materiomics the course fundamentals of materials modeling was kicked into high gear, not only did the students learn the theory behind quantum mechanical modelling, they also had their fist experience on the supercomputers of the VSC. So in addition to the road from the standard Schrödinger equation to the Hohenberg-Kohn-Sham equations of DFT, they also traveled their first steps along the road from their somewhat familiar windows OS to the bash command-line environment of the HPC unix system.

Finally, as the course introduction into quantum chemistry is part of the preparatory program of the master materiomics, I started creating the narrated versions of those lectures as well (2h worth recording, corresponding to 4h of live lectures). As the available time is limited, we are going for single shot recordings which makes things exciting in that department as well.

At the end of this week, we have added another 7h of live lectures and 2h of video lectures, putting our semester total at 19h of lectures. Upwards and onward to week 3.

Permanent link to this article: https://dannyvanpoucke.be/materiomics-chronicles-week-2/

Sep 17 2023

Countdown to Materiomics: Year 2

  • Filed under blog

  • September 17, 2023

Last year, we started a new masters program at Hasselt University called “Materiomics“. It is aimed at bachelor students in chemistry and physics who want to become the materials researchers of the future: interdisciplinary team players with experimental, theoretical, and computational skills ready to build anything made of atoms. There are four specialization tracks developed: Health, Energy, Quantum and Circularity. But passionate students can also develop their own line of study (in consultation with the mentor). The start of this new program was also a new start for myself, as I started as a new tenure track professor materiomics (specialized in computational materials science) assigned to the chemistry department. As a result, I spend most of my time creating new courses for the new first year of the masters program. This year, the second year is launched for the first time, and also here I have a significant contribution. Together with the courses I’m teaching in the bachelor Chemistry program, my first semester will be packed. I’ll be teaching & coordinating 6 courses (25 ECTS), three of them new,  and contributing to others as well:

  1. Introduction to quantum chemistry (2nd Ba. Chemistry)
  2. Quantum and computational chemistry (3rd Ba. Chemistry, new)
  3. Fundamentals of materials modeling (1st Ma. Materiomics)
  4. Properties of functional materials (1st Ma. Materiomics)
  5. Density functional theory: the workhorse of first principles modelling of solids and molecules (2nd Ma. Materiomics, new)
  6. Machine learning and artificial intelligence in modern materials science (2nd Ma. Materiomics, new)

As you can see, the central theme in these courses will be to introduce students into the realm of computational research, often at the quantum mechanical/chemical level.

On top of that, one of the first generation materiomics students will be performing a master thesis in my group, studying the GeV-defect in diamond. Bachelor students in chemistry and physics may join as well later with computational bachelor projects, but that is beyond my personal event horizon of the end of the first semester.

In the following weeks, you will be able to find a weekly review of my endeavors in this regard, providing some insights into what the students in chemistry and the master materiomics (Physics & Chemistry) are learning at Hasselt University.

Permanent link to this article: https://dannyvanpoucke.be/countdown-to-materiomics-year-2/

Jun 02 2023

E-MRS Spring meeting 2023

  • Filed under blog

  • June 2, 2023

In march 2019, Belgium went into COVID-lock down while I attended the yearly diamond conference (SBDD25). Since then, I have been in a bit of a conference lock down myself as well. By visiting the 2023 spring meeting of E-MRS, this lock down has been lifted for international conferences (outside Belgium). Inside Belgium, there was already the DFT-2022 in Brussels, where I was also part of the National Scientific Committee, and of course SBDD26 & SBDD27, which as a diamond researcher you can not miss.

Coming back to Strassbourg for E-MRS brings back some memories, and generated some nice new ones. This year there was a nice Symposium called “Computations for materials – discovery, design and the role of data“[program] which got my full attention. During the first session on AI-accelerated Materials discovery, I had the pleasure to present some of my own work on the Machine Learning of small data sets (cf. papers on the average model, and UV-curable inks). The symposium was nicely coinciding with much of my interest, and showed two (not unexpected, and maybe symposium biased) trends:

  1.  There is an important evolution toward lab-automation and use of robotics (people don’t want to manually build dozens of battery cells or perform hundreds of repetitive synthesis experiments for materials optimization. This shows the future materials scientist, be it a chemist, physicist or engineer will have to become a robotics and/or programming expert as well. This only strengthens me in my vision for our materiomics [NL] students at UHasselt. These skills will be essential for their future scientific career development.
  2. Machine Learning and Artificial Intelligence will play an important role in future materials design. However, we need a better understanding of what we are doing, and not just use any method and accept it as “excellent” because the RÂČ value is high. For now, we can still get away with the latter, but this will not last much longer. It will become more important to have a simple but interpretable model, rather than a complex (over-fitting) Deep Learning Neural Network without understanding of the underlying physics and chemistry. Also here we will have to put in some effort within the materiomics program.

 

So after an interesting International conference, and making some new contacts…it is time to return home, four more courses need to be prepared from scratch for coming academic year.

Permanent link to this article: https://dannyvanpoucke.be/e-mrs-spring-meeting-2023/

Jan 01 2023

Review of 2022

  • Filed under blog

  • January 1, 2023

Happy New Year

2022 has been a year of many firsts. Most importantly, it is the year I started as a tenure track professor (i.e. assistant professor) starting the QuATOMs group at Hasselt University. In addition, this is the first year the new master materiomics program at UHasselt was provided. In this program, I’m responsible for the theoretical and computational components of materials research, and thus teaching several new classes which are unique in the world. Next year, the second master year will start, with more classes to create.

But before we launch into these new and interesting times, lets look back at 2022 one last time, keeping up with  tradition. What have I done during the last year of academic merit.

1. Publications: +4 (and currently a handful in progress)

2. Cover publication: +1

Cover Polymer International: Machine learning on small data sets, application on UV curable inks.

Cover Polymer International: Machine learning on small data sets, application on UV curable inks.

  • Cover Polymer International
    Danny E.P. Vanpoucke, Marie A.F. Delgove, Jules Stouten, Jurrie Noordijk, Nils De Vos, Kamiel Matthysen, Geert G.P. Deroover, Siamak Mehrkanoon, and Katrien V. Bernaerts,
    Polymer International 71(8), i-i (2022),
    doi: 10.1002/pi.6434 {IF(2021)=3.213}

3. Project proposals accepted: +1

  • Digitization of lignin polyurethane development (DigiLignin), in a consortium with Maastricht University and VITO.

4. Completed refereeing tasks: +12

  • Optical Materials
  • Journal of Applied Physics (2x)
  • Frontiers in Physics
  • Journal of Physics: Condensed Matter (2x)
  • Diamond and Related Materials (6x)

5. Conferences & seminars: +3/+1 (Attended & Organised)

With regard to conferences, 2022 was the year everyone wanted to go back to “normalcy”, though COVID is still very much present.

  • SBDD XXVI, Hasselt University, Belgium, March 9th-11th, 2022 [poster presentation, PhD student]
  • BPS-2022, Tabloo Science expo (SCK-CEN), Belgium, May 18th, 2022 [oral presentation]
  • DFT-2022: 19th International Conference on Density Functional Theory and its Applications, Brussels, Belgium, August 28th-September 2nd, 2022. [member of National Organization Committee; poster]
  • VUB-virtual seminar @ALGC group (F. De Proft), Online, November 29th, 2022 [invited seminar presentation]

6. Current size of HIVE:

  • 62K lines of program (code: 69 %)
  • ~100 files
  • 50 (command line) options

7. Hive-STM program:

And now, upward and onward, a new year, a fresh start.

Permanent link to this article: https://dannyvanpoucke.be/review-of-2022/