1. JuliaCon BoF discussion session: Building a Chemistry and Materials Science Ecosystem

    The second event I co-organised at this year's JuliaCon (see this article for the other) was a Birds of Feather (BoF) discussion session titled Building a Chemistry and Materials Science Ecosystem in Julia. In this session Rachel Kurchin and I wanted to gather the various stakeholders working on Julia codes …

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  2. JuliaCon DFTK workshop: A mathematical look at electronic structure theory

    From 13th July till 30th July this year's JuliaCon finally took place virtually. The first week (13th till 27th) hosted a number of three-hour live-streamed sessions of workshops, while the "regular" conference with a number of prerecorded talks started on 28th.

    After my introductory talk to electronic structure theory and …

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  3. Virtual materials design 2021: Black-box density-functional theory methods

    On 20th and 21st July 2021 the Virtual Materials Design 2021 CECAM workshop took place virtually. I was excited about this workshop and the opportunity to get in touch with researchers working on high-throughput computational materials design. While I am not actively working in this field the special requirements of …

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  4. SSD Seminar: Accelerating the discovery of tomorrow's materials by robust and error-controlled simulations

    A couple of days ago, on 12th July, I was invited to present my research in the SSD Seminar Series of RWTH Aachen. Being part of the research training group on modern inverse problems as well as the School for Simulation and Data Science (SSD) the SSD seminars are interdisciplinary …

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  5. Errors and uncertainty quantification in density-functional theory

    On 8th June I was invited to the seminar of the Uncertainty Quantification (UQ) group of Prof. Youssef Marzouk at MIT. Youssef and I planned to have this seminar since my involvement with MIT's CESMIX project last February (see also this blog article), but it took use quite some time …

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  6. Talk at MATH4UQ seminar series at RWTH

    On 1st June I was invited to the MATH4UQ seminar series of the Mathematics of Uncertainty Quantification chair of Prof. Raul Tempone at RWTH Aachen University.

    Over the past months I got more and more interested in mathematical methods for uncertainty quantification (UQ) as an opportunity to estimate and understand …

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  7. SIAM LA: Robust and efficient accelerated methods for density-functional theory

    Just one day after my talk at the SIAM Materials Science conference (blog article) I gave another talk at a SIAM meeting, this time at SIAM Linear Algebra. I was very much looking forward to participate in SIAM LA, firstly because it was the first time I attended this conference …

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  8. SIAM MS: Using the density-functional toolkit to design black-box DFT methods

    After being moved by one year due to the pandemic, the last two weeks (from 17th to 28th May) the SIAM materials science conference finally took place in virtual form. Unfortunately this meant that the conference was scheduled in parallel to the SIAM Linear Algebra virtual conference, where I also …

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  9. DFTK: A Julian approach for simulating electrons in solids

    Following my talk at Juliacon about our DFTK code last year (slides, recording, blog article), we have now published an extended abstract in the JuliaCon proceedings, which you can find below. The JuliaCon proceedings use the same open journals software stack to manage their publication infrastructure as the Journal of …

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  10. Thoughts on initial guess methods for DFT

    On Thursday I gave a brief talk in our weekly ACED differentiate group meeting about initial guess methods for starting self-consistent field calculations in methods such as density-functional theory. For preparing the talk I did a little digging into both the standard approaches used by many molecular and solid-state codes …

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  11. A novel black-box preconditioning strategy for high-throughput density-functional theory

    A couple of weeks ago, from 15th to 19th March, I participated in the virtual annual meeting of the German Association of Applied Mathematics and Mechanics (GAMM). For me this meeting was the first time I presented my work to an audience of applied mathematicians with a broad background and …

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  12. PostDoc position at Appl. & Comput. Mathematics lab, RWTH Aachen University

    This week I started my new position as a postdocotoral researcher at the Applied and Computational Mathematics (ACoM) research lab at RWTH Aachen University. The lab consists of two interdisciplinary research groups, namely the group of Prof. Dr. Manuel Torrilhon, who works on the mathematical modelling and simulation of technical …

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  13. Gator: a Python-driven program for spectroscopy simulations

    A bit over a year ago we published our adcc code. In this work the aim was to develop a toolkit for computational spectroscopy methods focused on rapid development and interactive hands-on usage (see the blog article for details). Our target back then was to simplify method development involving the …

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  14. CESMIX TST meeting: DFTK.jl: A multidisciplinary Julia code for density-functional theory development

    These past two days I have participated in the Tri-Lab Support Team (TST) meeting of the CESMIX, the newly founded Center for the Exascale Simulation of Material Interfaces in Extreme Environments at the Massachusetts Institute of Technology. Within the next few years the idea of the CESMIX is to develop …

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  15. High-throughput density-functional theory calculations: An interdisciplinary challenge

    Last Thursday I was invited to give a virtual talk at the Scientific Computing Seminar of working group of Prof. Nicolas Gauger at TU Kaiserslautern. Since the research in Prof. Gauger's group mostly concerns topics which are not directly related to electronic structure theory and density-functional theory (DFT), I chose …

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  16. Challenges and prospects of a posteriori error estimation in density-functional theory

    Last week Wednesday I was invited to give a talk at the group seminar of the AG Christoph Jacob at TU Braunschweig, Germany. Christoph was especially interested in our recent publication on a posteriori error estimation in Kohn-Sham problems and so I decided to use the opportunity to give a …

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  17. Moansi: Inhomogeneous preconditioning for density-functional theory

    Last week (24th and 25th September) I attended the 4th annual meeting of the Moansi (Modelling, analysis and simulation of Molecular Systems) work group of the GAMM. I already attended the Moansi meeting last year, where I very much enjoyed both the broad range of talks at the interdisciplinary border …

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  18. Faraday Discussions: New horizons in density functional theory

    Following the submission of our paper on a posteriori error estimation in the Kohn-Sham equations a few months ago I was recently invited to present our work at the Faraday Discussions on New horizons in density functional theory. Being amongst speakers such as Kieron Burke, Andreas Savin or Weitao Yang …

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  19. Black-box inhomogeneous preconditioning for self-consistent field iterations in density-functional theory

    For the past half a year or so Antoine Levitt and myself have been looking at a particular tricky busyness for solid-state density-functional theory (DFT) calculations, namely how to design efficient self-consistent field (SCF) schemes for large inhomogeneous systems. I have already previously reported on this matter in a short …

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  20. DFTK: A Julian approach for simulating electrons in solids

    Since last Friday I have been attending JuliaCon, the annual conference for the Julia language. Naturally given the current situation the event did not take place "on location", but was instead converted into a virtual event. Albeit the different feel compared to a real-life conference the organisers did a very …

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  21. Quantifying the error of the core-valence separation approximation

    After only a few months of publishing our adcc paper, which introduces the novel algebraic-diagrammatic construction (ADC) code adcc, the package has already found mention in a number of related articles. One example is a manuscript on updates in the Psi4 quantum chemistry package, which features adcc as one of …

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  22. A posteriori error estimation for the non-self-consistent Kohn-Sham equations

    After about a year of work on the density-functional toolkit (DFTK) we finally started using the code for some new science. Given the mathematics background of the CERMICS the first two DFTK-related articles were not so much about large-scale applications, but rather deal some fundamental questions of Kohn-Sham density-functional theory …

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  23. adcc: A versatile toolkit for rapid development of algebraic-diagrammatic construction methods

    Over the part year or so a side project I have been working off and on has been the adcc code. This python module allows to perform excited states calculation for simulating molecular spectra based on algebraic-diagrammatic construction (ADC) methods. The speciality of the adcc code is that (a) multiple …

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  24. Interdisciplinary software for electronic structure theory: adcc and DFTK

    Last week, from Wednesday to Friday, I paid the Technical University of Munich (TUM) a short visit for two great opportunities to present my work: Once in the theoretical chemistry group of Professor Wolfgang Domcke and once at the annual meeting of the modeling, analysis and simulation of molecular systems …

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  25. Interdisciplinary software development in electronic structure theory (MQM Poster)

    At the beginning of the month, from 30th June till 5th July, I attended the 9th Molecular Quantum Mechanics Conference in my old home Heidelberg. This occasion was a great opportunity to catch up with friends and colleges both in science and from my old circle in Heidelberg as well …

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  26. Coulomb Sturmian basis functions in electronic structure theory

    After my first Coulomb Sturmian-related talk at the LCT last November, I was approached by Julien Toulouse and asked whether I could give another talk providing a little more insight into Coulomb Sturmians and their potential.

    A few weeks ago, on 29th March, it was thus about time for a …

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  27. PostDoc position at CERMICS / Sorbonne Université

    Last week I started my new position as a postdoctoral fellow at the MATHERIALS team of the Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS) laboratory and Inria Paris with an additional affiliation to the Institut des Sciences du Calcul et des Données at Sorbonne Université. As …

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  28. SelfConsistentField.jl: A julia toolbox for coding self-consistent field algorithms

    Over the past half a year I became interested in the julia programming language. It is a rather recent language (version 1.0.0 just released last August), which promises to provide a modern approach to scientific computing. From my experience so far, I like julia a lot. All aspects …

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  29. Design of the molsturm quantum-chemistry framework

    A few weeks ago, on 23rd November, I was invited to speak at the mathematics and chemistry seminar (GdT mathématiques et chimie) at Sorbonne Université in Paris. This seminar is a joint meeting of theoretical chemists and mathematicians from the LJLL (Laboratoire Jacques-Louis Lions) and the LCT (Laboratoire de Chimie …

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  30. Quantum chemistry with Coulomb Sturmians: Construction and convergence of Coulomb Sturmian basis sets at Hartree-Fock level

    This week we submitted a paper related to our ongoing work regarding the use of Coulomb Sturmian basis functions in electronic structure theory. Given the recent progress, which has been made with regards to the evaluation of molecular integrals based on these exponential-type functions, molecular calculations based on Coulomb Sturmians …

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  31. Simulating chemistry: Enabling novel approaches for modelling the electronic structure of molecules

    Last week Wednesday I was invited to present my research in front of a bunch of young researchers from the Heidelberg Laureate Forum visiting our institute. Whilst I would have loved to attend the full week of the forum, I am happy that in this way I was able to …

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  32. Franco-German Workshop 2018: Open problems related to the algebraic-diagrammatic construction scheme

    In some of my recent projects, e.g. the PE-ADC paper, I got a little more into method development surrounding the algebraic-diagrammatic construction scheme (ADC). Even though quite a few people from the Dreuw group in Heidelberg are involved with ADC development and we have regular talks on ADC, I …

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  33. MES 2018 in Metz: molsturm Towards quantum-chemical method development for arbitrary basis functions

    Currently I am attending the Molecular Electronic Structure 2018 conference in Metz, an electronic-structure theory conference intended for researchers working on novel methodologies, such as explicit correlation, density matrix theory, stochastic approaches or on discretisation techniques going beyond Gaussian-type orbitals.

    Especially the latter aspect fits well to the kind of …

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  34. Embedding Combined with the Algebraic Diagrammatic Construction: Tackling Excited States in Biomolecular Systems

    Yesterday the journal of chemical theory and computation accepted our manuscript titled Polarizable Embedding Combined with the Algebraic Diagrammatic Construction: Tackling Excited States in Biomolecular Systems. In this work we describe the combination of the polarisable embedding (PE) scheme for including environmental effects with the algebraic-diagrammatic construction (ADC) approach.

    The …

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  35. Coulomb Sturmians in electronic structure theory (Poster at 16th ICQC)

    Last week from 18th till 23rd June I attended the 16th International Congress of Quantum Chemistry (ICQC) in Menton, France. Apart from the absolutely stunning scenery at the French Riviera as well as the historic conference building, the conference was a great opportunity to meet up and discuss with people …

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  36. Towards quantum-chemical method development for arbitrary basis functions

    Last week we submitted the molsturm design paper titled Towards quantum-chemical method development for arbitrary basis functions. This manuscript is a condensed summary of the arguments about design and implementation of a basis-function independent self-consistent field scheme (SCF) already presented in my PhD thesis.

    Our approach to a basis-function-independent electronic …

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  37. Aachen: Beyond Gaussian-type orbitals

    From Monday till Wednesday this week I was invited to the computational mathematics research group of Prof. Dr. Benjamin Stamm at the RWTH Aachen University. In retrospect I am very thankful for the invitation, since the three days turned out to be filled with fruitful discussions, scientific exchange and brainstorming …

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  38. Publication of my PhD thesis

    Finally, after quite some years of work I have successfully defended my PhD thesis with the title Development of a modular quantum-chemistry framework for the investigation of novel basis functions on 22nd May. An electronic version of the text has now been published online.

    To make the topic of my …

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  39. Oberwolfach reports: Molsturm modular electronic structure theory framework

    As announced in my previous post about the Oberwolfach workshop on Mathematical Methods in Quantum Chemistry, the proceedings of each Oberwolfach workshop are published in the form of an article in the Oberwolfach reports. For this purpose each speaker is asked for an extended abstract summarising the content of his …

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  40. Oberwolfach workshop: Mathematical Methods in Quantum Chemistry

    Last week I was invited to the Mathematical Research Institute Oberwolfach (Mathematisches Forschungsinstitut Oberwolfach) for a workshop about Mathematical Methods in Quantum Chemistry. I am really grateful to the organisers Eric Cancès, Gero Friesecke, Trygve Helgaker and Lin Lin for asking me to join this meeting as it turned out …

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  41. Lazy matrices talk from the IWR school 2017

    As mentioned in a previous post on this matter last month, from 2nd to 6th October, the IWR hosted the school Mathematical Methods for Quantum Chemistry, which I co-organised together with my supervisors Andreas Dreuw and Guido Kanschat as well as the head of my graduate school Michael Winckler.

    From …

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  42. Coulomb-Sturmians and molsturm

    Yesterday I gave a talk at our annual group retreat at the Darmstädter Haus in Hirschegg, Kleinwalsertal. For this talk I expanded the slides from my lazy matrix talk in Kiel, incorporating a few of the more recent Coulomb-Sturmian results I obtained.

    Most importantly I added a few slides to …

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  43. PhD Project: Finite Element Methods in Quantum Chemistry

    In January I officially started my PhD in the Theoretical Chemistry group of Prof. Dr. Andreas Dreuw at the Interdisziplinäres Zentrum für wissenschaftliches Rechnen of the Ruprecht-Karls-Universität Heidelberg. The principle aim of the project is to replace the common formalism of using atom-centered basis functions (e.g. Gaussian atomic orbitals …

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