As part of my previous work on the adcc code for computational spectroscopy based on the algebraic-diagrammatic construction (ADC), we also integrated the package with QCEngine. This package aims at integrating different quantum-chemistry codes under a common interface for end users, which is an effort I fully support. Recently the …
read moreA robust and efficient line search for self-consistent field iterations
In an ongoing effort with Antoine Levitt our aim is to develop reliable density-functional theory (DFT) methods for computational materials design. Recently we looked into a strategy to automatically select the damping parameter for the self-consistent field iterations (SCF). Our adaptive damping approach is based on a theoretically sound quadratic …
read moreQ-Chem 5 paper
About two years ago I integrated my open-source ctx library into the Q-Chem quantum-chemistry software suite. Quickly
read morectxbecame part of the core stack for managing computational results inside Q-Chem. In particular inside theccmanandadcmanmodules, which are responsible for most of the coupled-cluster and algebraic-diagrammatic construction methods …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 …
read moreDFTK: 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 …
read moreA 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 …
read moreGator: 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 …
read moreCESMIX 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 …
read moreHigh-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 …
read moreChallenges 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 …
read moreMoansi: 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 …
read moreFaraday 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 …
read moreBlack-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 …
read moreDFTK: 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 …
read moreSCF preconditioning for mixed systems
Fortunately the general lockdown due to the Corona pandemic slowly starts to ease around Paris as well. While basically all seminars are only virtual it is good to see old procedures and habits to slowly return. From my end I gave the first talk after the forced break today in …
read moreRecent developments in adcc
Since the publication of the adcc paper a few months back, there are a few updates to report briefly:
- adcc can now be interactively tried in the browser at try.adc-connect.org using the infrastructure from the binder project.
- Binary installation of adcc is now available via conda for Linux …
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 …
read moreA 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 …
read more1st GDR NBODY meeting in Lille: Applications of DFTK
Earlier this month the first annual meeting of the French working group NBODY (GDR NBODY) took place in Lille. Since the GDR NBODY is an association of interdisciplinary scientists working on N-body problems in chemistry an physics, the about 80 participants came from a broad background ranging from quantum …
read moreTalk in Toulouse: adcc and DFTK
A few weeks ago on 21st and 22nd November of this year Pierre-Francois Loos invited me for two days to the Laboratoire de Chimie et Physique Quantiques of the Université Paul Sabatier Toulouse. On Thursday the 21st I had the chance to present our current status in DFTK and adcc …
read moreadcc: 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 …
read moreJuliaParis: Electronic structure simulations using Julia
Yesterday we had the first instance of the Julia Paris Meetup. As the name suggests a couple of us Julia enthusiasts in the French capital got together for one evening of talks and chatting about everyone's favourite programming language. It was a great occasion to finally meet some people in …
read moreInterdisciplinary 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 …
read moreInterdisciplinary 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 …
read moreModern software-development techniques in electronic structure theory
A few weeks ago, on 23rd May I received an invitation to visit the Laboratoire de Physique des Lasers, Atomes et Molécules at the Université de Lille and present about my recent work. When it came to selecting a topic, me and my host, Andre Gomes, quickly agreed to focus …
read moreCoulomb Sturmian basis functions in electronic structure theory
Earlier this month, on 3rd of May, I was invited for a day to the Laboratoire de Physique et Chimie Théoriques of the Université de Lorraine in Metz. Unlike my earlier stay in Metz stay, during the MES conference, last August, I did not manage to enjoy this beautiful city …
read moreCoulomb 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 …
read morePostDoc 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 …
read moreSelfConsistentField.jl: A julia toolbox for coding self-consistent field algorithms
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 …
read moreQuantum 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 …
read moreSimulating 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 …
read moreFranco-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 …
read moreMES 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 …
read moreEmbedding 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 …
read moreCoulomb 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 …
read moreTowards 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 …
read moreAachen: 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 …
read morePublication 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 …
read moreOberwolfach 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 …
read moreOberwolfach 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 …
read moreLazy 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 …
read moreCoulomb-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 …
read moreIWR School: Mathematical Methods for Quantum Chemistry
From 2nd to 6th October 2017 the IWR hosts the school Mathematical Methods for Quantum Chemistry, which aims at shining some light into the simulation of quantum chemical problems and their mathematical properties. I am very happy to be part of the organising committee for this school, especially since I …
read moreLazy matrices in quantum chemistry
On my way back from Copenhagen last Thursday I stopped in Kiel to visit Henrik Larsson and some other people from last year's Deutsche Schülerakademie in Grovesmühle.
Henrik is doing his PhD at the group of Prof. Bernd Hartke and so I took the opportunity and gave a short talk …
read moreHPC day at Niels Bohr Institute
look4bas: Small script to search for Gaussian basis sets
In the past couple of days I hacked together a small Python script, which searches through the EMSL basis set exchange library of Gaussian basis sets via the commandline.
Unlike the webinterface it allows to use
read moregrep-like regular expressions for matching the names and descriptions of the basis sets …The design of molsturm
Yesterday I was invited to the give a talk at the group seminar of Prof. Thomas Kühne at the University of Paderborn. I was really happy about this invitation, since this gave me a great opportunity to talk about the recent direction my PhD has taken.
Motivated from the problems …
read more51th Symposium on Theoretical Chemistry (Potsdam)
[c¼h] Einführung in die Elektronenstrukturtheorie
The week before my bash scripting course I gave another short talk for the weekly meeting of the Heidelberg Chaostreff NoName e.V. Unlike last time the talk was not concerned with a traditional "Hacker" topic, but much rather I tried to give a brief introduction into my own research …
read moreA short return to Cambridge
About two weeks ago, on Friday the 13th of March, I was invited back to the Chemistry Department at the University of Cambridge. As part of their Theoretical Chemistry Informal Seminar talk series I was asked to give a short talk (Abstract) about my current research. Needless to say that …
read more50th Symposium on Theoretical Chemistry (Vienna)
Last month, from 14th to the 18th of September, I attended my first conference. Together with many members of my group I was at the 50th Symposium on Theoretical Chemistry in Vienna. It was a great opportunity to present my work, get feedback on some ideas and get to know …
read morePhD 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 …
read moreMaster Thesis: Tunnelling in water clusters
In my first post I'll briefly talk about my first proper piece of research, my Master thesis. As part of my last year of Cambridge I spent 6 months doing a project in the theoretical chemistry group of Prof. Dr. Stuart Althorpe. Although I've done a few smaller research projects …
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