The Psi-k Community

MISSION: Psi-k is a Europe-based, worldwide network of researchers working on the advancement of first-principles computational materials science. Its mission is to develop fundamental theory, algorithms, and computer codes in order to understand, predict, and design materials properties and functions. Theoretical condensed matter physics, quantum chemistry, thermodynamics, and statistical mechanics form its scientific core. Applications encompass inorganic, organic and bio-materials, and cover a whole range of diverse scientific, engineering, and industrial endeavours. Key activities of Psi-k are the organization of conferences, workshops, tutorials and training schools as well as the dissemination of scientific thinking in society.

Psi-k is a bottom-up researchers’ network, established in 1994, to build strength and cooperation in the field of computational electronic structure. Psi-k activities are coordinated by a Board of Trustees, a Scientific Advisory Committee, and 16 Working Groups. These activities encompass the organization or co-sponsoring of ~30 workshops, conferences, schools or tutorials every year, an annual research conference jointly with CECAM, and a major conference covering the entire field every 5 years.

In addition, Psi-k produces a regular newsletter with extensive scientific highlights, and allows researchers to advertise job openings, events, and other topics of mutual interest through its 5000+ members mailing list.

This new website — introduced in  2015 to replace a venerable old site that provided sterling service over many years — offers a much more flexible modern design and functionality and it is to be hoped that it will provide even more stimulus for collaboration and cooperation amongst its members. Instructions regarding how to use it are here.

Psi-k is a registered charity and can only continue to operate thanks to the contributions from our member organisations and institutions. If you would like to make a donation to Psi-k please contact us to request an invoice or make a donation directly through our PayPal account…


10th ABINIT International Developer Workshop – Part 2

10th ABINIT International Developer Workshop – Part 2
May 16-19, 2022 Guidel-Plages, France

Event website
The complete list of participants can be found here.

General presentation

The ABINIT developer workshops form a series of events, crucial for the community of ABINIT developers, organized every two years. A unique occasion for most developers to acquire or maintain a global view of the project and stay up to date with the latest capabilities, planned developments, and overall strategy. The developer workshop is always an opportunity to invite external researchers, from other codes and communities, to exchange best practices and expertise…

This workshop was the second part of the 10th ABINIT developer workshop. It was held from 16th to 19th May 2022 in Guidel-Plages (Brittany, France).

Because of the COVID19 pandemic situation, in June 2021, the meeting occurred in a fully remote version, with only remote presentations and some group discussions. We missed several important parts of the workshop : small group discussions, thematic discussions, informal discussions, hackathons, etc. Many of the participants emphasized the need to meet again in person when the health situation permits it.

In May 2022 we organized the second part of the workshop, with a smaller number of participants, mostly based on the missing ingredients above, plus a few invited presentations. It was a complementary and entirely live/offline event, consisting of discussions, round tables and hackathons. The physical presence of developers was a requirement to have efficient round tables and informal discussions.

The workshop was mainly dedicated to implementations and decision making by the developers:

Every morning we had a session of hackathons. Divided into small groups, we worked on the ABINIT package : coding, improving the documentation, creating tutorials, interfacing the code with other software, etc. Each developer chose projects and hackathons according to his/her specific expertise in the project.

During two afternoons, we met collectively to discuss and consider the future of the code: future scientific themes, dissemination and the visibility, user experience improvement.

A third afternoon was dedicated to invited speakers’ presentations. The speakers were chosen because of their involvement in projects external/complementary to ABINIT. Continue reading 10th ABINIT International Developer Workshop – Part 2

CECAM / Psi-k workshop “Error control in first-principles modelling”

From 20th until 24th June 2022 we organised a workshop on the theme of “Error control in first-principles modelling” at the CECAM Headquarters in Lausanne (workshop website). For one week the workshop unified like-minded researchers from a range of communities, including quantum chemistry, materials sciences, scientific computing and mathematics to jointly discuss the determination of errors in atomistic modelling. The main goal was to obtain a cross-community overview of ongoing work and to establish new links between the disciplines.

Amongst others we discussed topics such as: the determination of errors in observables, which are the result of long molecular dynamics simulations, the reliability and efficiency of numerical procedures and how to go beyond benchmarking or convergence studies via a rigorous mathematical understanding of errors. We further explored interactions with the field of uncertainty quantification to link numerical and modeling errors in electronic structure calculations or to understand error propagation in interatomic potentials via statistical inference.

Continue reading CECAM / Psi-k workshop “Error control in first-principles modelling”

Report for the workshop “Astrochemistry meets Surface Science: Theoretical Frontiers”

Scientific Report for the workshop “Astrochemistry meets Surface Science: Theoretical Frontiers”

April 5th – 8th 2022

Aarhus Institute of Advanced Studies, Aarhus University, Denmark


The goal of the workshop was to bring closer together the research communities of theoretical Astrochemistry and theoretical (under Earth conditions) Surface Science. These two fields often address very similar questions, while using the exact same techniques and methodologies (e.g. electronic structure methods such as density functional theory, molecular dynamics or kinetic Monte Carlo simulations). And yet, despite these similarities, a noticeable communication gap exists between the two communities. Our multidisciplinary workshop aimed to bridge this gap and help establish new networking and collaboration ties between these fields.

The workshop covered a broad range of topics ranging from surface reaction networks and kinetic models to the characterization of interstellar ices and questions of energy dissipation and heat transport. In parallel to the underlying scientific questions, special focus was placed on theoretical and methodological aspects, as well as computational and numerical tools that are used in either one or both of the fields of astrochemistry and Earth-related surface science.

Continue reading Report for the workshop “Astrochemistry meets Surface Science: Theoretical Frontiers”

Scientific Report on the Wannier 2022 Workshop

ICTP, Trieste (Italy), 16-27 May 2022

The last two decades have witnessed a tremendous growth in the use of Wannier functions (WFs) for first-principles electronic structure calculations. Beyond providing fundamental insights on several aspects of the electronic structure, from chemical bonding to electrical polarisation, topological invariants, Berry curvature and more, WFs have found applications in a plethora of different domains. 

The software package WANNIER90 has become a reference for calculating maximally-localised Wannier functions (MLWFs) [1,2] and related properties [2,3,4]. As Wannier functions are independent from the basis sets used to represent the electronic structure in the underlying first-principles calculations, WANNIER90 can be interfaced to virtually any electronic-structure code. Indeed, most of the major electronic-structure packages have already an interface to WANNIER90, including Quantum ESPRESSO, ABINIT, VASP, Siesta, Wien2k, Fleur and Octopus. 

The availability of a robust MLWF code that is connected to several ab-initio engines has acted as a fertiliser for the birth of independent computational efforts aimed at calculating complex materials properties by leveraging WFs. Several independent packages exploiting MLWFs and WANNIER90 exist nowadays, targeting a number of properties, from electron-phonon coupling [5] (EPW) to topological invariants [6] (Z2Pack), surface spectral densities [7] (WannierTools), Berry-phase related properties [8] (Wannier Berri), tight-binding models (PythTB, TBModels), high-throughput calculations [9] (AiiDA-Wannier90), dynamical mean field theory (TRIQS), just to mention a few.

Wannier 2022 has been an event that put together the community behind these symbiotic packages that form a research and software ecosystem built upon the concept of MLWFs. The workshop has served the two-fold objective of teaching several techniques enabled by Wannier functions to young researchers and fostering an integration between all the packages composing the Wannier ecosystem, contrasting fragmentation and duplication of efforts.

This workshop has been generously funded by ICTP, Psi-k, MaX, NCCR MARVEL and CECAM. The computational infrastructure to run the hands-on tutorials has been provided by ICTP through their ICTP Cloud.   

The workshop was run by 6 directors:

  • Antimo Marrazzo, University of Trieste
  • Roxana Margine, Binghamton University
  • Sinisa Coh, University of California Riverside
  • Stepan Tsirkin, University of Zurich
  • Giovanni Pizzi, EPFL
  • Nicola Seriani, ICTP (local organiser)

The event comprised two parts, a summer school (first week) and a developers meeting (second week). 

Continue reading Scientific Report on the Wannier 2022 Workshop

TREX School on QMC with TurboRVB – 04-08 July, Trieste, Italy

We are inviting young students/researchers to the 2nd edition of TREX school on QMC with TurboRVB, organised Scuola Internazionale Superiore di Studi Avanzati (SISSA) and TREX project.

The School will be held from 04-08 July 2022 in Trieste, Italy at Scuola Internazionale Superiore di Studi Avanzati (SISSA) where you will get the chance to attend keynotes presentations, lectures, and hands-on tutorials and applications coming from our HPC experts within the TREX project.

Why should you join the School?

  • The TREX project is offering participants free lodging, coffee breaks, lunch breaks and a social dinner during the School. This will be the perfect occasion to meet your peers and colleagues in person, share experiences and learn more about QMC methods.
  • Participants are invited to submit their poster contributions and present results and ongoing activities at the TREX School. The best poster winners will get the opportunity to be financed as visiting students for one week: one winner will be visiting the SISSA in Trieste (IT) and another winner the CNRS in Paris (FR), with food and accommodation provided by the TREX project.  Please fill out the online form to submit a poster.  The deadline for poster submission is 26 June 2022 at 17:00 CEST.
  • Get the chance to explore beautiful Trieste, top-ranked in Italy for its quality of life, and to discover this town renowned for its scientific institutions. TREX project is not covering participant’s travel costs.

Important Dates

  • Registration is open until 24 June 2022, 17:00 CEST
  • Selected participants will be announced immediately right after the completion of each registration
  • Submission for the Call for Poster is until 26 June 2022, 17:00 CEST


CECAM Psi-k Research Conference 2023

Interested in promoting discussion and fostering collaborations in research areas of broad mutual interest for CECAM and Psi-k?

Submit your expression of interest to organize a CECAM Psi-k Research Conference in 2023 by filling the simple form at:

Deadline for submission of the expression of interest: 4 September 2022

Diversity (specific expertise in simulation and modelling, geographical, gender, career stage…) and interdisciplinarity among organisers and participants are key evaluation criteria.

The CECAM Psi-k Research Conference is a forum to explore and foster progress in exciting new topics and open questions of interest to different communities in simulation and modeling, rather than another opportunity to showcase consolidated research. The proposed duration and format of the event should reflect this spirit, with ample time set aside for common discussions and informal exchanges.

Details of previous CECAM Psi-k Research Conferences can be found online.

If selected for further evaluation, you will be invited to submit a full proposal – format similar to previous years – at the end of September 2022, with a deadline for submission on 31 October 2022.

Last chance to register for the QMC Hands-on summer Wokshop – 20-23.06.2022

This is the final call to register to the QMC Hands-on Summer Workshop, organised by TREX project, Slovak Academy of Sciences (SAS), Institute of Physics SAS (IPSAS) and National Competence Centre for High-Performance Computing (NCHPC).


Important Dates:
  • Registration is open until 26 May 2022, 17:00 CEST
  • Selected participants will be announced on 30 May 2022.
  • Submission for the Call for Poster is open until 19 June 2022, 17:00 CEST

If you have not made up your mind yet about attending the QMC Hands-on Summer Workshop, take a look at the sessions’ descriptions and call for posters.

Selected students attending physically the event will take part in the TREX poster competition.
The winner will be offered the possibility to become a visiting student for one week at the  Institute of Physics SAS in Slovakia with accommodation covered by the TREX project.

Psi-k Funding Call 2023-24 – NOW OPEN!!!

Psi-k  is a worldwide network of researchers working on the advancement of  first-principles computational materials science. Its mission is to  develop fundamental theory, algorithms, and computer codes in order to  understand, predict, and design materials properties and functions. Key  activities of Psi-k are the organization of conferences, workshops,  tutorials and training schools as well as the dissemination of  scientific thinking in society [Excerpt from the mission statement at ].

Psi-k typically funds schools (1-2 weeks), workshops (2-3 days), international conferences (2-5 days), and codes/methods tutorials (3 days-1 week), with a focus on electronic-structure methods,  developments, and applications. Funding is of the order of  4,000/8,000/12,000 €, depending on size and duration (as a guideline, 30  €/expected participant/day); Psi-k funds around 25-35 activities for every call (see here  for the 2022-23 activities).

For this coming round, we are particularly keen to support activities that benefit PhD students and early career researchers, who have missed out on in-person events during the pandemic – schools and tutorials in particular. We also continue to encourage the ingenious development of remote delivery methods where appropriate, to widen the benefit of our activities to groups where the cost of in-person attendance may be a barrier.

We  have a two-step application process to simplify and streamline  applications, elicit more original proposals, improve planning, and avoid duplication of efforts. The present call for outline proposals is for events that will take place between 1 April 2023 and 31 March 2024.

Outline proposals should be submitted online  by Monday 18 July 2022 (midnight UK time), describing the planned event (download a draft of the form to see a preview of the questions that you will be asked here). Psi-k Working Groups ( ) and Trustees ( will either approve this outline proposal for full submission, reject it,  or suggest a merger between different activities – you are very welcome  to contact the relevant Working Group leaders or members beforehand.

Feedback will be provided the week of Monday 19 September 2022.  Outline proposals that have been approved or mergers that have been successfully negotiated will then be invited to submit a full proposal by Monday 17 October 2022. These proposals will then be  evaluated and approved – with full or partial funding – or declined at  the meeting of the Trustees, Scientific Advisory Committee ( and Working Group leaders on Friday 25 November 2022.

The evaluation of the outline proposals and full proposals will be based on

  • the relevance to the Psi-k mission statement;
  • the scientific quality of the proposal;
  • the intellectual inclusivity, geographical spread and diversity of the proposed participants, including efforts to widen participation beyond established groups;
  • the scientific merit, geographical spread and diversity of the organizers; and
  • the appropriateness of budget


  • in case of events that can interest different Working Groups please name the primary Working Group and then any related groups
  • if the event does not relate to any current Working Group, applicants should contact in advance Psi-k at [email protected].



Report on the Theoretical Spectroscopy Lectures

Scientific Report for the
Theoretical Spectroscopy Lectures
March 21-25, 2022
CECAM-HQ-EPFL, Lausanne, Switzerland

The aim of the school was to give a deep introduction to the theoretical and practical aspects of the electronic excitations which are probed by experimental techniques such as optical absorption, EELS, and photoemission (direct or inverse). From the theory point of view, excitations and excited state properties are out of the reach of density-functional theory (DFT), which is a ground-state theory. In the last thirty years, other ab-initio theories and frameworks, which are able to describe electronic excitations and spectroscopy, have become more and more used: time-dependent density-functional theory (TDDFT) and many-body perturbation theory (MBPT) or Green’s function theory (GW approximation and Bethe-Salpeter equation BSE). In fact, computational solutions and codes have been developed in order to implement these theories and to provide tools to calculate excited state properties. The present school focused on these points, covering theoretical, practical, and also numerical aspects of TDDFT and MBPT, non-linear response, and real-time spectroscopies. For the first time, this year we also covered theoretical aspects of magnetic excitations. Finally, a large part of the school was devoted to the codes implementing such theories (ABINIT, 2Light, DP, EXC). Continue reading Report on the Theoretical Spectroscopy Lectures

Ab initio (from electronic structure) calculation of complex processes in materials