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…


CECAM/Psi-k Flagship School on Machine Learning Interatomic Potentials for Young and Early-Career Researchers (ML-IP 2023)

Machine learning interatomic potentials (ML-IPs) have now established themselves as a key technique in atomistic modeling. They allow the simulation of many diverse types of systems, from the molecular to the solid state, at the accuracy of highly sophisticated electronic structure methods but at a greatly reduced cost. While the general methodology of training and validating a machine learning potential has been well established, many codes and integrated software applications exist to perform these tasks. Since many of these come with a high entry barrier, there is still a need to educate young and early-career researchers in these tasks, as well as provide a pathway to enter the field and make valuable contributions for researchers who have promising ideas that could benefit from the application of ML-IPs.

We organized the ML-IP 2023 school at Aalto University, Finland, from 6–10 November 2023 with the broader goal of educating young researchers working on machine learning for materials and molecules on diverse topics, including structural representations, fitting ML models for potentials as well as properties beyond the ground-state potential energy surface, dataset generation and curation, and software frameworks. This was done keeping in mind the applicants’ interest and familiarity with scientific applications, to facilitate the “on-boarding” into the field. This endeavor was supported by funding from both Psi-k and CECAM, aided by additional contributions from Aalto University Department of Chemistry and Materials Science as well as from EPFL’s COSMO laboratory through the ERC-FIAMMA grant.

Applications and participants

Owing to the broad interest in the field, we received an impressive number of applications, over 120 total for in-person participation alone. From this number, 40 were shortlisted to attend the meeting in person; up to 80 more applicants were selected for online participation. In the spirit of supporting early-career researchers, we prioritized those who could benefit the most from attending the workshop in person. To foster diversity amongst participants, both in terms of experience levels in the field and backgrounds, we gave preference to younger researchers (doctoral students and early postdocs) and selected applicants based on motivation and potential to learn from the workshop. While a good proportion of participants were women researchers and those from other traditionally underrepresented groups, we note that we are still far from fair representation of these groups (e.g. gender equality and good representation of non-European researchers), which is an ongoing issue in our research field that we all have a responsibility to address.

We note, especially given the current political climate, that visa issues hindered travel amongst several participants of non-European nationality, in a few cases resulting in the cancellation of their on-site participation, ultimately harming the workshop’s goals of open scientific exchange.

Workshop format

As the workshop was organized in a hybrid format, talks and hands-on tutorials were given by 13 invited speakers in-person at Aalto University, with 3 more speakers joining remotely. Tutorials were held at the end of each workshop day, with sufficient time for both the speaker to present their tutorial and the attendees to work through the tutorials on their own. Despite the preparation work done in advance, technical issues (especially joining and using the supercomputer infrastructure made available to attendees) did pose a barrier for many of the workshop attendees in these sessions.

All of the workshop attendees were provided the opportunity to present and discuss their own work at a poster session. Several presentation slots were also made available for the attendees, and the speakers for these slots were chosen based on the poster abstracts. The poster session was held both in person and online (on Gather Town). This dual format of the poster session provided another opportunity to facilitate the interactions among online and offline participants, although the overall participation in the online poster session was quite low. Nonetheless, enforcing the hybrid format enabled contributions from speakers who were otherwise unable to join the workshop to these sessions. Awards were presented for the three best contributed talks and three in-person poster presentations.

Finally, a Slack workspace served as an additional opportunity for participants and speakers to have discussions, pose questions, and continue to strengthen the community of young and early-career researchers in the field of machine learning potentials. Many of the speakers kindly participated in these interactions, which further catalyzed the learning process of the attendees.

The scientific program was complemented by social events that gave participants a chance for informal networking in a more relaxed setting, which was appreciated by many.

Feedback and future planning

To conclude the workshop, a focus session was held to receive feedback and suggestions for future editions of this workshop. The feedback from the workshop participants, obtained in-person and over Slack during the workshop and in a survey circulated after the workshop, was enthusiastically positive. Participants particularly valued the high proportion of early-career researchers, the ability to actively interact with the speakers, in an atmosphere that encouraged a flat hierarchy and interactions between researchers with different experience levels.

Most attendees considered the scientific level of the talks as appropriate overall, although some expressed the need for more in-depth and introductory lectures at the graduate level as opposed to the working-level knowledge of most practitioners in the field.
The tutorials, however, posed some issues, most of which were technical, starting from hassles with registration and accounts on the cluster to long queuing times on clusters, which significantly impacted the intended interactive nature of these sessions and left the participants with little time to fully engage with the contents of the tutorial and instructions from the speakers.

The online poster session was useful for some people, but the overall participation was quite low. In the future, requiring or strongly encouraging on-site participants to also add their posters online could help with this problem.

Due to the continuing growth of this field, the number of applicants who had to be turned away, and the interest explicitly expressed by attendees, we expect a future edition of this workshop to be well-received. In the discussion session on the “future of ML-IP” held at the end of the workshop, a need was expressed for a written guide to the organization of future events, as well as a need to rethink the online portion of the event, given the significant additional organizational effort needed to run the online part of the conference.

Key future improvements

Based on this participant feedback and our collective experience as organizers, we identified some key areas of improvement for the next editions of the workshop:

  • Increase the geographic diversity of participants (as the current demographic was mostly Europe-based). While the hybrid nature of the event helped expand the reach to other countries, this representation must also be reflected on-site, even while working under the current restrictions.
  • Actively encourage people from under-represented groups (women, people of color, and LGBTQ+ people, for example) to apply and participate, and additionally become involved in the conference organization. Also, begin gathering demographic data to support this goal.
  • Foster collaboration with industry by more proactively reaching out to industrial contacts for scientific contributions and sponsorship. This could also help support travel costs for those traveling from less-resourced countries.

Quantum Monte Carlo HPC Applications in Condensed Matter, Quantum Chemistry and Materials Science 25 January 2024 | 09:30 -12:30 CET

Join us for a deep dive into the cutting edge of quantum materials research and quantum chemistry at the upcoming webinar on “Quantum Monte Carlo HPC Applications in Condensed Matter, Quantum Chemistry, and Materials Science” on January 25, 2024, from 09:30 to 12:30 CET. The webinar is a collaborative effort between the Targeting Real Chemical Accuracy at the EXascale (TREX) project and CECAM (Centre Européen de Calcul Atomique et Moléculaire).

Overview and objectives

The webinar will be exploring the frontiers of quantum materials research and quantum chemistry,  by means of Quantum Monte Carlo (QMC) calculations, owing to their unique suitability in solving complex many-body problems as well as in harnessing the parallelism offered by upcoming exascale supercomputer architectures.

The agenda covers a spectrum of key topics, including magnetism, surface physics, layered materials, energy excitations, and high-pressure hydrogen. Participants will gain a deeper insight into high-performance computing applications via quantum Monte Carlo simulations.

Target Audience

This webinar caters for researchers, students and professionals in the fields of quantum chemistry, condensed matter physics, and materials science.


Theoretical Spectroscopy Lectures :: Cecam School March 2024

dear colleagues and friends,
it is with pleasure that we announce the forthcoming

Theoretical Spectroscopy Lectures

that are going to take place in CECAM, Lausanne
March 11, 2024 – March 15, 2024.

The deadline for registering is 5 February 2024.

The event is going to take place at the CECAM HQ in Lausanne. Please take note that in order to participate to the hands-on sessions, you are required to come with a laptop (better if running under Linux).

Please find here the details of the school

We thank Psi-k and the gdr REST for extra funding.

Looking forward to seeing you in Lausanne.

The organisers,

Francesco Sottile
Gian-Marco Rignanese
Valerio Olevano

New Psi-k Chair

As we move into a new year Psi-k is delighted to announce the election of a new Chair, Professor Arash Mostofi of Imperial College London. Professor Mostofi will follow on from previous Chair, Professor Peter Haynes, who has now come to the end of his term.

Arash Mostofi is Professor of Theory and Simulation of Materials in the Departments of Materials and Physics at Imperial College London. His research is dedicated to the development and application of first-principles modelling tools for the theory and simulation of materials. He is an original author and developer of the Wannier90 and ONETEP codes and his research interests include electronic structure software development, 2D materials, defects and interfaces, and perovskite and layered perovskite oxides.

We would like to take this opportunity to thank Professor Haynes for his leadership of Psi-k over the last three years and look forward to working with him as the Chair of the next Psi-k Conference that will be held in Lausanne, Switzerland in 2025.

Summer School “Towards exascale solutions in Green function methods and advanced DFT” Paphos, Cyprus, October 3-8, 2023

This summer school targeted an audience consisting of PhD students and young postdocs, industry-based researchers as well as researchers from countries without tier 0 supercomputing facilities. There were 45 participants, among which 9 ladies. The school covered a wide range of topics to show the challenges and opportunities of exascale computing in ab initio materials science. Lectures provided in-depth information on the fundamentals of advanced exchange-correlation functionals, many-body perturbation theory based on Green functions, and coupled-cluster method applied to solids. Special focus was on libraries and software applications developed in the NOMAD Center of Excellence, for which training was provided, including on LUMI,, a powerful pre-exascale European Union high-performance computer. Fundamentals and recent developments in the field were presented by recognized experts, and there was plenty of room for open exchange between the young scientists and established international experts. Continue reading Summer School “Towards exascale solutions in Green function methods and advanced DFT” Paphos, Cyprus, October 3-8, 2023

CECAM/Psi-k workshop: Atto2Nano: modeling ultrafast dynamics across time-scales in condensed matter

The CECAM/Psi-k workshop: Atto2Nano: modeling ultrafast dynamics across time-scales in condensed matter took place between September 26th and September 29th, 2023 at the CECAM Headquarter at EPFL, Lausanne, Switzerland. The event attracted 37 participants from 12 countries, featuring invited talks, contributed talks, poster sessions, as well as two round-table discussions.

Overall, this workshop brought together researchers with complementary expertise in the field of experimental and theoretical ultrafast science with the goal of stimulating discussion and exchange on bridging time-scales in both ab-initio and semi-empirical approaches for non-equilibrium phenomena, focusing on time-scales ranging from attoseconds to nanoseconds. While the primary focus of the workshop was on theoretical and numerical modelling of ultrafast dynamics, our event further attracted participation of emerging and leading experimentalists from the area of time-resolved spectroscopy and microscopy.

Continue reading CECAM/Psi-k workshop: Atto2Nano: modeling ultrafast dynamics across time-scales in condensed matter

Report about workshop “Twistronics of 2D materials: from modelling to real systems”


The workshop took place from Sept. 20-22, 2023 at the National Graphene Institute at the University of Manchester. A total of 116 scientists registered for the workshop in addition to the 15 invited speakers and the two workshop organizers (Prof. Vladimir Falko and Prof. Johannes Lischner). Out of the 116 registered attendees, 45 attended the workshop in person while the others attended the live broadcast of the talks which was delivered as a zoom webinar. The workshop featured a mix of invited speakers (15 in total) who delivered 30 minute presentations and contributed speakers (15 in total) who deliver 20 minute presentations. In addition, poster sessions were held during lunch breaks on Sept. 20 and Sept. 22. In addition to the support from Psi-k, the workshop received financial support from the Royce Institute and the CCP9 network.

Continue reading Report about workshop “Twistronics of 2D materials: from modelling to real systems”

WE-Heraeus workshop on First-principles Green function formalisms

First-principles Green function formalisms: algorithms, method developments and applications to spinorbitronics and magneto-superconductivity

4-7 of September 2023, Athens, Greece

The WE-Heraeus workshop entitledFirst-principles Green function formalisms: algorithms, method developments and applications to spinorbitronics and magneto-superconductivity” took place from 4-7 of September in Athens, Greece. After years of only online meetings, the generous funding by the Psi-k charity and the WE-Heraeus Foundation made it possible to bring together the ab-initio Green function community in person. This workshop fostered networking opportunities and important personal exchange among different groups of method developers in the ab-initio Green function community. This was further stimulated by the complementary coffee breaks and lunches that were served in the rooms of the Kostis Palamas building of the National and Kapodistrian University of Athens where the entire workshop took place. Continue reading WE-Heraeus workshop on First-principles Green function formalisms

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