The Psi-k Community

Psi-k is a wide network of European researchers — working closely with many friends and colleagues around the world – that is intended to help build cooperation in the field of computational electronic structure calculations, in particular for crystalline quantum systems whose wave function Ψ has an associated wave vector k defining its periodicity, hence the name.  It is co-ordinated by a series of working groups from around Europe. It produces a monthly newsletter, organizes a major conference every five years, and allows researchers to email each other regarding job openings, events, and other topics of mutual interest. The network is also able to provide some degree of financial support for small workshops and schools, and for collaborative research visits.

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.

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.

Scientific Report on the workshop: “MARVEL/MaX/Psi-k Tutorial on high-throughput computations: general methods and applications using AiiDA”

EPFL, Lausanne, Switzerland, 22-24 June 2016

Group picture from the AiiDA tutorial, EPFL June 2016

High-throughput computing (HTC) is emerging as an effective methodology in computational materials science for the discovery of novel materials. Its adoption is spreading rapidly at the point that HTC is becoming an essential tool for computational materials scientists.

The aim of the tutorial was to introduce young researchers to HTC, with hands-on tutorials based on the open-source high-throughput platform AiiDA (, complemented by three invited highlight talks to underscore the diverse application fields of HTC.

We report here a summary of what has happened.

Continue reading Scientific Report on the workshop: “MARVEL/MaX/Psi-k Tutorial on high-throughput computations: general methods and applications using AiiDA”

Ove Jepsen

We are sad to report the passing of Ove Jepsen, who died suddently on January 4th at age 73.

Ove was was an internationally recognized pioneer of electronic-structure calculations. From 1979 until beyond his retirement in 2011 he worked at the Max-Planck Institute for Solid-State Research in Stuttgart where he contributed significantly to the friendly, international atmosphere, had many collaborations across departments, and was highly respected.

The full obituary is available here.

Scientific Report regarding the CECAM Workshop: “Computational insight into photo-induced processes at interfaces”


Thomas Frauenheim (University of Bremen, Germany)

Oleg Prezhdo (University of Southern California, L. A., US)

Sheng Meng (Institute of Physics, CAS Beijing, China)

Johannes Lischner (Imperial College London, UK)

Location:       University of Bremen, Germany,

10th until 14th of October 2016

1. Summary

There is enormous interest in understanding and controlling photo-induced charge transfer and chemical reactions for energy storage. These can be due either to water splitting and carbon dioxide reduction or by electron-hole pair separation at hybrid chromophore- or hybrid polymer-solid interfaces in photovoltaic devices, stimulating an increasing number of experimental and theoretical studies. Computational atomistic studies of experimental realistic setups require models that include an inorganic semiconductor nanostructure, acting as a catalyst and organic molecules in solvents. In photovoltaic applications, e.g. one has to consider multi-component systems, involving several chromophores tuned to absorb different wavelengths of light, an acceptor that removes an electron from the chromophores and creates separated electron-hole pairs, as well as electron and hole conducting media. Such models already may involve hundreds to thousands of atoms, extending far beyond the limits of any ab initio calculations. Furthermore, the non-equilibrium processes involved in the photo-induced charge separation and transport require explicit time domain modelling. Relevant processes occur on ultrafast time-scales and in most cases cannot be described by rate expressions. Charge separation, Auger-type energy exchange between electrons and holes, generation of additional charges by Auger mechanisms, energy losses to heat due to charge-phonon interactions, charge and energy transfer, and electron-hole recombination occur in parallel and competition requiring significant efforts in method development and clarification of multiple conceptual problems.
Continue reading Scientific Report regarding the CECAM Workshop: “Computational insight into photo-induced processes at interfaces”

7th School & Workshop on Time Dependent Density Functional Theory: Prospects and Applications

The Benasque Center for Science

Alberto Castro
Neepa Maitra
Fernando Nogueira
Angel Rubio
E. K. U. Gross

Time-dependent density-functional theory (TDDFT) is but one of the numerous methods used to model the electronic structure in atoms, molecules, and extended systems. Its use is growing fast, as its reliability for many purposes has been sanctioned by many successful applications over the years. The calculation of excitation energies of many varieties of molecules, and the optical absorption spectrum of many solids can be cited as examples. However, in other circumstances TDDFT has to be substituted by more accurate, yet more expensive techniques: advanced correlated post-Hartree Fock techniques, or many-body perturbation theory techniques such as any of the approximations to the solution of Hedin’s equations. Yet TDDFT, as ground-state DFT, could in principle be exact, providing inexpensive solutions to all electronic structure problemas. How can one approach this goal was the starting question for this workshop – and, in fact, it has been the motivation behind the full series of the Benasque Workshop (and School) on TDDFT, since 2004.
Continue reading 7th School & Workshop on Time Dependent Density Functional Theory: Prospects and Applications

Scientific Report regarding the CECAM Workshop: “Tailor-made 2D-materials and functional devices”


Thomas Heine, University of Leipzig (Germany)

Yandong Ma, Jacobs University Bremen (Germany)

Tim Wehling, University of Bremen (Germany)

Young-Hee Lee (Institute for Basic Science, Suwon (Korea)

Thomas Frauenheim, University of Bremen (Germany)



University of Bremen, Germany, 27th June until 1st of July 2016


I. Summary

The workshop “Tailor-made 2D-materials and functional devices” was held at the University of Bremen, Germany from June 27th to 1st 2016. In total, 76 participants from Belgium, Brazil, Finland, Ireland, Luxemburg, The Netherlands, Portugal, Slovenia, Spain, Sweden, Switzerland, Denmark, France, Germany, UK and US attended the workshop.

The programme consisted of 30 invited lectures, one poster session presenting 37 posters and many events (reception / conference dinner) to allow for informal exchange. The lectures were scheduled to last 40 min, including 5-10 min discussion time. In addition to this extended time for discussion, the chairpersons were instructed to introduce the subject of the session and to actively participate in the discussion. This “Gordon-conference-style” was essential to guarantee a vivid discussion. The organizers ensured that well-established scientists acted as invited speakers and chairpersons.

Concerning the poster session, we accepted only 37 posters to allow for an intense exchange of ideas at each single poster. Here, we encouraged in particular the young scientists to ask questions. The participation of PhD students was supported by partly covering local accommodation costs.

Due to the compact organization and accommodation in one hotel only all participants stayed together for the whole time of the conference, which additionally enforced the scientific discussion which was mandatory since scientists from various separated fields, i.e. advanced quantum chemistry, many-body perturbation theory, DFT and beyond, scanning probe techniques, optical spectroscopy, ARPES, etc. were attending the meeting to merge ideas and formulate a common goal for future directions and collaborations of theory groups with experimental groups.

Financial support from the DFG, Psi-k Network, and the German CECAM node multi-scale modelling from first principles, and the University Bremen is gratefully acknowledged.

Continue reading Scientific Report regarding the CECAM Workshop: “Tailor-made 2D-materials and functional devices”

17th Workshop on Dynamical Phenomena at Surfaces

Report on the WDPS-17 workshop held in Milan, Italy, from Sept. 19th to 21st, 2016.

WDPS logo

The Workshops on Dynamical Phenomena at Surfaces (WDPS) are an active biennial series of scientific workshops that deal with dynamical aspects of surface behaviour. A special characteristic of the series is the emphasis on bringing theory and experiment together in an intimate setting, a feature that was initiated by in the first meeting of the series. The present workshop combined an exceptional setting with a programme that balanced experimental and theoretical talks, as before; however, the scientific context was expanded significantly in 2016. In the first meeting of the series, in 1983, the topic focussed exclusively on surface phonons and indeed the emphasis within that topic was a single experimental technique, namely inelastic helium atom scattering. Both the experimental technique and the tools for theoretical analysis were under active development at the time and that emphasis was reflected in the title of the first workshop, SURPHON.

The Milano workshop touched on neither topic though there were contributions on more recent developments in molecular beam scattering. The overall impression was one of a greatly expanded scientific activity within a thriving community. Topics varied from understanding bio-systems and nano-friction to macro-molecules, self-assembly and the diffusion dynamics of complex systems, all from an atomistic perspective. The dramatic evolution of scientific breadth displayed in the present meeting is a reflection of the vigour that exists in the community today. Everyone looks forward to the next meeting in the series, which was advertised as to be held in Orlando, USA, in 2018.

WDPS-17 group photo

Continue reading 17th Workshop on Dynamical Phenomena at Surfaces

Psi-K Quantum-ESPRESSO School on Ab-Initio Thermal Transport


Ab-initio prediction of thermal properties for condensed matter has been a blossoming field in the last few years, thank to its numerous applications mainly in thermoelectric materials and heat dissipation technologies. This methodology however does require to master a certain amount of expertise, both technical and theoretical, in order to be executed rigorously and efficiently. In this school, we wanted to provide an in-depth view of the theoretical framework, without neglecting the importance of applying the theory on some practical examples.

The school has been composed of theory sessions and hands-on tutorials suitable for anybody with graduate-level knowledge of condensed matter physics. As we planned to release all the software with an open-source license just after the end of the school, it was extremely useful for us to collect some feedback from this first batch of users.
Continue reading Psi-K Quantum-ESPRESSO School on Ab-Initio Thermal Transport

Hermes 2016. Multiscale modelling and science communication

Hermes 2016
Hermes 2016 – demanding workshop had drained all the seriousness from the participants and organisers.


Erich Wimmer’s key note talk kick started a summer school on multi-scale materials modelling and science communication. Erich shared an exciting story of his personal journey and work in the field of computational materials science – with experience in academia, industry and even running a company (a co-founder at Materials Design).

A human element shone throughout the talk, emphasising  the importance of collaboration and the relationships between colleagues for making the numerous advances in the field possible, and importantly making the process fun and rewarding.

Following the Q&A session informal discussions continued over the dinner in the beautiful dining halls of the Cumberland Lodge. The evening ended with an informal ice-breaking game of treasure hunt, allowing the participants to relax, explore the great Windsor Park and the lodge itself while getting to know each other. Demanding several days awaited – a series of master classes each focusing on time/length scale beyond the familiar grounds for most of the participants; a series of work shops on engaging presentations, communication through infographics and a technical session on data visualization using Mathematica leading to group projects and individual presentations. Continue reading Hermes 2016. Multiscale modelling and science communication

College on Multiscale Computational Modeling of Materials for Energy Application

From the 4th to the 15th July, over 90 scientists from 30 countries have gathered at the Abdus Salam ICTP in Trieste, Italy, to attend the College on Multiscale Computational Modeling of Materials for Energy Applications. This college had the goal to put together experts in multiscale modeling from the atomistic scale up to the macroscopic continuum. The idea is that multiscale modeling is necessary because of mutual interdependence of processes taking place at very different length and time scales. Therefore, only a multiscale approach is able to provide insight into the effect of microscopic processes on the actual device performance and stability, and to provide understanding and guidance relevant to process and device optimization, also in an industrial context.

The college consisted of theoretical lectures on the computational methods, hands-on sessions to get practically acquainted with techniques and codes, seminars on current materials challenges in the energy sector held by leading experts from academia and industry, and seminars on career development.

Continue reading College on Multiscale Computational Modeling of Materials for Energy Application

13th ETSF Young Researchers’ Meeting (London)


For 13 years now ETSF has encouraged young researchers to take part in the ETSF Young Researchers’ Meeting (YRM). This event which is organised by young researchers for young researchers made its way to London for the first time, as always the high standard of talks encouraged much debate and discussion among the attendees while enjoying all that London has to offer (for a brief moment we had some sun too!!!).

Continue reading 13th ETSF Young Researchers’ Meeting (London)

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