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.

TSRC TDDFT Summer School and Excited States Workshop

The first US-based summer school and workshop on Time-Dependent Density Functional Theory (TDDFT) was held July 11-21, 2017 in Telluride, CO. TDDFT is increasingly used in
computational molecular and materials science to calculate electronic-excitation spectra and dynamics in a wide variety of applications, including photocatalysis, photo-controlled bond dissociation, and light-induced charge transfer. Software development in this community targets multiple software packages, many of which are open source, such as octopus, NWchem and [email protected], which are the ones our school focused on. The goal of this first iteration was to create a home for a national community of scholars, including users and developers, with a deep understanding of TDDFT, its capabilities, limitations, and high-performance computing context. We used this opportunity to explore interest in such an event in the future and based on overwhelmingly positive feedback from students and teachers, we intend to hold a similar school+workshop every two years in the US, in order to maintain the high level of interest that we witnessed and the enthusiasm amongst participants.

Read the full workshop report here.

Scientific report on the “Total Energy and Force Methods 2018” Workshop

Workshop logoTotal Energy and Force Methods 2018
Selwyn College, Cambridge, UK
9th – 11th January 2018

Organisers: Chris Pickard (University of Cambridge), Gábor Csányi (University of Cambridge), Mike Payne (University of Cambridge), Richard Needs (University of Cambridge), Michiel Sprik (University of Cambridge); External advisor: Mike Finnis (Imperial College London).

Funding: Psi-k, CCP9, the UKCP Consortium and the EPSRC CDT in Computational Methods for Materials Science.


This event was the latest in the “mini” series associated with the “Total Energy and Forces” workshops, held at ICTP in Trieste every two years. Since 1987 the Trieste workshops have taken place in odd-numbered years, alternating with the mini workshops, held each even-numbered year in a different location. The most recent workshops of the mini series took place in Madrid (2000), Tenerife (2002), Paris (2004), Cambridge (2006), Bonn (2008), Shanghai (2010), Barcelona (2012), Lausanne (2014) and Luxembourg (2016).

The workshop focused on the most recent developments in the field of electronic structure methods from the first-principles perspective, their diverse applications and mathematical foundations. The numerous approaches that are developed and used in the electronic-structure community provide the foundation for computing many physical and chemical properties of solids, liquids, and low-dimensional systems. However, there are numerous challenging applications for which the level of approximation is insufficient or where computational costs are prohibitive for accurate quantitative prediction of material properties. Therefore, continued efforts are devoted to an improvement of existing methods and the development of new methods.

Continue reading Scientific report on the “Total Energy and Force Methods 2018” Workshop

Anharmonicity and thermal properties of solids

10-12 January 2018, Paris, Institut Henri Poincaré

Conference organizers
Francois Bottin (CEA-DIF, France)
Johann Bouchet (CEA-DIF, France)
Matthieu Verstraete (University of Liege, Belgium)
Olle Hellman (California Institute of Technology (Caltech, US)

The quantitative prediction of harmonic phonon frequencies and thermodynamical quantities is one of the great successes of atomistic electronic structure in the past 30 years. Reality is however more complex, and vibrations are never purely harmonic. The systematic calculation of all possible anharmonic processes is a daunting task. Anharmonicity influences many important phenomena such as thermal expansion and Fourier’s law or coherent phonon generation. Heat transport is a central pillar of solid state physics and engineering, and influences many devices and properties. Both low and high conductivity materials have their uses, but historically its control has proved elusive. Simple mechanistic (grind it up) or back of the envelope (make it heavy) models reached their limits years ago. But only in the past 10-15 years a full chemically specific and atomistic prediction of lattice thermal properties has become possible. The field has blossomed at the crossroads of Chemistry, Physics, Engineerings (Energy, Mechanical, Electronic etc…), and benefi tted from a positive feedback loop
through re fined experiments and novel theories.

The aim of this workshop is to bring together cutting edge researchers in the numerical simulation and experimental determination of anharmonic phonon dynamics, and related properties (transport, ultrafast, electrons), to foster new approaches, new ideas, and give the field a decisive kick forward. We anticipate intense discussions and hotly contested debate about
where to go from here, as the terrain is wide open.

Read the full report here.

International Workshop on Ab initio Description of Iron and Steel: Mechanical Properties (ADIS2016)

The series of ADIS workshops is inspired by the impressive variety of competing mechanisms on the microscopic/atomic scale, which determine the performance of engineering materials such as steels. Accordingly, the main scope of the workshops is a thorough and detailed discussion of this behavior, in order to understand the underlying physics and to contribute to a further systematic improvement of the materials. We are convinced that a truly predictive approach to materials modeling needs to be based on a fundamental ab initio level, rooted in the laws of nature rather than empiricism. This is also the driving force for the collaborative research centre SFB761 Steel ab initio, which is devoted to a quantum-mechanically guided design in high- and medium-Mn steels and funding this workshop. We are grateful that the importance of this development is further recognized by the Psi-k Charity, which is financially supporting ADIS2016. Continue reading International Workshop on Ab initio Description of Iron and Steel: Mechanical Properties (ADIS2016)

scientific report on the Psi-k workshop “2D layered materials for opto-electronics: a theoretical/computational perspective”

                                       Rome, Italy, 18-19 December 2017


-Maurizia Palummo, Physics Department Tor Vergata University, Rome, Italy

-Giacomo Giorgi, Department of Civil & Environmental Engineering (DICA) University of Perugia, Italy

-Jeffrey Grossman, Materials Science Department MIT, Boston, USA

Funding:  Psi-K


Isolating graphene for the first time in 2004, with its plethora of possible device⎯oriented appealing features, has paved the way towards the study of several new classes of layered two-dimensional (2D) materials.    In several opto-electronic applications such as those involving the solar-to energy conversion process, it is indeed extremely appealing to control the properties of well-understood 3D materials by reducing their dimensionality towards the 2D limit or, even better, to directly focus on naturally layered materials both free⎯standing and also coupled with other layered ones in order to boost the sunlight conversion efficiency. Moreover, stacked Van der Waals (vdW) heterostructures of 2D monolayers offer a unique playground to engineer the opto⎯electronic properties towards the realization of devices with different functionalities and with the availability of metallic, semiconducting, and insulating materials.  Due to their high surface to volume/ratio 2D⎯layered materials can harvest solar energy and generate electrons and holes, and they can also provide paths for the separation and diffusion of the photo-excited carriers. These are fundamental prerequisites for the realization of any photo⎯catalytic or photovoltaic cell.  The use of these emerging two-dimensional layered materials in technological applications presupposes a detailed knowledge of their chemical and physical properties. Theoretical methods and simulations play a fundamental role for the understanding and predicting these properties.  The goal of the workshop, collecting distinguished scientists in the field, has been to clarify the theoretical microscopic understanding of layered 2D Materials with a particular focus on applications in opto-electronics and solar⎯to⎯energy conversion.  An overview of the research at experimental level from experts in the field has also been given. Continue reading scientific report on the Psi-k workshop “2D layered materials for opto-electronics: a theoretical/computational perspective”

Scientific report regarding the CECAM Workshop: “Charge carrier dynamics in nanostructures: optoelectronic and photo-stimulated processes”

Organizers:   Thomas Frauenheim (University of Bremen, Germany)

Oleg Prezhdo (University of Southern California, Los Angeles, US)

Christoph Lienau (University of Oldenburg, Germany)

Chiyung Yam (Computational Science Research Center, Beijing, China)

Location:       University of Bremen, Germany,

9th until 13th of October 2017

  1. State-of-the-Art Summary

Advances of time-resolved experimental techniques, needed for a detailed understanding of charge carrier dynamics as they occur in real time, require matching progress in theoretical approaches. Applications to novel, emerging nanoscale materials, which ultimately lead to faster, more efficient and miniaturized devices, pose multiple theoretical challenges. Modeling time-resolved experimental data becomes a major goal of a theorist.

The proposed workshop became a forum to brainstorm ideas about solutions to important computational problems, and identify new directions for time-dependant electronic structure method development and challenging applications. In this way, we have been able to create an exchange mechanism to unite a core of developers in an interactive environment, in order to initiate design of a new generation software tools for quantum modelling of realistic complex systems and nanostructures in electronic ground and excited states. The delivery of this technology to a broad community will facilitate breakthroughs on high-impact materials science problems.
Continue reading Scientific report regarding the CECAM Workshop: “Charge carrier dynamics in nanostructures: optoelectronic and photo-stimulated processes”

Scientific report on the CECAM/Psi-K workshop on “Quantum-chemistry methods for materials science”

CECAM-HQ-EPFL, Lausanne, Switzerland, 08-10 November 2017

OrganizersIgor Ying Zhang and Matthias Scheffler (Fritz Haber Institute of the Max Planck Society (FHI), Berlin, Germany).

Sponsors:  CECAM, Psi-k and Fritz Haber Institute of the Max Planck Society (FHI), Berlin, Germany.


The workshop “Quantum-chemistry methods for materials science” was held at Lausanne, Switzerland from Nov 08th to 10th 2017. In total, 22 participants from Europe, USA, and China attended the workshop. The workshop stimulated an interdisciplinary exchange of ideas and knowledge about the development of advanced electronic-structure methods transferring from chemistry, solid-state physics, and materials science.
Continue reading Scientific report on the CECAM/Psi-K workshop on “Quantum-chemistry methods for materials science”

Scientific report on the “Interface Morphology Prediction with Robust and Efficient Structure Search” (IMPRESS) Workshop

Interface Morphology Prediction with Robust and Efficient Structure Search (IMPRESS)

Aalto University, Finland, 7-9 June 2017

Organisers: Dr Milica Todorović (Aalto University, Finland), Dr Oliver T. Hofmann (Technical University of Graz, Austria), Prof. Patrick Rinke (Aalto University, Finland)

Funding: CECAM, Psi-K, NOMAD CoE, Aalto University CMMP doctoral network


Determining or predicting the structure of organic ensembles on surfaces is a challenging problem that occupies basic science and engineering alike. Recently, novel machine-learning approaches have started to compete with more traditional, stochastic methods, such as basin hoping or simulated annealing. In IMPRESS, we took an interdisciplinary stance and brought together assorted experts to focus on the challenges of organic/inorganic interfaces: this is the first workshop to unite different electronic structure methods, structure search approaches and machine learning.

Continue reading Scientific report on the “Interface Morphology Prediction with Robust and Efficient Structure Search” (IMPRESS) Workshop

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