Organizers:

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,

10^th until 14^th 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” →

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

INTRODUCTION
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.
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Organizers:

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)

Location:

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

I. Summary

The workshop “Tailor-made 2D-materials and functional devices” was held at the University of Bremen, Germany from June 27^th to 1^st 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, cecam-mm1p.de and the University Bremen is gratefully acknowledged.

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

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

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.

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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.
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From the 4^th to the 15^th 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.

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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) →