Tobias got a stipend

Good news for our group: Tobias Möhle, who has defended Master thesis this year, has got a stipend from the government of Mecklenburg-Vorpommern to support his Ph.D. project. He was lucky to be one of nine students chosen this year. The funding is supposed to be for one year with the possibility of prolongation for another year. The project of Tobias goes along the lines developed in his Master thesis and is devoted to further development of versatile tools for the photoelectron spectroscopy in the weak-field regime. The primary focus is put on the reliable representation of the wave function of the photoelectron leaving the molecule. Congratulations and good luck!

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XTRAM 17

People living in central and northern Europe may have noticed that this summer has been way colder than the average. That is why I was happy to get an invitation from Nadja Doslic, one of the organizers of XTRAM17 summer school, to sunny Sicily at the end of July.

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The place of the conference was absolutely fantastic – it was a small ancient town Erice on top of the mountain overlooking the mostly champaign landscape of western Sicily. Despite its distal location, Erice is a scholarly center, where many of the scientific schools and conferences take place at the same time. The whole infrastructure of the town is adapted not only for crowds of tourists but the constant presence of conference attendees as well. The center of the scientific life in Erice is Ettore Majorana Center. Many of famous scientists such as Feynman, Wigner, Dirac, and many others have been reading lectures within the walls of this center. According to center’s website “Every year since 1963, authors of new discoveries and inventions come to Erice; 85 of them were awarded the Nobel Prize after their participation to the EMFCSC activities and 49 were already Nobel laureates.” Remarkably, the walls of the lecture hall are decorated with artistic depictions of Feynman diagrams. I hope you can imagine the supportive atmosphere of this meeting.

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Enough said about the place, but the meeting itself deserves positive comments as well. The abbreviation XTRAM is short for “School on X-UV time-resolved advanced methods” and is supported by the EU. Frankly speaking, this was a rare event when the scientific program was that relevant and interesting to me that I could not even decide which talks to skip to carve out time to prepare for my own lecture. Moreover, this was a nice opportunity to meet with people whom I did not know before. I think it is not a secret, that scientific community clusters around some prevailing topics and some cores of affluential researchers, who determine the agenda in each subgroup. Often, communities dedicated to the same subject overlap very little, and one can see publications where people cite works of their peers belonging to the same cluster, without knowing (or just ignoring) the others. Luckily, I have learned a lot about research going on in the community with which I am not that actively interacting but which deals with problems very related to my research. And of course, it was nice to talk and exchange ideas with people whom I know.

It is tough to select my favorites among the talks because they all were exciting. I was very interested to see how scientist working with non-equilibrium Green’s functions, Andrea Marini, Claudio Verdozzi, Enrico Perfetto, are treating electron dynamics of photoionization and Auger decay. There were also some talks on spintronics by Peter Eliot, Marco Battiato, Flavio Capotondi, as well as on electron dynamics treated with real-time TDDFT. For me, the talk by Martin Beye on recent progress in stimulated resonant inelastic X-ray scattering was very encouraging, since I consider this method as the primary experimental tool to examine ultrafast spin-dynamical effects, which are the main subject of my recently accepted project. This workshop provided me with an excellent overview of activities in the field and supplied me with a vast amount of information and literature which I would need to digest for months.

I should also mention lectures by Jesper Norell, Michael Odelius, and Philippe Wernet reporting the highlights of their recent and very prominent work representing a nice combination of novel experimental and theoretical tools in the field of time-resolved X-ray spectroscopy (see, e.g., nice this article). My own lecture was mainly devoted to ultrafast spin-dynamics in the core-excited states as it was explicitly requested by the organizers.

I would also like to thank Nina Ignatova, Jesper Norell, Vlad Kochetov, and Michael Odelius for nice time spent together in Erice. It was not only fun, but I hope should also promote our joint research.

DFG project accepted!

I would like to invite you for the piece of virtual cake!

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What’s the reason for that? Two days ago I have got an approval of my DFG project entitled “Soft X-ray spectroscopy and correlated many-electron dynamics of molecular systems from first principles theory”. (For those who don’t work in science in Germany, DFG (Deutsche Forschungsgemeinschaft) stands for German Research Foundation.) This project goes along the lines of our recent publications in Physical Review Letters and Molecular Physics which served as a preliminary work basis for the project.  It includes my own research position and a Ph.D. student for 3 years as well as money for the midterm workshop.

Remarkably, I was pleased to get excellent reviews, and what is surprising, referees even give me encouraging pieces of advice how to promote my scientific career and use the financial support from DFG in the most efficient way.

The chocolate cake was made by my wife Olga and decorated with the basic working expression for this project. It was successfully annihilated by my colleagues, that is why I can suggest you only its virtual counterpart. Nice offer, zero calories!

Website of Christoph Merschjann

Christoph Merschjann, a colleague, who has been working in Rostock in the group of our experimental collaborator Stefan Lochbrunner and then moved to the group of our collaborator Emad Aziz in Berlin, has created a new personal website. Please enjoy!

An interesting fact is that we have not done any joint study while working nearby, but our collaboration was quite fruitful when Christoph changed for Helmholtz-Zentrum and resulted in a recently published paper.

 

Transient photoelectrons and linkage isomerism

Linkage isomerism is a well-known phenomenon in coordination chemistry. Multiatomic ligands can bind to a central metal atom with either of their ends. In some compounds, ligands can undergo a change of their orientation upon absorption of light. This effect can be used to, e.g., store information and energy. The prominent example is nitroprusside anion [Fe(CN)5NO]2-, where NO+ moiety changes from Fe-NO orientation to a side-on one with both N and O bound to iron. In the recent work, we have applied both transient photoelectron spectroscopy and theoretical modeling to reveal the ultrafast kinetics of this process:

A.A. Raheem, M. Wilke, M. Borgwardt, N. Engel, S.I. Bokarev*, G. Grell, S.G. Aziz, O. Kühn, I.Yu. Kiyan, Ch. Merschjann, E.F. Aziz Ultrafast kinetics of linkage isomerism in Na2[Fe(CN)5NO] aqueous solution revealed by time-resolved photoelectron spectroscopy Structural Dynamics 4, 044031 (2017)

Nuclear vibrations in X-ray spectra with a fine-tooth comb

One might remember the post where I have written about nuclear correlation effects showing up in absorption and resonant inelastic X-ray scattering spectra. A few days ago we have published a follow-up article, where this effect is scrutinously dissected:

Sven Karsten,  Sergey I. Bokarev,  Saadullah G. Aziz,  Sergei D. Ivanov, Oliver Kühn A time-correlation function approach to nuclear dynamical effects in X-ray spectroscopy J. Chem. Phys. 146, 224203 (2017).

X-ray nuclear dynamics

In the article, you can find an explicit derivation of the time-domain working expressions, a detailed description of our protocol, loads of formulas and graphs – the whole nine yards. Fans of math should do appreciate Sven’s efforts. Even more important, it represents a critical view of the method and suggests the route how to improve the main pitfalls of classical approximation with moderate effort.