First XLIC Training School will take place in Zaragoza, at the premises of Z-CAM (http://www.z-cam.es/). It will be organized in two modules of one week each. Attendees can participate in one or both of them.
- Module 1. March 9-13, 2015
Molecular Excited States (Download tentative program)
- Module 2. March 16-20, 2015
New Computational Methods for Attosecond Molecular Processes (Download tentative program)
Registration should be done through CECAM website and separately for each module. When registering, please, do not forget to mention the XLIC node at which you are affiliated and the estimated cost for your travel expenses. Deadline for applications is January 31st, 2015.
Trainers will carry out a selection on the basis of the candidates’ CVs and inform them on the selection results at the latest by February 6th, 2015.
Financial support: XLIC Action will offer grants to partially cover the participation of young researchers involved in the Action. The number of grants and amount will depend on the number of requests for funding.
Further details on the school and registration details can be found here
STSM by Klavs Hansen, Institut for Fysik og Astronomi (DK) with Yoni Toker, Bar Ilan University (IL)
On December 23-29, 2014 (7 days)
From DENMARK to ISRAEL
Free flying anionic SF6 cluster BIRD
Clusters are usually produced in a range of sizes and often some specific sizes, called magic numbers, are more abundant than others. These patterns can often be interpreted in terms of electronic or geometric shell structure. There is, however, no one-to-one correspondence between stability and abundances, and the elucidation of the stabilities require a more subtle analysis. Such an analysis has been performed on abundances of anionic SF6 clusters.
Although the size-to-size variations are strong, typically a factor of two indicating significant stability variations, the abundances show no strong signature of shell structure. Because the SF6 molecule in many circumstances can be described as a sphere it was expected that the pattern would have close similarities to the abundance spectra of noble gas clusters with strong peaks at N=13 and N=19. However, no less than nine maxima appear in the range N=2-30.
The inversion procedure converting abundances to evaporative activation energies identified stable clusters at the sizes N=3, 10, 12, (13), 15, 21. This pattern is not yet understood. Previous results from the Israeli group on the cationic counterparts will provide clues to the role of the charge in the structure of these clusters. Another tool will be molecular structure simulations at finite excitation energies, which are under way at Bar Ilan University. An extension of the analysis will include the metastable decays to obtain heat capacities and the radiative black body heating of the clusters at long measurement times.
It is intended to continue the collaboration, with priority to an application of the methods to CO2 clusters.
Gas phase absorption of Chlorophylls
Chlorophylls are a key ingredient for life on earth. They are the main pigments used in photosynthesis – a process in which sunlight is converted into chemical energy needed for life. Chlorophylls have two main absorption bands in the blue and red regions of the visible spectrum which are known as the Soret and Q-bands. In order to separate the intrinsic absorption of the chromophores from shifts induced by the environment, and for direct comparison with high level quantum calculations photo-absorption measurements of the truly isolated chromophores. These measurements have now become possible to conduct with action spectroscopy.
During the STSM we measured the Soret band (300-450nm) of Chl a and Chl b, with three different ligands tetramethylammonium (NMe4+), tetrabutylammonium (NBu4+) and acetylcholine. The measurements were conducted in Prof. Steen Brøndsted Nielsen SEP-I laboratory in the institute of physics and Astronomy in Aahrus University. Complexes of Chl a or Chl b with a ligand have been electrosprayed, accelerated mass-selected using a magent, irradiated by a tunable laser and then passed through an electrostatic analyzer. When the chlorophylls absorbs the laser, the bond between chlorophyll and ligand dissociate. By monitoring the number of counts on the detector as a function of laser wavelength we deduce the absorption band.
The measured Soret bands of Chl a (maximum at 404 nm) with the three different ligands are shown in Figure (left). We find that the absorption band does not depend on the choice of ligand, but is blue shifted compared with the absorption of Chl b (maximum at 409 nm), as seen if Figure (right).
We believe the result of this STSM will help establish an understanding of the intrinsic absorption of Chlorophylls molecules which in turn can be used to understand environment perturbations such as excitation coupling and axial ligation.
STSM by Zdenek Masin, The Open University (UK) with Olga Smirnova, Max Born Institute, Berlin (DE)
On October 19th, 2014 (15 days)
From UNITED KINGDOM to GERMANY
High Harmonic Generation from pyrazine
Irradiation of an atom or a molecule by an intense laser pulse leads to the emission of photons with frequency that is an integer multiple of the frequency of the laser field. This is the high harmonic radiation. The spectrum of the radiation depends sensitively on the sub-cycle dynamics in the ion and can be used as a sensitive probe of the electronic and nuclear dynamics. The aim of our collaboration is to construct a theoretical model for the High Harmonic Generation (HHG) for the biological molecule pyrazine.
Our theoretical description is based on the well-known three-step model of HHG. This STSM has allowed us to complete the set of data required to construct the model: transition dipole matrix elements, ionization amplitudes for the low-lying states of the pyrazine cation (carried out by Serguei Patchkovskii, MBI) and the sub-cycle laser-induced dynamics in the cation.
The transition dipole matrix elements were obtained using the UKRmol suite, the UK implementation of the molecular R-matrix method. We have benchmarked our calculations against the known photoionization cross sections for pyrazine. Our results show the strong role of correlation in the photoionization dynamics involving the deeper lying valence states: the scattering model using ~5000 configurations significantly underestimates the partial photoionization cross sections for these states. In order to obtain accurate cross sections for these states a much larger set of ~135000 configurations was needed.
Combining all the obtained data our preliminary analysis has identified several interesting channels that may play role in the process of HHG: ionization into the cationic ground state with recombination into the second excited single-hole state (B1u) and vice versa. However, the potentially most interesting dynamics involves a low-lying satellite state of B2u symmetry: ionization into the satellite state with recombination into the cationic ground state.
Finally, we have developed routines for the UKRmol suite that allow us to visualize the Dyson orbitals produced by the CDENPROP module, see Figure 1.
Further collaboration will focus on analysis of the role of the different cross channels and on generation of the harmonic yields.
Figure 1: Dyson orbitals for ground state of pyrazine cation, 1 Ag, and its two lowest-lying excited single-hole states: 1 B1g, 1 B1u. For each cationic state the label in the parentheses corresponds to the singly occupied molecular orbital in the most dominant configuration in the CAS-CI expansion of the wavefunction.
STSM by Sandra Gomez, Complutense University of Madrid (ES) with Volker Engel Institut für Physikalische und Theoretische Chemie der Universität Würzburg (DE)
On November 23rd, 2014 (5 days)
From SPAIN to GERMANY
Strong field decoupling of nuclear dynamics
The interaction of molecules with strong laser fields produces molecular dynamics much more complicated than in the presence of weak fields. The solution for structureless two-level systems in a single frequency field is known as Rabi solution and the population of states oscillates at the Rabi frequency, known as Rabi oscillations or Rabi floppings.
When this system is replaced by two electronic states with dependance on nuclear coordinates, the Rabi oscillations decay on time while the nuclei are moving due to a dephasing that damps electronic coherences.
The goal of our collaboration is to minimize these effects by decoupling as much as possible the nuclear motion.
During the short visit we discussed possible models where these effects could be observed, we generated the potential energy curves of some diatomic molecules (Na2 and NaI) and we started to study how to analyze the dynamics using hamiltonians of coupled electron-nuclear motion (beyond Born-Oppenheimer approximation).
Due to the short time availiable, only the transition between ground and first excited state of Na2 molecule was studied at different amplitudes of the laser field (continuous wave laser).
We plan to extend these results to systems with other decoherence processes, as the NaI predissociation and to control of coupled nuclear and electronic degrees of freedom.
Multiphoton ionization with a tunable UV laser allows measuring excited state adiabatic energies of DNA bases
The group of Samuel Eden at the Open University Milton Keynes is expert in the field of irradiation of biomolecules and clusters by lasers and electrons. In particular, they probe the influence of nanohydration and clustering on the fragmentation of DNA and RNA bases in the gas phase. Recently, they discovered a microsecond-timescale dissociation channel from isolated uracil and thymine after UV-multiphoton ionization, with an unexplained wavelength threshold. The aim of this STSM was to investigate further this intriguing observation.
We measured the mass spectrum of thymine after UV multiphoton ionization as a function of wavelength, and obtained a threshold of 224 ± 0.5 nm (5.53 ± 0.02 eV) for the metastable dissociation channel (HCNO loss). Our hypothesis is that this threshold corresponds to accessing the S1 state with vibrational excitation matching the energy difference between the ionic ground state (8.82 ± 0.03 eV) and the dissociative ionic state leading to HNCO loss (10.70 ± 0.05 eV) 1, yielding an S1 adiabatic energy of 3.65 ± 0.07 eV. This value agrees with the most recent DFT calculation: 3.72 eV 2. Preliminary results on Adenine-Thymine clusters also suggest a stabilizing effect on the S1 state due to clustering.
Furthermore, we also carried out experiments on cytosine, and observed metastable dissociation, thus demonstrating that measurement of metastable channel wavelength threshold is a possible tool to measure S1 adiabatic energies. We will write a journal article in early 2015 including data from the STSM as well as the host group’s follow-up measurements. We will also arrange further collaborative experiments in the near future with the aim of probing electronic excitation and ionization induced processes in isolated and clustered amino acids.
(1) Jochims, H. W.; Schwell, M.; Baumgärtel, H.; Leach, S. Chemical Physics 2005, 314, 263.
(2) Etinski, M.; Marian, C. M. Physical Chemistry Chemical Physics 2010, 12, 4915.
In a European FP7 project (MoWSeS), SCM has a job opening available immediately for a theoretical physicist or chemist with a talent for method and software development,to extend our Time-Dependent DFT capabilities to study the optical properties of two-dimensional semiconductor materials such as MoS2.
The EU position offers attractive salary and benefits and SCM and the Theoretical Chemistry group form a stimulating experienced research environment for this topic.
The ideal candidate would be a theoretical physicist or chemist who has already programmed in large DFT codes and has a working knowledge of Time-Dependent DFT.
Eligibility criteria cap the research experience and impose that this is a first or perhaps second postdoc position.
Applications are welcomed at email@example.com as soon as possible (absolute deadline January 31st 2015).
For further details on the project and the application details, see: http://www.scm.com/PostDoc2D-TDDFT
The Institute of Physics of Rennes (IPR), a joint research unit between University Rennes 1 (UR1) and CNRS, is the main multidisciplinary physics laboratory in west of France. The team working on photoinduced phenomena is seeking candidates to fill an associate professor position to reinforce and develop its expertise.
The successful candidate will focus on performing ultrafast studies of photoactive materials and molecules, using home-based equipments as well as large facilities such as synchrotrons and X-FELs.
As associate professor, the successful candidate will also teach in physics and mechanics from bachelor to master levels
The position will be open:
– to candidates already occupying associate prof. position (or MCF)
– to researchers who have obtained the french “qualification aux fonctions de maître de conférences”
The position should be open soon with a deadline for application at end of March. However, we invite interested candidates to rapidly contact us.
Recent papers and more information on the research activities can be found here:
Eric Collet, Marco Cammarata and Maciej Lorenc
Tel : +33 2 23 23 65 32
The International Max Planck Research School for Ultrafast Imaging & Structural Dynamics (IMPRS-UFAST) is a structured postgraduate programme offering 15 fully-funded Ph.D. positions for admission in 2015.
Fellows should start in 2015. Have you graduated or are you about to graduate with a Master degree or equivalent? If you are a physicist, chemist, molecular biologist or nanoscientist with excellent grades, we would very much like to hear from you.
Research: Our research focuses on ultra-intense electron and x-ray sources for directly observing atomic motions during primary events, and ultrafast imaging over the relevant length and time scales to come to new levels of understanding of the interplay between structure and dynamics.
Specific areas include theoretical and experimental aspects of condensed matter and atomically resolved dynamics, fundamental light-matter interaction, accelerator-based light sources, coherent imaging, coherent controlled molecular and solid state dynamics, molecule imaging, extreme timescale spectroscopy, ultrafast optics and x-ray science, relevance and applications in chemistry, biology and medicine.
- a 3-year PhD programme with cross-disciplinary thesis research in a vibrant, international scientific environment
- supervision and mentorship by a team of internationally renowned experts and additional support through an advisory panel
- State-of-the-art research facilities
- advanced training opportunities (scientific, skills, career) in English
- funding in form of stipends or contracts
- Travel budget and funding for German language classes
Apply: Applications must be submitted online at our website www.imprs-ufast.de. The deadline is 25th January 2015. PhD projects start in summer/autumn 2015. We look forward to hearing from you!
Please address your questions to Dr. Sonia Utermann at firstname.lastname@example.org.
About: The International Max Planck Research School for Ultrafast Imaging & Structural Dynamics (IMPRS-UFAST) is a joint venture of the Max Planck Institute for the Structure and Dynamics of Matter, Deutsches Elektronen Synchrotron (DESY), the Universität Hamburg and the European XFEL GmbH.
Postdoctoral and PhD positions are available at the Laboratory of Computational Chemistry and Biochemistry of the Swiss Federal Institute of Technology EPF in Lausanne, Switzerland.
The successful candidates will be involved in the development and the application of
1) Time-dependent density functional (TDDFT) based excited state dynamics of ultrafast phenomena in physical, chemical and biological systems
2) Classical and mixed quantum mechanical/molecular mechanical (QM/MM) simulations of dye-sensitized and perovskite based solar cells
Both projects are part of National Competence Centers (NCCR) and are performed in close collaboration with experimental groups.
Ideal candidates have a background in computational physics, condensed matter theory, computational material science or computational chemistry and some programming experience.
Prospective candidates are invited to contact:
Prof. Ursula Röthlisberger
Laboratory of Computational Chemistry & Biochemistry
Institute of Chemical Sciences and Engineering
Ecole Polytechnique Federale de Lausanne EPFL
CH-1015 Lausanne, Switzerland
phone: ++41-21-693 0325
fax: ++41-21-693 0320