The 3rd XLIC General Meeting will include also the 2nd Young Scientist Forum (YSF) – a special half-day with talks given by young researchers (PhD students and post-docs). The talk format will be 15 minutes + 5 minutes of discussion.
Seven young speakers will be selected by the young scientific committee on the basis of the submitted abstracts. The presenting author should attach also a short CV (including information about education, oral presentations and publications). For YSF talk, an abstract has to be submitted before September 15th, 2015.
Moreover, during the meeting, two special poster sessions are foreseen in order to exchange views and stimulate discussion on research topics, and to support interdisciplinary communication between the researchers. All young researchers participating in the XLIC General Meeting are encouraged to present a talk and/or poster.
The length of the abstract is limited to one A4 page, including figures and tables (see http://xlic.unideb.hu/abstracts).
The selection of young speakers will be announced on September 25th, 2015.
The 3rd General Meeting of the COST Action CM1204 “XUV/X-ray light and fast ions for ultrafast chemistry (XLIC)” will be held from 2 to 4 November, 2015 in Debrecen, Hungary. At the end of the first day (around 17 h. ) we will have the 4th XLIC Management Committee meeting, where the main advances of the Action and future directions will be examined.
The conference will consist of 24 lectures given by invited speakers, 12 oral presentations by young scientists as well as 2 poster sessions. More information can be obtained in the meeting website: http://xlic.unideb.hu/
Registration: There is no registration fee to attend the meeting but participants must register filling the corresponding form before September 20th, 2015.
Accomodation: Due to the intended all-under-one-roof format of the meeting, all participants are strongly advised to stay in the Centrum Hotel, where the conference will take place. The package per person offered by the organizers is 265 EUR in single room and 188 EUR in double room.
Abstracts: The deadline for submitting the abstracts is September 15. Abstracts may be submitted in either Latex or MS Word compatible formats. The corresponding templates and other information can be checked here.
Young Scientists Forum: Young scientists willing to participate in the 2nd XLIC YSF should submit their abstract together with a short CV before September 15th, 2015.
See details here: https://xlic.qui.uam.es/?p=2154
Reimbursement: Invited speakers and MC members will be reimbursed for their travel and subsistenceexpenses in accordance to COST rules. Before incurring on any expense, please check COST Vademecum pages 19-23.
In particular, check the supporting documents you should keep in case you are travelling from/to the country where you are residing and keep all the local transport tickets.
Participants are kindly asked to keep their expenses as low as possible and ask only for the amounts they have spent, even if flat rates allow for a higher contribution, so the Action budget can be used to support more activities/participants. Thank you in advance!
STSM by Attila Toth, University of Debrecen (HU) with Benjamin Lasorne, Institut Charles Gerhardt Montpellier, Universite de Montpellier (FR)
On June 29th, 2015 (6 days)
From HUNGARY to FRANCE
Exploring the potential energy surfaces of NO2
In polyatomic molecules there are many energetically close-lying electronic states, which may cross at particular nuclear arrangements. In the vicinity of these degeneracy points, also known as conical intersections (CIs), the electronic and nuclear motions are strongly coupled, and nonadiabatic eects play a crucial role. Our long term goal is to provide a fully quantum mechanical treatment of such coupled electronic-nuclear dynamics induced by laser radiation in the NO2 molecule. For this reason, the purpose of the present STSM was the investigation of the involved potential energy surfaces.
First, we explored the number and nature of electronic states lying within the energy range of our interest. This scan was performed at the state-averaged complete active space self-consistent eld (SA-CASSCF) level of theory. The state averaging was performed over three states, employing correlation consistent polarized quadruple zeta (cc-pVQZ) basis set and an active space of 13 electrons in 10 orbitals. Based on these result, we decided to focus thereafter only on the calculation of the ground and rst excited state. Due to the CI between these two states (see Figure 1), the kinetic energy coupling diverges in the adiabatic representation, which makes the dynamical calculations numerically dicult. For this reason, an essential part of the present STSM was the diabatization of the PESs. This was achieved by a quasidiabatization procedure based on the linear vibronic coupling (LVC) model.
Figure 1: a) PES of the ground (1 2A1) and rst excited (1 2B2) electronic states of NO2. The black curve represents the seam of conical intersections. b) The three lowest lying PES of NO2 in C2v symmetry at Rs = 2.2 a.u.
The next step of our collaborative project will consist in the renement of the results ob-
tained during the STSM. This will be achieved by recomputing the PESs at the multireference conguration interaction (MRCI) level of theory. These surfaces will serve as input for our quantum dynamical calculations, which are expected to produce interesting results over the next few months.
Calculation of multi-channel ionization state properties in complex
The main purpose of the STSM, was to establish a benchmark for the scattering observables of neon. This would be very helpful to validate the new code, XCHEM, under development in the Fernando Martn’s group in Madrid, which is intended to describe the ionization continuum of complex atoms and molecules.
The comparisons consisted in three test cases: i) only one parent ion with 1s2 2s2 p6 cong-
uration (2s-1), ii) only one parent ion with 1s22s22p5 conguration (2p-1) and iii) both 2s-1 and 2p-1 parent ions. The energies obtained for these cations were in good agreement, and using our close-coupling approach, the eigenphases were obtained above and between the previous thresholds, which compared well with the reference.
The results obtained so far, contributed to the improvement of the XCHEM suite. At least one article will be prepared in the mid term, adding more correlated Ne neutral and cations, as well as a higher number of parent ions in the close-coupling expansion.
STSM by Samuel Jenkins, Royal Holloway University of London (UK) with Bernard Piraux, Université Catholique de Louvain (BE)
On June 15th, 2015 (13 days)
From UNITED KINGDOM to BELGIUM
Mixed basis set approach to ionization of atoms and molecules in strong fields
The Coulomb-Sturmian functions work extremely well when treating hydrogen in a strong laser field, but to treat other argon and other systems we propose a mixed basis to deal with the first few angular momenta where the potential is particularly non-hydrogenic and to use Sturmian functions for the angular momenta that remain.
Recently, in a collaboration between the group at Royal Holloway, the Bauer group in Poland and Professor Piraux’s group Louvain-la-Neuve, the excitation and ionization rates for the excited hydrogen atom were calculated using a Sturmian basis for all sub bound states pertaining to n = 2 when subject to a ten cycle, circularly polarized pulse with intensities ranging from 1011 – 1015 W/cm2 at a frequency of 800nm1. To compare with tunneling-type theories2, which predict the ratio of ionization rates for initially co-rotating and counter-rotating electrons, we are looking to extend the calculations performed on hydrogen with a circularly polarized pulse to argon from its ground state within the single active electron approximation. To do this, we propose to expand the first few angular momenta (up to and including l = 2) of the time dependent wavefunction as B-splines3 to cope with the non-hydrogenic potential, given here by Muller4, near the nucleus and the higher angular momenta as Coulomb-Sturmian functions. The mixed basis will produce sub-blocks of the Hamiltonian matrix with the laser interaction term involving both Sturmians and B-splines which will be dealt with numerically. The mixed basis will also result in a Hamiltonian with a bandwidth slightly larger than that of hydrogen. After the wavefunction has been propagated, ionization rates shall be calculated.
Thanks to the STSM, I was allowed to practice adapting Professor Piraux’s very successful Sturmian code by calculating the momentum maps for initially co-rotating and counter-rotating electrons in H to compare with results given in an earlier paper by Huens and Piraux5 (see Figures 1 and 2).
Figure 1: Photoelectron momentum distribution in the x-y plane for the ionization of a hydrogen atom in the excited state n = 2, l = 1, m = -1 subject to a 20 cycle circularly polarized laser pulse of frequency w = 0.25 (a.u.) and peak intensity I = 5.48351 x 1014 W/cm2 propagating along the z-axis.
Figure 2: Photoelectron momentum distribution in the x-y plane for the ionization of a hydrogen atom in the excited state n = 2, l = 1, m = 1 subject to a 20 cycle circularly polarized laser pulse of frequency w = 0.25 (a.u.) and peak intensity I = 5.48351 x 1014 W/cm2 propagating along the z-axis. Note the reduced probability to ionize relative to Figure 1.
STSM by Aurora Ponzi, University of Trieste (IT) with Nadja Doslic, Ruder Boškovic Institute (HR)
On June 2nd, 2015 (60 days)
From ITALY to CROATIA
Time resolved photoelectron spectroscopy as a probe for ultrafast excited state dynamics
This project aims at a high level theoretical description of Time-Resolved Photoelectron Spectroscopy (TRPES) observables obtained from pump-probe experiments. TRPES permits one to probe electronic states and nuclear dynamics with femtosecond time resolution. Our goal is the combination of photoionization observables calculation (using Dyson orbitals) with semiclassical non-adiabatic dynamics calculation. During this short term scientific mission, initial calculations have addressed photoionization from ground and excited electronic states of furan.
The development of a theoretical framework for simulating the ultrafast dynamics of complex molecular systems and computation of spectroscopic observables is a goal of current and general importance. We have performed a comparative study of photoionization observables computed using the Dyson orbitals as initial states and an accurate solution of the continuum one particle wavefunctions, at the DFT and TDDFT levels. The Dyson orbitals were computed at the CASSCF, ADC(2) and TDDFT levels.
The results obtained during this mission will be collected in a manuscript in preparation. This preliminary study constitutes the first step of a more ambitious project which joins the know-how of two theoretical groups.
In parallel with the main project, I also performed multireference quantum chemistry calculations for two systems: pyrrole and adenine-water. The results of my contribution are included in an already published paper (Phys. Chem. Chem. Phys. 2015, 17,19012) and in a recently submitted paper to J. Phys. Chem. A.
STSM by Philipp Marquetand, University of Vienna (AT) with Tamas Rozgonyi, Hungarian Academy of Sciences (HU)
On July 2nd, 2015 (8 days)
From AUSTRIA to HUNGARY
Strong-Field Ionization Simulations Using Adiabatic Elimination
Strong-field ionization including multiphoton transitions is hardly understood yet due to the complex interplay of intermediate resonant states, their dynamic Stark shift, the ponderomotive potential and many more fundamental processes. In order to obtain nonetheless a simple and more intuitive picture, we have developed a theoretical description and a corresponding code, which makes use of two main approximations. All off-resonant intermediate states are not treated explicitly but removed by adiabatic elimination (ADEL) from the system of equations of motion. Furthermore, the ionization continuum is represented by a Legendre-polynomial based discretization approach.
In this STSM, we extended our code to include non-adiabatic coupling between multiple intermediate resonant states. In this way, we are able to test a hypothesis developed by our experimental partner, Thomas Weinacht (Stony Brook University), that such vibrational couplings are at the origin of some of the peaks in the photo-electron spectrum of Iodobromomethane. We have tested our new implementations, comparing a 0-dimensional, a 1-dimensional and our new 1-dimensional code with couplings. First simulations on a model with arbitrarily chosen parameters show that indeed non-adiabatic couplings can lead to additional peaks in the photo-electron spectrum, see Fig. 1. The model consists of a ground state |0>, two intermediate resonant states |i1>, |i2> and two electronic continua |c1>, |c2>. The states |0> and |i1> are coupled via a 5-photon process, while the states |i1> and |c1> as well as |i2> and |c2> are coupled via a 2-photon process, respectively. A non-adiabatic coupling between |i1> and |i2> can be switched on and off. If the coupling is present, an additional peak appears in the photo-electron spectrum.
STSM by Sylvain Maclot, Lund University (SE) with Alicia Palacios, Universidad Autónoma de Madrid (ES)
On June 28th, 2015 (7 days)
From SWEDEN to SPAIN
Setting up collaboration towards ultrafast molecular dynamics using XUV-XUV pump-probe techniques
The relaxation dynamics of an ionized/excited molecular system leads to different fundamental processes occurring at sub-femtosecond timescales as electron dynamics, charge transfer/migration and nuclear motion. Time-resolved XUV-XUV pump-probe experiments should allow deeper insight to the key roles of these processes. Such studies should be feasible soon at the high-intensity high-order harmonic generation beamline of Lund Laser Centre. Main part of the time, the results of these kinds of experiments are quite complicated to interpret and require theoretical support. The team of Fernando Martin, managed by Alicia Palacios, has already started to develop theoretical tools based on time-dependent ab initio methods to account for the full dimensionality of the problem. The main purpose of this application was to start up collaboration between theoreticians from Madrid and experimentalists from Lund in order to prepare the future experiments/calculations and results whose can be done together.
We evaluated the suitability of our existing tools, both experimental and theoretical sides, to apply XUV-XUV pump-probe schemes in different contexts (atoms, small and large molecules; single or double ionization processes; excitation processes). Then we discussed the type of calculations and models that can be perform in a short-term period for different problems, and the details about the beamline and experimental set-up. For instance, investigated the effect of attosecond pulse train (APT) compared to single attosecond pulse (SAP) (figure).
During this mission, we have limited the targets and processes that we can tackle both experimentally and theoretically and we have carried out a scientific exchange specifying the physical parameters and the observables that can be measured/computed considering existing tools and their current limitations, as well as methodologies than could be developed in a near future. Now, we have common working bases to plan our future and specific tasks.
STSM by Lucas SCHWOB, CIMAP, Caen (FR) with Thomas Schlathölter, University of Groningen (NL)
On June 2nd, 2015 (7 days)
From FRANCE to NETHERLANDS
Photostability of superhydrogenated nitrogen-subsituted polycyclic aromatic hydrocarbons
Polycyclic Aromatic Hydrocarbons (PAHs) are of great interest in astrophysics and astrochemistry fields because of their presence in interstellar gas clouds. In this particular environment, PAHs undergo irradiation of photons with energies ranging from UV to X-ray. Moreover, the existence of highly hydrogenated PAH in the interstellar medium could potentially lead to the formation of H2, the most abundant molecule in the universe. During this STSM we studied the photoionization and fragmentation of coronene and hydrogenated coronene under VUV photon irradiation.
Experiments were performed at the BESSY II synchrotron in Berlin, using a home-made tandem mass spectrometer. A Slevin-type hydrogen discharge source has been used to attach single H atoms to coronene radical cations produced by electrospray ionization. Photon irradiation occurred in a 3D RF-Paul trap, and cationic fragments were analyzed by time-of-flight mass spectrometry. Photofragmentation spectra were recorded for VUV photon energies ranging from 10 to 25eV. For coronene and coronene+H, we observed, as shown in figure 2, a strong yield of 2H or H2 loss from both dication by photoionization, whereas losses of 2nH or n(H2) with n < 5 were observed after absorption of one photon of 284-300eV (C 1s-edge electron removal). Unlike soft-Xray, no deexcitation through H+ loss from the dication was observed after absorption of a single VUV photon.
The spectra obtained are still under analysis and will lead to the publication of a new manuscript with original results. Moreover, this STSM has initiated a new collaboration between our two groups. A new research proposal for beamtime at the BESSY II synchrotron, has already been submitted and accepted. This will allow us to study human type II collagen peptides upon VUV and soft X-ray irradiation.
Figure 2 : Mass spectrum of protonated coronene after the absorption of one 17.25eV photon.
STSM by Katrin Tanzer, University of Innsbruck (AT) with Edwin Kukk, University of Turku (FI)
On April 27th, 2015 (26 days)
From AUSTRIA to FINLAND
Photo-Ionization of Nitroimidazolic Compounds
During this Short Term Scientific Mission two nitroimidazolic derivatives, 4-nitroimidazole (4NI) and 1-methyl-5-nitroimidazole (Me5NI), were studied. These compounds have been proposed as radiosensitizers and have shown very interesting effects in their fragmentation patterns upon low energy electron attachment. To study the response of these molecules towards ionizing radiation, experiments with UV radiation and soft X-rays were undertaken.
Of special interest for us are the results of our PEPIPICO (Photoelectron-Photoion-Photoion Coincidence) study following C 1s core ionization of 4NI and Me5NI since this process is highly relevant for the study of high energy (keV range, cf. medical X-rays) radiation absorption. We obtained PIPICO maps by recording the flight times of two correlated ions from which the most dominant fragmentation pathways upon photoionization can be determined. The PEPIPICO maps of 4NI and Me5NI exhibit significant differences, albeit their similar structures (Figure 1). While in the case of 4NI most fragmentation patterns show a coincidence with the ionized nitro group (NO2+; 46 amu), NO+ (30 amu), or O+ (16 amu), these cations can hardly be observed for Me5NI, where the fragmentation is thought to be proceeded via loss of the neutral nitro group and sequential loss of the ionized methyl group (CH3+; 15 amu), which leads to subsequent cleavage of the ring.
Future collaborations between the Institute for Ion Physics and Applied Physics have been discussed during the STSM. It is planned to compile two publications from this STSM – one concerning the C 1s core ionization of 4NI and Me5NI that is presented in this report and one discussing the fragmentation pattern obtained by PEPIPICO measurements upon valence ionization. Furthermore, the possibility of more scientific exchanges in the future has been discussed.
Figure 1: PEPIPICO maps of 4-nitroimidazole (left) and 1-methyl-5-nitroimidazole (right). The axes show the flight times of the slower and the faster ion, respectively and the numbers signify the mass of the ionic fragments.
 M.R. Horsman & A.J. van der Kogel. In: Joiner & van der Kogel, Basic Clinical Radiobiology, Hodder Arnold, 2009
 K. Tanzer et al. Angew. Chem. Int. Ed., 2014, 53, 12240-12243
 K. Tanzer et al. J. Phys. Chem. A. 2015, Just Accepted Manuscript. DOI: 10.1021/acs.jpca.5b02721