Welcome on My Personal webpage !

Presentation

"I am a physicist who has a specific attraction for complex problems which require an experimental point of view to get new insights. This allows me to bring challenge and fun together!"

My impulse for research started during the graduation of my Bachelor's degree and Master'degree in "Science de la Matière" at the École Normale Supérieure of Lyon (France) from 2009 to 2012. Then this momentum continued during my PhD which I obtained from the University of Lyon in October 2016.

My PhD work, entitled "Femtosecond and sub-femtosecond electron dynamics in super-excited complex molecular systems" was performed at the Institut Lumière Matière in the group Structure & Multi-Scales Dynamics of Complex Molecules under the supervision of Dr. Franck Lépine and Dr. Christian Bordas.
It mostly consisted in studying the multielectronic effects and non-adiabatic mechanisms in highly excited large molecules in gas phase. Thus, I built an entire XUV-pump and IR-probe optical setup coupled to a Velocity Map Imaging spectrometer enabling to measure the transient ion yield and electron momentum distribution from sevral species such as atoms/small molecules (e.g. He, Ar, N₂) or carboneous molecules (e.g. PAH, C₆₀) and biomolecules (e.g. cafeine, DNA basis).
During my PhD I could obtain expertise in time-resolved ultrafast spectroscopy, out-of-equilibrium molecular physics, femtosecond amplified laser, high harmonic generation, attosecond science, electron/ion detection and vacuum chamber desing for gas phase experiments.

Then, I decided to move toward the condensed matter field in order to expand my general knowledge about ultrafast dynamics in the many-bodies quantum systems but also to start bridging the concepts of molecular physics with the one of condensed matter. Thus, in December 2016, I started a post-doctorate at the University of Trieste (Italy) in the group of Prof. Daniele Fausti (on the INCEPT project), whose laboratories are located in the synchrotron/FEL facility Elettra Sincrotrone S.C.P.A./FERMI in Trieste.
The aim of this post-doc research was to study out-of-equilibrium strongly correlated materials and to show how to control their quantum matter phases and their electronic properties through excitation of their low energy degrees of freedom. Moreover, we were developing a full quantum state reconstruction of light pulses interacting with the out-of-equilibrium matter phases by measuring beyond the photon number mean value, i.e. its fluctuations and spectral phase. This new approach should provide richer statistical information than standard time-resolved spectroscopy techniques.
During my first post-doctorate experience, I could gain complementary expertise in strongly correlated materials (cuprates, HTSC), mid-IR pulsed sources (OPA, DFG), quantum optics, cryostat engineering.

In 2019, I joined the ERC-Synergy project Nanocosmos, co-supervised by Dr. Christine Joblin (group Milieu Interstellaire, Cycle de la Matière, Astro-Chimie), at the Institut de Recherche en Astrophysique et Planétologie (Toulouse, France), in order to study the photochemistry of PAH clusters under VUV irradation in link with their evolution in the photodissociation regions.

Finally, in 2021, I got a CNRS researcher position at LCAR in the CLUSTER team. My current project aims in studying experimentally the photo-induced processes in gas-cluster interactions which are relevant for astrochemistry. This work will be performed on the new setup PIRENEA 2 that has been developped thanks to the Nanocosmos ERC. We will combine state-of-the-art techniques such as atomic and molecular cluster sources, cryogenic ion trapping, high resolution mass spectrometry and several spectroscopy schemes (MidIR, NIR, UV, VUV, two-photons etc...) in order to investigate gas-cluster-light interactions.

News

04-Jul-2024 : JCJC ANR Project CASSOULExp is accepted

Abstract: Cosmic dust plays a crucial role in the physical and chemical evolution of the interstellar medium. It exists an abundant population of nanometer size grains (named nanograins) which have a high surface over volume ratio. These nanograins are expected to be strongly coupled to the gas phase and to contribute to its chemical enrichment. Up to now, gas-grain interactions have been studied by using “infinite” surfaces and therefore cannot account for size and morphology effects specifics to these nanograins. The CASSOULExp project aims to study cationic clusters composed of polycyclic aromatic hydrocarbons and water molecules as a model case of interactions between water molecules and carbonaceous nanograins expected to exist in planet and star forming regions. In order to characterize these systems, we will develop a methodology able to systematically measure the infrared spectral signatures of these clusters as a function of the nature and the number of molecules that composed them. Moreover, we will study the modifications of these spectra as a function of the cluster temperature in order to explore desorption and molecular diffusion mechanisms. We will be carrying out this project using PIRENEA 2, a unique setup in laboratory astrophysics, which will enable to produce these clusters, thermalize them, isolate them under astrophysical conditions and measure their action spectrum in the infrared. These new data will allow us to propose families of nanograins organized according to the observed spectral trends with respect to the experimental parameters. This will be of high interest to constraint quantum chemistry models and these results will be useful to interpret astrophysical observations, notably those performed by the James Webb Space Telescope. This project will open the path to more complex studies regarding other spectral or temporal domains performed on molecular or atomic clusters which have a high interest in astrochemistry or atmospheric chemistry.

CASSOULExp: ChAracterizating the Spectral Signatures of astrO-relevant carbonaceoUs cLusters Experimentally.
PI : A. Marciniak
Project members : F. Baterdouk, S. Zamith, C. Joblin, A. Bonnamy, A. Simon, M. Rappacioli, P. Moretto-Capelle, J.-M. L’Hermite

15-Jan-2024 : Article published in PCCP

Abstract: Protonated mixed pyrene–water clusters, (Py)m(H2O)nH+, where m = [1–3] and n = [1–10], are generated using a cryogenic molecular cluster source. Subsequently, the mass-selected mixed clusters undergo controlled collisions with rare gases, and the resulting fragmentation mass spectra are meticulously analyzed to discern distinct fragmentation channels. Notably, protonated water cluster fragments emerge for n ≥ 3, whereas they are absent for n = 1 and 2. The experimental results are complemented by theoretical calculations of structures and energetics for (Py)(H2O)nH+ with n = [1–4]. These calculations reveal a shift in proton localization, transitioning from the pyrene molecule for n = 1 and 2 to water molecules for n ≥ 3. The results support a formation scenario wherein water molecules attach to protonated pyrene PyH+ seeds, and, by extension, to (Py)2H+ and (Py)3H+ seeds. Various isomers are identified, corresponding to potential protonation sites on the pyrene molecule. Protonated polycyclic aromatic hydrocarbons are likely to be formed in cold, dense interstellar clouds and protoplanetary disks due to the high proton affinity of these species. Our findings show that the presence of protonated PAHs in these environments could lead to the formation of water clusters and mixed carbon–water nanograins, having a potential impact on the water cycle in regions of planet formation.

Diversity of protonated mixed pyrene–water clusters investigated by collision induced dissociation.
A. M. Nair, H. Leboucher, L. Toucouere, S. Zamith, C. Joblin, J.-M. L’Hermite, A. Marciniak and A. Simon

11-Aug-2022 : Article published in JPCA

Abstract: Polycyclic aromatic hydrocarbons are major species in astrophysical environments, and this motivates their study in samples of astrochemical interest such as meteorites and laboratory analogues of stardust. Molecular analyses of carbonaceous matter in these samples show a dominant peak at m/z = 202.078 corresponding to C16H10. Obtaining information on the associated isomeric structures is a challenge for the molecular analysis of samples available in very small quantities (mg or less). Here we show that coupling laser desorption ionization mass spectrometry with ion trapping opens up the possibility of unraveling isomers by activating ion fragmentation via collisions or photon absorption. We report the best criteria for differentiating isomers with comparable dissociation energies, namely pyrene, fluoranthene, and 9-ethynylphenanthrene, on the basis of the parent dissociation curve and the ratio of dehydrogenation channels. Photoabsorption schemes (multiple photon absorption in the visible range and single photon absorption at 10.5 eV) are more effective in differentiating these isomers than activation by low energy collisions. The impact of the activation scheme on the fragmentation kinetics and dehydrogenation pathways is discussed. By analyzing the 10.5 eV photodissociation measurements with a simple kinetic model, we were able to derive a branching ratio for the H and 2H/H2 loss channels of the parent ions. The results suggest a role in the formation of H2 for bay hydrogens that are present in both fluoranthene and 9-ethynylphenanthrene. In addition, we suggest for the latter the presence of a highly competitive 2H loss channel, possibly associated with the formation of a pentagonal ring.

Isomer Differentiation of Trapped C₁₆H₁₀⁺ Using Low-Energy Collisions and Visible/VUV Photons.
V. Vinitha, V. R. Mundlapati, A. Marciniak, M. Carlos, H. Sabbah, A. Bonnamy, L. Noguès, D. Murat, O. Coeur-Joly, and C. Joblin,

18-Oct-2021 : Article published in PRX

Abstract: Unraveling ultrafast molecular processes initiated by energetic radiation provides direct information on the chemical evolution under extreme conditions. A prominent example is interstellar media where complex molecules such as polycyclic aromatic hydrocarbons (PAHs) are excited by energetic photons. Until recently, ultrafast dynamics following such excitations remained largely unexplored due to the lack of relevant technologies. Here, we use time-resolved mass spectrometry combining ultrashort femtosecond XUV and IR pulses, to investigate the dynamics induced by high-energy photon excitation in PAHs. We demonstrate that excited cations relax through a progressive loss of vibrational selectivity, created at the early-stage dynamics, and which represents the first steps of a complete intramolecular vibrational energy redistribution. This process is in competition with the recently revealed correlation-band dynamics. These results might have direct consequences for the development of XUV molecular physics and other fields such as astrochemistry.

Ultrafast Vibrational Relaxation Dynamics in XUV-Excited Polycyclic Aromatic Hydrocarbon Molecules
A. Boyer, M. Hervé, V. Despré, P. Castellanos Nash, V. Loriot, A. Marciniak, A.G.G.M. Tielens, A.I. Kuleff, and F. Lépine

01-Oct-2021 : Permanent Researcher position at LCAR

After few years of application at the CNRS competitive national exam, I finally succeeded and I joined the CNRS as a permanent researcher at LCAR. This is the beginning of a long adventure with many interesting things to discover, many people to meet and many experiments to play with.... and above all without any end!

06-Aug-2021 : Article published in A&A

Abstract: The interaction of polycyclic aromatic hydrocarbons (PAHs) with vacuum ultraviolet (VUV) photons triggers the emission of the well-known aromatic infrared bands (AIBs), but other mechanisms, such as fragmentation, can be involved in this interaction. Fragmentation leads to selection effects that favor specific sizes and structures. Our aim was to investigate the impact of aliphatic bonds on the VUV photostability of PAH cations in a cryogenic and collisionless environment with conditions applicable for photodissociation regions (PDRs). Aliphatic PAH derivatives are found to have a higher fragmentation rate and a higher carbon to hydrogen loss compared to regular PAHs but some of their photoinduced fragments with peripheral pentagonal cycles, can be as stable as, or even more stable than, the bare PAH cations. The most stable species for which there is an effective competition of fragmentation with isomerization and radiative cooling are identified, providing clues on the structures favored in PDRs. This work supports a scenario in which the evaporation of nanograins with a mixed aliphatic and aromatic composition followed by VUV photoprocessing results in both the production of the carriers of the 3.4 um AIB by methyl sidegroups and in an abundant source of small hydrocarbons at the border of PDRs. An additional side effect is the efficient formation of stable PAHs that contain some peripheral pentagonal rings. Our experiments also support the role of isomerization processes in PAH photofragmentation, including the H-migration process, which could lead to an additional contribution to the 3.4 um AIB.

Photodissociation of aliphatic PAH derivatives under relevant astrophysical conditions
A. Marciniak, C. Joblin, G. Mulas, V. Rao Mundlapati, and A. Bonnamy

04-Jan-2021 : Article published in Nature Physics

Abstract: Addressing the role of quantum coherence in the interplay between the different matter constituents (electrons, phonons and spin) is a critical step towards understanding transition metal oxides and design complex materials with new functionalities. Here we use coherent vibrational control of onsite d-d electronic transitions in a model edge-sharing insulating transition metal oxide (CuGeO3) to single-out the effects of vibrational coherence in electron-phonon coupling. By comparing time domain experiments based on high and low frequency ultrashort pumps with a fully quantum description of phonon assisted absorption, we could distinguish the processes associated to incoherent thermal lattice fluctuations from those driven by the coherent motion of the atoms. In particular, while thermal fluctuation of the phonon bath uniformly increases the electronic absorption, the resonant excitation of phonon modes results also in light-induced transparency which is coherently controlled by the vibrational motion.

Vibrational coherent control of localized d-d electronic excitation
A. Marciniak, S. Marcantoni, F. Giusti, F. Glerean, G. Sparapassi, T. Nova, A. Cartella, S. Latini, F. Valiera, A. Rubio, J. van den Brink, F. Benatti, and D. Fausti

08-Jul-2020 : Article published in Review of Scientific Instruments

Abstract: We report here an experimental setup to perform three-pulse pump–probe measurements over a wide wavelength and temperature range. By combining two pump pulses in the visible (650 nm–900 nm) and mid-IR (5 μm–20 μm) range, with a broadband supercontinuum white-light probe, our apparatus enables both the combined selective excitation of different material degrees of freedom and a full time-dependent reconstruction of the non-equilibrium dielectric function of the sample. We describe here the optical setup, the cryogenic sample environment, and the custom-made acquisition electronics capable of referenced single-pulse detection of broadband spectra at the maximum repetition rate of 50 kHz, achieving a sensitivity of the order of 10−4 over an integration time of 1 s. We demonstrate the performance of the setup by reporting data on a mid-IR pump, optical push, and broadband probe in a single crystal of Bi2Sr2Y0.08Ca0.92Cu2O8+δ across the superconducting and pseudogap phases.

Visible pump–mid infrared pump–broadband probe: Development and characterization of a three-pulse setup for single-shot ultrafast spectroscopy at 50 kHz
A. Montanaro, F. Giusti, M. Colja, G. Brajnik, A. Marciniak, R. Sergo, D. De Angelis, F. Glerean, G. Sparapassi, G. Jarc, S. Carracto, G. Cautero and D. Fausti.

19-Jun-2020 : Article published in Optics Letters

Abstract: Unveiling and controlling the time evolution of the momentum and position of low energy excitations such as phonons, magnons, and electronic excitation is the key to attain coherently driven new functionalities of materials. Here we report the implementation of femtosecond time- and frequency-resolved multimode heterodyne detection and show that it allows for independent measurement of the time evolution of the position and momentum of the atoms in coherent vibrational states in 𝛼-quartz. The time dependence of the probe field quadratures reveals that their amplitude is maximally changed when the atoms have maximum momentum, while their phase encodes a different information and evolves proportionally to the instantaneous atomic positon. We stress that this methodology, providing the mean to map both momentum and position in one optical observable, may be of relevance for both quantum information technologies and time-domain studies on complex materials.

Time-resolved multimode heterodyne detection for dissecting coherent states of matter
F. Glerean, G. Jarc, A. Marciniak, F. Giusti, G. Sparapassi, A. Montanaro, E. Maria Rigoni, J. Owen Tollerud, and D. Fausti.

31-Mar-2020 : Article published in Journal of Physics: Photonics

Abstract: We have investigated photoionization delays in N₂ by combining an extreme ultraviolet (XUV) attosecond pulse train generated by high harmonic generation (HHG) and a second harmonic femtosecond pulse with angularly resolved photoelectron spectroscopy. While photoionization delay measurements are usually performed by using a standard XUV-infrared scheme, here we show that the present approach allows us to separate electronic states that otherwise would overlap, thus avoiding the spectral congestion found in most molecules. We have found a relative delay between the X and A ionic molecular states as a function of the photon energy of up to 40 attoseconds, which is due to the presence of a shape resonance in the X channel. This approach can be applied to other small quantum systems with few active electronic states.

High harmonic generation-2ω attosecond stereo-photoionization interferometry in N₂
V. Loriot, A. Marciniak, S. Nandi, G. Karras, M. Hervé, E. Constant, E. Plésiat, A. Palacios, F. Martín and F. Lépine

01-Oct-2019 : New Post-doc started at IRAP

Start of my new post-doc position at the IRAP in the MICMAC group in collaboration with Christine Joblin. I will experimentally study the photochemistry of nanograins in the interstellar condition.

15-Feb-2019 : Article published in Physical Review Letters

Abstract: One of the possible outcomes of time resolved techniques is the capability to control and, eventually, induce material properties on short (on the order of picoseconds or less) timescales through light pulses. In this kind of experiments, a sample is perturbed suddenly by an ultrashort intense light pulse and then its effect on the material is studied as a function of the time passed from the excitation. A good sample candidate to reach our scope is represented by cuprates, a class of materials characterized by Copper-Oxygen layers which determine their peculiar properties. In particular, their rich phase diagram suggests that it is possible to reach a number of matter phases just by changing some parameters. For example, below the so-called critical temperature our sample enters a superconducting phase. In our work we observed that light pulses with certain properties (in particular regarding energy and polarization) can induce, for a very short time interval (1-2 ps) a superconducting response even above the critical temperature. Experimental data are accompanied by a theoretical effective model, which justifies the enhancement of the superconducting response with an increase of coherence in the material. The hypothesis opens the possibility to change the thermodynamic constraints and to make quantum coherence feasible even at relatively high temperatures.

Evidence of enhanced coherence in the superconducting state of optimally doped Bi₂Sr₂Y_0.08Ca_0.92Cu₂O_8+δ by midinfrared pulse excitation
F. Giusti, A. Marciniak, F. Randi, G. Sparapassi, F. Boschini, H. Eisaki, M. Greven, A. Damascelli, A. Avella, and D. Fausti.

18-Jan-2019 : Article published in Nature Communications

Abstract: The many-body quantum nature of molecules determines their static and dynamic properties, but remains the main obstacle in their accurate description. Ultrashort extreme ultraviolet pulses offer a means to reveal molecular dynamics at ultrashort timescales. Here, we report the use of time-resolved electron-momentum imaging combined with extreme ultraviolet attosecond pulses to study highly excited organic molecules. We measure relaxation timescales that increase with the state energy. High-level quantum calculations show these dynamics are intrinsic to the time-dependent many-body molecular wavefunction, in which multi-electronic and non-Born−Oppenheimer effects are fully entangled. Hints of coherent vibronic dynamics, which persist despite the molecular complexity and high-energy excitation, are also observed. These results offer opportunities to understand the molecular dynamics of highly excited species involved in radiation damage and astrochemistry, and the role of quantum mechanical effects in these contexts.

This is a study following the one of my first Nature Communication dealing with XUV induced dynamics in naphtalene but observed on the part of the slow two-color electrons
The story is still continuing in Lyon and that's great!

Electron correlation driven non-adiabatic relaxation in molecules excited by an ultrashort extreme ultraviolet pulse
A. Marciniak, V. Despré, V. Loriot, G. Karras, M. Hervé, L. Quintard, F. Catoire, C. Joblin, E. Constant, A. I. Kuleff & F. Lépine.

16-Nov-2018 : Article published in Journal of Physical Chemistry Letters

Abstract: Ultrafast XUV chemistry is offering new opportunities to decipher the complex dynamics taking place in highly excited molecular states and thus better understand fundamental natural phenomena as molecule formation in interstellar media. We used ultrashort XUV light pulses to perform XUV pump–IR probe experiments in caffeine as a model of prebiotic molecule. We observed a 40 fs decay of excited cationic states. Guided by quantum calculations, this time scale is interpreted in terms of a nonadiabatic cascade through a large number of highly correlated states. This shows that the correlation driven nonadiabatic relaxation seems to be a general process for highly excited states, which might impact our understanding of molecular processing in interstellar media.

Finally, 5 years after having performed the experiments in Milano, this nice study dealing with XUV induced dynamics in cafeine has been published.
Cafeine is good !

Ultrafast nonadiabatic cascade and subsequent photofragmentation of XUV excited caffeine molecule.
A. Marciniak, K. Yamazaki, S. Maeda, M. Reduzzi, V. Despré, M. Hervé, M. Meziane, T. A. Niehaus, V. Loriot, A. I. Kuleff, B. Schindler, I. Compagnon, G. Sansone, and F. Lépine.

Contact

Dr. Alexandre MARCINIAK
Laboratoire Collisions Agrégats Réactivité - UMR5589
Université Paul Sabatier - Bat. 3R4
118 route de Narbonne
31062 Toulouse Cedex 09, France

Phone icon Office: +33 (0)5 61 55 74 59
Lab: +33 (0)5 61 55 61 85 or +33 (0)5 61 55 76 73

alexandre.marciniak [at] irsamc.ups-tlse.fr

Alexandre Marciniak

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Welcome on My Personal webpage !

Presentation

"I am a physicist who has a specific attraction for complex problems which require an experimental point of view to get new insights. This allows me to bring challenge and fun together!"

News

Contact