EDMs, i.e. electric dipole moments of electrons, neutrons or nuclei are sensitive probes for new physics beyond the Standard Model of particle physics. In the present project, we propose to measure the EDM of those systems embedded in a cryogenic solid matrix of inert gas or hydrogen. Matrices offer unprecedented sample sizes while maintaining characteristics of an atomic physics experiment, such as the possibility of manipulation by lasers. An EDM experiment on molecules in inert gas matrices has the potential to reach a statistical sensitivity of the order of 1e–36 e cm; a value beyond that of any other proposed technique. With this project, in a strong collaboration between experimental (LAC, ISMO,LPL) and theoretical (CIMAP) groups, we first aim at performing a detailed investigation of all limiting effects (mainly the ones limiting the optical pumping performance and coherence time) using Cs atoms. This should provide a first proof of principle EDM measurement and set the ground for precise study of systematic effects which will allow EDMMA to reach unprecedented precision

The Electrophylle project seeks to characterize a fundamental process involved in the initial transformation of light energy in the reaction center of Photosystem II that initiates photosynthesis in plants and algae. Electrophylle will create a synergy around a new gas phase experimental method applied to chlorophyll systems, a condensed phase approach and their theoretical modeling. Photosystem II (PSII) plays a central role during photosynthesis: indeed, solar energy collected by the antennae is transferred to PSII where the initial charge separation takes place, leading after subsequent steps to a negative charge production and water splitting into dioxygen+ protons. This charge separation is the initial and limiting step to the production of energy and dioxygen, the sources of life. Its quantum efficiency is close to unity and remains unexplained unless one accepts an hypothesis involving a resonant effect and is produced by natural evolutive adaptation. Indeed, the core of the PSII reaction center consists of a set of 12 chlorophyll-related molecules undergoing excitonic coupling, which can be reduced to a working ensemble of only 4 molecules. 2D time-domain spectroscopy measurements indicate the crucial influence in the efficiency of the charge separation mechanism, of resonances between chlorophyll vibration frequencies and the energy gaps separating neutral from ionic pairs. The resulting model reproduces the initial charge separation dynamics in this reaction center based however on fragmentary spectroscopic data. The electronic and vibrational structure of the elements in the core of the PSII reaction center, the chlorophylls, their excitonic pairs are insufficiently known to validate the essential hypothesis of a vibration energy gap resonance that will establish a new model. This can only be achieved by measurements in the gas phase or cryogenic solutions or as in the Electrophylle project, by a combination of both with quantum chemistry calculations. We propose to determine by resonant electron photodetachment spectroscopy, the vibrational and electronic structure of neutral chlorophyll and chlorophyll dimers cooled at 10K and electron tagged. Gas phase spectroscopy of biomolecules has the unique advantage of allowing access to the structure of biomolecules in the absence of medium interactions and being directly comparable to the results of quantum computations. On the other hand, we will achieve microsolvation of chlorophylls by single molecular bonds to bring them into dimers akin to those of the reaction center. This step is essential since it allows tuning their electronic levels into resonance with chlorophyll vibrations that drive charge separation with maximum efficiency. These gas phase measurements will be combined with fluorescence line narrowing (FLN) spectroscopy that addresses the interacting dimers in the protein environment. This will give access to a complete picture of the interaction landscape in chlorophyll dimers in several conditions, from free to assembled into special pairs. Specific quantum calculations will characterize the electronic and vibrational structure of these systems. This will yield energy level positions for chlorophylls and pairs in ground and first electronically excited states, together with a landscape of the interactions within chlorophyll pairs between neutral and ionic states. This project is designed to characterize a fundamental process related to energy transformation –photosynthesis- by a synergy between a new experimental method as applied to a complex system, the reaction center of Photosytem II, theoretical modelling and condensed phase spectroscopy. The precise modeling and understanding of such a fundamental process could help boosting the efficiency of artificial molecular photocatalysts, the electronic properties of which could be tuned to improve their ability of performing ultrafast (10-12 s) charge separation with high quantum yield.

The PRIMA project is devoted to the experimental characterization of relaxation processes resulting from the absorption of Vacuum Ultra-Violet (VUV) radiations by gaseous molecules present in astrophysical media such as the interstellar medium, planetary atmospheres and comets. The proposed experiments in this project will be performed at Institut des Sciences Moléculaires d’Orsay (ISMO) and on the DESIRS beamline of SOLEIL synchrotron. These experimental facilities will provide us with the required tools to carry out the complete overview studies of the targeted molecular and radical species. A special attention will be paid to the characterization of carbon- and nitrogen-bearing radicals for which only scarce information are available. Emphasis will be given to (azo)-carbonated molecules and to ammonia (NH3) in order to retrieve new and reliable data for the astrophysics/astrochemistry community. Quantitative data such as photodissociation branching ratios and absolute photoionization or photoabsorption cross sections will be measured for the first time. These results and the spectral analysis will be supported by theory in collaboration with theoreticians from ISMO and ULB (Belgium). The financial support requested in this application will allow us to build the first pulsed high-resolution and broadly-tunable VUV laser source in France. This system will be the master piece of the experimental setup needed for the planned absolute measurements described above. The complementarity of this new VUV source with the ones already available in the “plateau de Saclay” environment (DESIRS beamline of SOLEIL, CLUPS laser center) will strengthen the position of Paris-Saclay University as a world leader in the field of molecular VUV spectroscopy and photodynamics.

In order to explain specific infrared (IR) emission bands observed in the interstellar medium (ISM), and often referred to as the aromatic infrared bands (AIBs), the presence of polycyclic aromatic hydrocarbons (PAHs) was suggested about 30 years ago. The AIB carriers are also suspected to strongly contribute to the broad absorption feature known as the ultraviolet (UV) bump present in the interstellar extinction curve. Despite a large number of experimental and theoretical studies, the exact nature of the AIB carriers has remained elusive. Most previous experimental and theoretical studies focused on the electronic and vibrational spectroscopy of a limited set of relatively small and planar PAHs. The PACHYNO project is dedicated to the study of isolated carbon/hydrogen-based nanoparticles in the size domain of 20 to 200 atoms as potential AIB carriers. The project relies on the best use of state-of-the-art computational and experimental approaches and their synergy, without any a priori selection of molecular species. Experimentally, astrophysical analogues will be produced using a low-pressure flame resulting in a distribution of carbon/hydrogen nanoparticles from which spectroscopic signatures will be measured. In the theoretical part, a systematic and automatic exploration of molecular structures and their spectroscopic responses will be investigated. The large variety of nanostructures arising from the rich allotropy of carbon and the presence of hydrogen will be computationally explored by means of atomistic simulations using an approach combining the AIREBO reactive force field and the density-functional theory-based tight-binding (DFTB) approach. The diversity of hydrocarbons will be explored by varying the size of the nanostructures, the relative amounts of carbon and hydrogen, and external parameters such as temperature. Systematic characterization will be achieved by mapping these structures with order parameters that account for the different aspects of structural organization and chemical bonding. New order parameters derived from cluster physics will be developed to describe the carbonaceous nanoparticles. Using DFTB and time-dependent DFTB, spectroscopic properties of the simulated nanoparticles will be quantified from the IR to the UV wavelengths in connection with experimental and astronomical data. The simulations will be performed over a large statistical sampling. The joint characterization of the hydrocarbon nanostructures in terms of structural, chemical, and spectroscopic signatures will be rationalized by mapping out the relevant correlations between these different properties. Our ambition is to provide some general rules allowing spectral features to be related to structural and chemical properties such as size, C/H ratio or via the order parameters. Experimental measurements of IR emission and electronic UV-visible electronic spectra will be performed using an existing experimental setup developed at ISMO. Large hydrocarbon compounds of up to few nanometers will be generated using a low-pressure flame that can produce well-controlled and reproducible distributions of species. Comparison between experimental and theoretical results will give information about the structural organization of the nanoparticles under various experimental conditions. Finally, comparison with astrophysical spectra will advance our understanding of interstellar carbonaceous matter and provide a solid background to improve dust models in astrophysics. Such progress will contribute to the scientific impact of future space missions such as the James Webb Space Telescope (JWST) to be launched in 2018.

Superconductivity is a fascinating quantum state of condensed matter. Its study and understanding have always aroused immense interest in fundamental physics, but also in materials science and its exploitation leads to numerous technological applications: lossless current transport, energy storage, quantum computation or sensors with unprecedented resolution. In 1986, the discovery of high Tc superconductivity in cuprates allowed the acceleration of enormous progress, both experimentally and theoretically, in several areas of condensed matter physics. However, the origin of high Tc superconductivity is still an unresolved problem; One of the main reasons is the complexity of the physics of cuprates resulting from multiple interactions in competitions (magnetic fluctuations, strong electronic correlations, charge-network coupling, etc.) and nearby orders (charge density wave, antiferromagnetism, pseudo-gap, etc.). The emergence of superconductivity in nickelates, structural and electronic “cousins” of cuprates, was eagerly awaited, but only postponed in 2018 in LaNiO3 / (La, Sr) MnO3 superlattices and in August 2019 in thin layers of the “Infinite phase” Nd0.8Sr0.2NiO2 / SrTiO3, due to the inherently complex chemical processes to stabilize this phase. The SUPERNICKEL project will explore the chemical, structural, physical and electronic properties of new superconducting nickelates, using a transversal approach involving the synthesis of thin films, superlattices and massive materials, the crystallochemistry of the solid, a large battery of macroscopic probes. and experimental microscopic (magneto-transport, X-ray diffraction, photoemission spectroscopy, among others) and theory. Our objectives are to determine the nature and symmetries of the superconducting state, the origin of the interaction forming Cooper pairs, by clarifying the similarities and differences between nickelates and cuprates. Over the past few months, we have focused our efforts on mastering the complex protocol allowing to stabilize the phase of infinite layers and to synthesize the superconducting nickelate.We have already obtained samples with good nominal compositions and close to superconducting instability, and we are confident that very soon, after optimizing their synthesis, we will be one of the few groups in the world to have good quality superconducting nickelates. . In parallel, we will work on other nickelate phases. The possibility of synthesizing and studying in depth, in addition to thin films and superlattices, bulk nickelates will also be a unique approach of SUPERNICKEL. We expect from the thin film / solid material comparison essential and potentially unique information on the specificity of the thin film / substrate form in the emergence of superconductivity. Our multi-approach strategy integrates design, development, detailed crystallochemical characterization, exploration of the physical and electronic properties of normal and superconducting states and theoretical modeling. The SUPERNICKEL consortium thus covers a wide range of know-how in all the essential fields and techniques necessary to tackle this problem: oxide chemistry for the synthesis of massive and thin layers, crystallography, strong correlations, magneto-transport, structure. electronics, magnetism and superconductivity. We also hope that beyond the SUPERNICKEL consortium, the dynamics of this project will become a strong pillar to consolidate and revitalize the French community working in the wider field of new superconductors.