Publications of Interest

 

 Here is presented a selection of my publications. You can find all my publications on Google Scholar or Research Gate.

 

Arsène Chemin, Mohan Kumar Kuntumalla, Maria Brzhezinskaya, Tristan Petit, Alon Hoffman (2024), Applied Surface Science, 160082. 

Did you know diamonds could revolutionize quantum sensing technology? 💎🔬 But achieving near-perfect surfaces is key. Our work introduces a novel model for energy-dependent X-ray photoelectron spectroscopy, enabling atomic-level depth profiling of surface chemistry. Excitingly, we uncover the formation of graphene-like islands!  But the excitement doesn't end there. Our analysis using X-ray absorption spectroscopy unveils the position of unoccupied surface states within the diamond bandgap, offering more insights into stabilizing near-surface NV− centers. 

Diamond materials are proposed as a promising emitter of solvated electrons, and visible light excitation would enable solar-driven CO2 or N2 reductions reactions. But diamonds are transparent to visible light and sub-bandgap excitation remains challenging. In this work, the role of surface states on diamond materials for charge separation and emission in both gaseous and aqueous environments. 

This work illustrates how combining synchrotron base X-ray spectroscopy, which is surface sensitive, and lab-based measurements helps us to understand the 'impossible' excitation of diamond by visible light. 

Kiendl, B., Day, A., Choudhury, S., Buchner, F., Atak, K., Chemin, A., ... & Krueger, A. (2022). Preprint

Diamonds have unique properties! When excited by UV light, they can emit electrons, which can be used for CO2 reduction. But one need some trick… Overcoming the energy barrier in CO2 reduction is a key avenue in the development of sustainable carbon capture and recycling systems spearheading against the climate emergency. Diamond, a wide-bandgap material, has shown promise in this aspect due its ability to produce highly reductive solvated electrons when irradiated with deep UV light. This requirement for high-energy optical illumination, however, hampers its sustainable application and limits its useful lifetime. Here we show the photosensitization of nanoscale detonation diamond in reductive photoelectrocatalysis through surface functionalisation with a ruthenium-based dye, demonstrating solar-light driven turnover of CO2 using the unique properties of diamond. 

Chemin, A., Fawaz, M. W., & Amans, D. (2022). Applied Surface Science, 574, 151592. 

Laser ablation produces shockwaves similar to explosion blasts. Observing them enables to determine the enormous pressure obtained. Shockwaves propagation are reconstructed using time-resolved shadowgraph imaging. The propagation in air is well-described by Taylor–von Neumann–Sedov’s theory for over-pressure at the shock front larger than ten times the atmospheric pressure, but the energy distribution appears to be anisotropic and mostly directed in the normal direction to the target’s surface. The shockwaves velocity in water is hypersonic during 50 ns and then reaches the sound velocity. Pressure values at the shock front are compared using two different approaches, accounting for different state’s equations. In both cases, the ablation pressure is found out to reach several GPa and increases as the square root of the laser intensity. 

 Chemin, A., Ross, A., Hermelin, S., Crozet, P., Motto-Ros, V., Ledoux, G., ... & Amans, D. (2023). Spectrochimica Acta Part B: Atomic Spectroscopy, 106685. 

Are molecules in laser-generated plasma at equilibrium? How can we probe their ground state? Here, we show that laser-induced fluorescence can be used to gather new information! In this article, we investigate thermodynamic equilibria from ro-vibrational population distributions in the AlO molecule. Using laser induced fluorescence spectroscopy, we can directly probe the population of the rotational levels in the ground electronic state X2Σ+ of AlO and deduce the corresponding rotational temperature. In such plasma, AlO molecules in the excited state are believed to be formed by chemical reaction and might be strongly out of equilibrium, but we find that emission from the B2Σ+ excited state provides a useful indication of kinetic temperature of the species in the plasma for delays longer than a few microseconds. 

Chemin, A., Lam, J., Laurens, G., Trichard, F., Motto-Ros, V., Ledoux, G., ... & Amans, D. (2019). Nanoscale Advances, 1(10), 3963-3972. 

Laser ablation in liquid of a solid target can be used to produce nanoparticles. But can we dope this nanoparticles using the liquid environment? In this paper, we show that pulsed laser ablation of an undoped solid target in an aqueous solution containing activator ions offers a new way to synthesise doped-nanoparticles. The doping efficiency is evaluated for laser ablation of an undoped Gd2O3 target in aqueous solutions of EuCl3. Thanks to luminescence experiments, we show that the europium ions penetrate the core of the nanoparticles. The concentration of the activators in the nanoparticles is proportional to the initial concentration in the aqueous solution. On the one hand, this work could open new ways for the synthesis of doped nanomaterials. On the other hand, it also raises the question of undesired penetration of impurities in laser-generated nanoparticles in liquids. 

Chemin, A., Miyajima, K., Melinon, P., Mafuné, F., & Amans, D. (2020). The Journal of Physical Chemistry A, 124(11), 2328-2334.

Can we describe the nucleation processes in a cluster source? Are the clusters formed in the thermodynamic stable state? Nucleation kinetics in gas phase remains an open issue with no general model. The derivation of the reaction constants assuming a canonical ensemble fails to describe anisotropic materials such as oxides. We have developed a general and versatile model using activated complex kinetics with a microcanonical approach. This approach handles the kinetics issue in cluster growth when the transient nature of the processes hinders the use of the canonical ensemble. The model efficiently reproduces experimental size distributions of alumina clusters formed by laser ablation with different buffer gas densities, including magic numbers. We show that the thermodynamic equilibrium is not reached during the growth.