Welcome to the Department of Physics!
How can we produce energy without exhausting the planet? What else can space exploration teach us? How can we treat patients more effectively with proton therapy? Artificial intelligence, friend or foe? And how is Schrödinger's cat doing?
You're asking yourself these kinds of questions, and you'd like to be able to answer them. You'd like to understand, know, solve, experiment, test, code, apply. You'd like to make a commitment to preserving the planet, to health, to society. You'd like to take up the challenge of corporate research, or you'd prefer to put your skills at the service of more fundamental knowledge. By joining the Department of Physics at the University of Namur, you will be satiated and we welcome you with enthusiasm.
Find out more about the Physics Department
Spotlight
Agenda
UNamur Raman Day
An interactive event held at the University of Namur, dedicated to exploring the new Raman microscope and bringing together researchers and industry professionals.
The program includes presentations by experts on Raman microscopy and its applications, hands-on sessions, and a tour of the facilities.
Participants will have the opportunity to interact with specialists from ST Instruments and the Lasers, Optics & Spectroscopies platform during hands-on workshops and networking sessions.
This event allows doctoral students to earn 1 ECTS credit; a certificate of participation can also be issued upon request.
The morning will conclude with a networking lunch, and the afternoon will end with drinks.
This event is free, but registration is required.
Public Defense of a Doctoral Dissertation in Chemical Sciences - Lou D'haese
Raman Optical Activity Signatures of Flexible Systems – Focus on Cryptophane Derivatives.
Abstract
In this work, I aimed to accurately simulate the Raman optical activity (ROA) signatures of flexible solute molecules in their environment. Indeed, these systems are quite challenging due to the potentially huge number of conformers—that is, local minima on the potential energy surface (PES). Furthermore, the environment can drastically alter the PES, as evidenced by experimental ROA spectra that vary significantly depending on the molecule’s conformation and its surroundings. To address this issue, we have developed a hierarchy of methodologies designated M1, M2, and M3. In M1 and M2, the so-called static approach is used: one or more conformers are identified, their geometries are reoptimized at the Density Functional Theory (DFT) level, and their vibrational signatures are simulated, typically using the harmonic approximation. The initial list of conformers was obtained using the CREST algorithm. In M1, the solvent is treated implicitly, whereas in M2, explicit solvent molecules are added around the solute molecule. In M3, we perform ab initio molecular dynamics simulations of the solute molecule surrounded by explicit solvent molecules. The spectrum is obtained by evaluating time-correlation functions along the trajectory. Our first systems of interest were cryptophane derivatives. These are flexible cage-like systems consisting of two hemispheres connected by three -O-(CH₂)n-O- (denoted Cr–nnn) linkers that exhibit chiroptical properties. For Cr–111, the smallest possible cryptophane, the M1 methodology showed good agreement with experimental data, especially in the fingerprint region. However, we demonstrated that the relative ratio between the different conformers was strongly influenced by the choice of the exchange-correlation (XC) functional in our DFT calculations, highlighting the sensitivity of the potential energy surface (PES) description. Cr–222 molecules have been shown to be more flexible, as evidenced by a greater number of significant conformers. The overall agreement with experimental data was also satisfactory. Finally, to test our different approaches (M1–M3), I performed new ROA measurements of amino acids in water at the University of Bordeaux in Dr. Daugey’s laboratory. When compared to our simulations, we clearly observed an improvement in the ROA signatures when explicit water molecules were added to our simulations (M2 vs. M1). Unfortunately, the M3 method did not perform as expected, and further investigation is needed. Overall, I have shown that the PES, as described by our various methodologies, is highly sensitive to various simulation parameters—such as the XC functional, the number and position of explicit solvent molecules, and so on—and that all of these factors strongly influence the simulated ROA signatures.
Jury
- Prof. Francesca CECCHET (UNamur), Chair
- Prof. Vincent LIÉGEOIS (UNamur), Secretary
- Prof. Benoît CHAMPAGNE (UNamur)
- Prof. Carine CLAVAGUÉRA (University of Paris-Saclay)
- Dr. Nicolas DAUGEY (University of Bordeaux)
Public Defense of a Doctoral Dissertation in Physical Sciences—Valentin Job
Development of Antipathogenic Surfaces by Magnetron Sputtering: From Fundamental Mechanisms to Antibacterial and Antiviral Applications
AbstractFrequently touched surfaces (fomites) serve as reservoirs for pathogens, including bacteria and viruses, and act as vectors for contact-mediated transmission. They contribute to the spread of healthcare-associated infections and pose an increased risk during epidemic outbreaks, as highlighted by the COVID-19 pandemic. This thesis focuses on the development of antimicrobial coatings that release silver (Ag) and copper (Cu), deposited by magnetron sputtering. Three coating matrices were investigated: hydrogenated amorphous carbon with or without chromium (a-C:H and Cr/CrN/a-CrC:H) and titanium aluminum nitride (TiAlN). Antibacterial performance was evaluated against Staphylococcus aureus and Escherichia coli. To assess long-term efficacy, the antibacterial properties of the coatings were investigated through successive bacterial exposure cycles. Antiviral activity was evaluated against porcine respiratory coronavirus (PRCV), a member of the Orthocoronavirinae subfamily to which SARS-CoV-2 also belongs. For this purpose, a rapid, high-throughput antiviral screening assay was developed. This innovative method represents a promising approach for the standardized evaluation of antiviral surfaces. In addition to antimicrobial activity, the coatings were required to exhibit adequate mechanical properties and an attractive black appearance suitable for high-touch surfaces. The combination of Ag and Cu exhibited a synergistic effect, enhancing antimicrobial activity and broadening the spectrum of targeted pathogens. Optimization led to a TiAlN coating containing 0.9 at.% Ag and 1.7 at.% Cu, which provided the best balance between mechanical, antibacterial, and antiviral performance. Tribological wear tests confirmed that its antimicrobial efficacy was maintained for up to two years. Prospects for the further development and scientific validation of this prototype are discussed. Jury
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