Francqui Chair 2025-2026

Created in 1933, the Belgian Francqui Chairs aim to promote cooperation between Belgian universities and to highlight academic excellence.

They allow an invited professor to give a series of lectures and conferences, including an inaugural lecture open to the public, encouraging scientific exchange and fostering meetings between researchers.

Frédéric Merkt is full professor of physical chemistry at the Swiss Federal Institute of Technology (ETH Zurich). His main research interests are in molecular spectroscopy, molecular optics, cold chemistry and precision tests of fundamental physical theories. He received several awards, including the Swiss National Latsis Prize (1999), the William F. Meggers Award of Optica (formerly Optical Society of America (2010)), the van't Hoff Prize of the German Bunsen Society for Physical Chemistry (2012), the Otto Bayer Award of the Bayer Science & Education Foundation (2014), and two ERC advanced grants (2008, 2017). He is member of the German Academy of Sciences Leopoldina and of the Berlin-Brandenburg Academy of Sciences and Humanities, Fellow of the American Physical Society and of the European Physical Society and of Optica.

The Inaugural lecture : 

"100 years after its birth, testing quantum physics with ever-increasing precision: 
the cases of hydrogen and helium"
Wednesday 10 December 2025 at 6:30 PM

The founding articles of quantum mechanics illustrated the new theory with first-principles predictions of the energy-level structure and the spectrum of simple, fundamental atoms and molecules such as the hydrogen atom (H), the helium atom (He), the hydrogen molecular ion (H₂⁺) and the hydrogen molecule (H₂). Over the years, large experimental efforts have been invested to verify the predictions of the quantum theory through measurements, at ever increasing accuracy, of the spectrum of these fundamental few-body systems. On average, a factor of ten in precision of both measurements and calculations is gained every ten years. With the advent of frequency-metrology tools such as atomic clocks, frequency combs, and frequency-distribution networks, it is possible today to measure, in university research laboratories, transition frequencies in these systems with more than 12 significant digits and test the limits of theoretical predictions. Recent attemps at challenging the theory through comparison of experiments and calculations in simple atoms have led to surprises and puzzles, the latest ones concerning the size of the proton and the ionization energy of helium. This lecture will discuss recent precision measurements of the spectrum of the hydrogen and helium atoms carried out with the goals of resolving these puzzles, testing fundamental theory and reducing the uncertainties of fundamental physical constants.

To confirm your attendance Register here

Before this inaugural lecture, a mini-symposium will take place from 4 to 6 PM, aiming at presenting the different research activities centered around quantum physics at UCLouvain. Overview of the event program
 

Location : room CYCL01 in the "Marc de Hemptinne" Building, 
                Chemin du cyclotron 2, 
                B-1348 Louvain-la-Neuve

The following lectures : 

Tuesday, February 10, 2026 – 2:00 PM

Time and Frequency Metrology : The Swiss Frequency-Distribution Network and Its Implementation in AMO Physics Laboratories

Friday, February 13, 2026 – 10:45 AM

Field Sensing and Atom and Molecule Optics with Highly Excited Rydberg States

Tuesday, February 17, 2026 – 2:00 PM

Ion-Molecule Chemistry Near 0 Kelvin: Beyond the Langevin Model

Friday, February 20, 2026 – 10:45 AM

Molecular Spectroscopy: Advances and Future Directions