Merkt leads the Molecular Physics and Spectroscopy group at ETH D-CHAB. Research directions: (1) High-resolution XUV/VUV spectroscopy — using synchrotron radiation and table-top laser sources to study molecular Rydberg states, ionization thresholds, and ro-vibrational structure at sub-MHz precision; (2) Precision molecular clock transitions — proposing and measuring molecular transitions suitable for fundamental constant variation searches (μ, α); (3) Metastable atom and ion trapping — developing new trapping methods for precision spectroscopy of exotic species; (4) Pulse and Fourier transform microwave spectroscopy — rotational spectroscopy of transient species. Direct applications to molecular quantum sensing and fundamental physics.