110 citations · 1k across the 35 of their papers we have counts for
36 papers
Precision spectroscopy of the fine and hyperfine structures of high molecular Rydberg-Stark states: Metrology of molecular hydrogen ions
Ioana Doran, Leon Jeckel, Maximilian Beyer +2
The Stark effect in autoionizing high- Rydberg states decouples the Rydberg electron from the ion core through mixing with core-nonpenetrating high- states. The Ryd…
Metrology of Rydberg states of the hydrogen atom
Simon Scheidegger, Josef A. Agner, Hansjürg Schmutz +1
We present a method to precisly measure the frequencies of transitions to high- Rydberg states of the hydrogen atom which are not subject to uncontrolled systematic shifts cause…
Imaging-assisted single-photon Doppler-free laser spectroscopy and the ionization energy of metastable triplet helium
Gloria Clausen, Simon Scheidegger, Josef A. Agner +2
Skimmed supersonic beams provide intense, cold, collision-free samples of atoms and molecules are one of the most widely used tools in atomic and molecular laser spectroscopy. High…
Observation of quantum capture in an ion-molecule reaction
Katharina Höveler, Johannes Deiglmayr, Josef A. Agner +3
In 1954, Vogt and Wannier (Phys. Rev. 95, 1190) predicted that the capture rate of a polarizable neutral atom or molecule by an ion should increase by a factor of two compared to t…
Precision millimetre-wave spectroscopy and calculation of the Stark manifolds in high Rydberg states of para-H
Nicolas Hölsch, Ioana Doran, Maximilian Beyer +1
Precision measurements of transitions between singlet () Rydberg states of H belonging to series converging on the state of H ha…
Structure and dynamics of HD in the vicinity of the H + D and D + H dissociation thresholds: Feshbach resonances and the role of g/u-symmetry breaking
Maximilian Beyer, Frédéric Merkt
We report on the measurement and analysis of photoionisation, mass-analysed-threshold-ionisation and pulsed-field-ionisation zero-kinetic-energy photoelectron spectra of HD in the…
Characterization of the electronic ground state of Mg by PFI-ZEKE photoelectron spectroscopy
Matthieu Génévriez, Maxime Holdener, Carla Kreis +1
The ground electronic state of the Mg ion has been studied by pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectroscopy. Rotat…
Multipole-moment effects in ion-molecule reactions at low temperatures: part I -- Ion-dipole enhancement of the rate coefficients of the He + NH and He + ND reactions at collision energies near K
Valentina Zhelyazkova, Fernanda B. V. Martins, Josef A. Agner +2
The energy dependence of the rates of the reactions between He and ammonia (NY, Y= {H,D}), forming NY, Y and He as well as NY, Y and He, and the corresponding…
Ion-molecule reactions below 1~K: Observation of a strong enhancement of the reaction rate of the ion-dipole reaction He+ CHF
Valentina Zhelyazkova, Fernanda B. V. Martins, Josef A. Agner +2
The reaction between He and CHF forming predominantly CH and CHF has been studied at collision energies between 0 and ~K in a me…
SI-traceable frequency dissemination at 1572.06 nm in a stabilized fiber network with ring topology
Dominik Husmann, Laurent-Guy Bernier, Mathieu Bertrand +18
Frequency dissemination in phase-stabilized optical fiber networks for metrological frequency comparisons and precision measurements are promising candidates to overcome the limita…
Precision Measurements in Few-Electron Molecules: The Ionization Energy of Metastable He and the First Rotational Interval of He
Luca Semeria, Paul Jansen, Gian-Marco Camenisch +3
Molecular helium represents a benchmark system for testing calculations on few-electron molecules. We report on the determination of the adiabatic ionization e…
Precision measurement of the ionization energy and quantum defects of 39K I
Michael Peper, Felix Helmrich, Jonas Butscher +4
We present absolute-frequency measurements in ultracold 39K samples of the transitions from the ground state to np Rydberg states. A global nonlinear regression of the np1/2 and np…
Benchmarking theory with an improved measurement of the ionization and dissociation energies of H
Nicolas Hölsch, Maximilian Beyer, Edcel J. Salumbides +4
The dissociation energy of H represents a benchmark quantity to test the accuracy of first-principles calculations. We present a new measurement of the energy interval between…
Single-shot Non-destructive Detection of Rydberg Atom Ensembles by Transmission Measurement of a Microwave Cavity
Sébastien Garcia, Mathias Stammeier, Johannes Deiglmayr +2
Rydberg atoms are at the core of an increasing number of experiments, which frequently rely on destructive detection methods, such as field ionization. Here, we present an experime…
High-resolution photoelectron-spectroscopic investigation of the HO cation in its electronic state
Clément Lauzin, Bérenger Gans, Frédéric Merkt
The photoelectron spectrum of water has been recorded in the vicinity of the transition between 112 000 and 116 000 cm$^{…
New method to study ion-molecule reactions at low temperatures and application to the H + H H + H reaction
Pitt Allmendinger, Johannes Deiglmayr, Otto Schullian +4
Studies of ion-molecule reactions at low temperatures are difficult because stray electric fields in the reaction volume affect the kinetic energy of charged reaction partners. We…
Precision measurement of the rotational energy-level structure of the three-electron molecule He
Luca Semeria, Paul Jansen, Frédéric Merkt
The term values of all rotational levels of the He ground vibronic state with rotational quantum number have been determined with an…
Infrared spectroscopy of molecular ions in selected rotational and spin-orbit states
Ugo Jacovella, Josef A. Agner, Hansjürg Schmutz +2
First results are presented obtained with an experimental setup developed to record IR spectra of rotationally state-selected ions. The method we use is a state-selective version o…
Spin-orbit coupling and rovibrational structure in the iododiacetylene radical cation by PFI-ZEKE photoelectron spectroscopy
Katrin Dulitz, Elias Bommeli, Guido Grassi +2
The photoelectron spectrum of the photoionising transition in iododiacetylene, HCI, has been recorded using pulsed-f…
High-resolution spectroscopy of He using Rydberg-series extrapolation and Zeeman-decelerated supersonic beams of metastable He
Paul Jansen, Luca Semeria, Frédéric Merkt
Recently, high-resolution spectroscopy of slow beams of metastable helium molecules (He) generated by multistage Zeeman deceleration was used in combination with Rydberg-seri…
Observation and calculation of the quasi-bound rovibrational levels of the electronic ground state of H
Maximilian Beyer, Frédéric Merkt
Although the existence of quasi-bound rotational levels of the ground state of H has been predicted a long time ago, these states have never been observed. Ca…
Vacuum-ultraviolet frequency-modulation spectroscopy
Urs Hollenstein, Hansjürg Schmutz, Josef Anton Agner +2
Frequency-modulation (FM) spectroscopy has been extended to the vacuum-ultraviolet (VUV) range of the electromagnetic spectrum. Coherent VUV laser radiation is produced by resonanc…
Rydberg states of helium in electric and magnetic fields of arbitrary relative orientation
Ondřej Tkáč, Matija Žeško, Josef Anton Agner +2
A spectroscopic study of Rydberg states of helium ( = 30 and 45) in magnetic, electric and combined magnetic and electric fields with arbitrary relative orientations of the fiel…
Measuring the dispersive frequency shift of a rectangular microwave cavity induced by an ensemble of Rydberg atoms
M. Stammeier, S. Garcia, T. Thiele +5
In recent years the interest in studying interactions of Rydberg atoms or ensembles thereof with optical and microwave frequency fields has steadily increased, both in the context…