Dr. Matthias KÜBEL
Phone: +49 3641-9-47208
Dr. Kübel leads an Emmy-Noether research group Molecular Movies at the Institute of Optics and Quantum Electronics at the University of Jena. The central goal of the research group is to create Molecular Movies which visualize how molecular structure undergoes transformations, as for example during chemical reactions. This goal requires techniques that provide both ultrahigh spatial and temporal resolution. Moreover, since molecules consist of electrons and nuclei, it is desirable to track the motion of both types of particles simultaneously. We meet these challenges by combining state-of-the art femtosecond light sources with a coincidence spectrometer for detecting ionic fragments as well as photoelectrons.
Dr. Kübel’s research is rooted in strong-field physics, with an emphasis on coincidence spectroscopy. His interests include
- Time-resolved molecular imaging
- Manipulating electronic and chemical dynamics using phase-controlled laser fields
- Correlated ionization dynamics
- Few-cycle laser pulses
- Harmonic generation and interferometry
- Strong-field and attosecond physics
- Non-linear optics
- Cold-Target Recoil Ion Momentum Spectroscopy (COLTRIMS)
- Velocity map imaging
- Multi-color laser fields and femtosecond streaking
- Pump-probe techniques
Key to this achievement was the usage of a previously developed streaking method  where a mid-infrared laser is used to deflect electrons created in its presence. This provides us with a versatile techniques which we want to employ in the future to create Molecular Movies. Interestingly, this new technique can be combined with the capability of COLTRIMS to measure ionic fragments and retrieve the nuclear structure from these measurements.
An example of a molecular movie that shows the motion of nuclei during a chemical reaction is presented in Movie 2. Here, a hydrogen migration takes place in an acetylene ion, such that acetylene (HCCH) isomerizes to vinylidene (CCH2). Our measurement  essentially measures the angle between the two CH bonds and how it varies with time. One can clearly see how the bond angle is initially close to 180° and then shrinks as the hydrogen atom is allowed more time to migrate before it is probed.
 M. Kübel, et al., Nat. Commun. 10, 1042 (2019).
 M. Kübel, et al., Phys. Rev. Lett. 119, 183201 (2017).
 C. Burger, et al., Faraday Discuss. 194, 495 (2016).
 M. Kübel, et al., Nat. Commun. 11, 2596 (2020).
 K. Amini, et al., , Eur. Phys. J. D 75, 275 (2021).
 M. Kübel, et al., Phys. Rev. Lett. 126, 113201 (2021).
In 2020, we have set up a new COLTRIMS apparatus at the Institute of Optics and Quantum Electronics (IOQ). It will serve as the “camera” for our Molecular Movies. Here is a picture: