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Grabow, Jens-Uwe

Visiting Fellows in Sciences

Research field

Spectroscopic search for tiny but important effects.


Jens-Uwe Grabow, a chemist by training, focusses his research interests at molecular structure and dynamics, including intermolecular interactions. Particularly, the precise spectroscopic search for tiny but important effects, too small to be observed with the resolution of already available instrumentation. A breakthrough was his innovation of time-domain microwave spectroscopy: ‘Coaxially Oriented Beam-Resonator Arrangement (COBRA)-FTMW’, a coherence spectroscopy technique, instantaneously increases the accuracy to 0.00000001 cm-1 and increases the sensitivity remarkably.

Besides numerous innovations that turned tedious into routine studies, Jens-Uwe Grabow’s introduction of CAESAR, i.e. ‘Coaxially Aligned Electrodes for Stark-effect Applied in Resonators’, and his coaxial dual parabolic reflector implementation of IMPACT, i.e. I/QModulated Passage-AcquiredCoherence Technique, make the unrivalled COBRA frequency accuracy now available for Stark-effect studies and broadband FTMW experiments, respectively. With his COBRA technique internationally adopted by virtually every laboratory in the field, JUG’s laboratory remains to be the leader in ultimate precision rotational spectroscopy.

Also developing tailored supersonic-jet sources – including LASER-ablation, D/C-discharge, heated, combustion, (LASER-)pyrolysis, and combinations thereof - for in-situ generation and precise investigation of clusters, radicals, diatomics, and complex organic molecules of interest in atmospheric/environmental chemistry, material science, biological sciences, astrophysics, and fundamental physics, he globally attracts scientists of various backgrounds frequently seeking razor-sharp results (63 senior visitors from 47 laboratories in 15 countries since 2004).

Using the capabilities of his spectrometers JUG continues to open new : an exciting field recently explored by him is the use of pure rotational spectroscopy rather than high-energy physics experiments in the quest of finding evidence for ‘New Physics’ in extension to the ‘Standard Model’, which can be evidenced by measuring the abnormal rotational Stark effect of relativistic diatomic radicals. Recently, JUG could show how a FTMW double-quantum (DQ) coherence technique ties the handedness of a chiral molecule unambiguously to the sign of a molecular observable, i.e. the phase of a DQ-induced oscillating macroscopic dipole moment (DQ-polarisation).

Structure Department of Institut für Physikalische Chemie und Elektrochemie (apl. Professor)

Gottfried Wilhelm Leibniz Universität Hannover

Hannover,  Germany