Equipment of the Suhm group

Our group continues to develop a range of powerful instruments to investigate intermolecular interactions. Several of them are one-of-its-kind, although they typically function on fairly elementary principles. A (typically pulsed) supersonic jet expansion is crossed by infrared or visible radiation and the absorption or inelastic scattering of the light is detected.

We like to use acronyms for some of our experiments, in particular in our lab jargon. These acronyms have to fulfil several requirements: They should be built from letters contained in an expression which describes a key working principle of the setup. They should sound like a word which is understood internationally. This is often the case for popular food items. There should also be some kind of analogy between the international meaning of the acronym and an aspect of the experiment. Sometimes there are hidden meanings as well.

Here are some short descriptions and visualizations of some of our experiments:


Chilli - Chemical imaging by spatially resolved infrared spectroscopy

The chilli-jet enables the space-resolved (2D), synchronous recording of FTIR spectra of supersonic expansions with a focal plane array (FPA) detector. Compared to mapping techniques, this area detector allows for a considerable reduction of recording times and substance consumption, as well as better reproducibility ... continue reading

Chilli-jet picture


Curry - Classical unrestricted Raman spectroscopy

The curry-jet is a versatile custom spectrometer that combines Raman scattering with supersonic jet-cooling to investigate molecular interactions and conformational preferences. Substances are evaporated and picked up by ... continue reading



Gaseous samples seeded in helium or other carrier gas mixtures are introduced into the Teflon-coated reservoir and expanded into the vacuum chamber through a narrow (0.2 mm) but extremely long (600 mm) slit nozzle (fine - but lengthy). This nozzle length enables recording of FTIR spectra with highest sensitivity ... continue reading



The gratin-jet, the successor of the filet-jet, is currently in its first test phase.



Popcorn - Poppet-controlled resistively heated nozzle

The popcorn-jet allows FTIR measurements of low-volatile compounds. The sample is melted onto molecular sieve pellets and enclosed between check-valves to avoid leakage during off-times. A gas pulse (0.3 s) from a 69 L reservoir picks up the sample and is supersonically expanded via a slit nozzle into a buffer volume ... continue reading

popcorn-jet image