© University of Bremen; Previous approaches to the description of the molecular diameter

© University of Bremen; Mass flow in microchannels as a function of the scale range of the free molecular path length

© University of Bremen; Scale range of the average free molecular path length

More exact measurement of gas molecules

The diameter of gas molecules is an important property for numerous scientific and technical disciplines. Various measurement methods already exist, but their results diverge in certain cases. This is especially true for gas molecules that exist in an environment in which the pressure is lower than the normal atmospheric pressure, in rarefied gases like a vacuum e.g. Scientists from the University of Bremen have now developed a model that can be used to determine the diameter of molecules in rarefied gases that are in a transition region between a continuum flow and a free molecular flow. In a continuum flow or viscous flow, gas molecules behave approximately the same, while in a free molecular flow they are so far apart from each other that virtually no interactions occur and in mathematical descriptions of the flow each molecule must be considered individually.

Why is the diameter of a gas molecule of importance?

The size of a molecule has a strong influence on its mobility and is thus a central property in many natural processes and technical applications. It affects chemical reactions and defines the air drag on wind turbines. Molecular size also plays a key role in the question of how quickly the lungs can absorb oxygen or gases diffuse across membranes.

Link zum Paper: www.nature.com/articles/s41598-022-05871-y

Scientific inquiries:
Prof. Dr. Rodion Groll
0421 218-57832

Media inquiries:
Birgit Kinkeldey
0421 218-57755