Researchers at the University of Missouri have demonstrated a novel application of photoacoustic spectroscopy to detect molecular vibrations in supersonic flows under near-space cold conditions. This advancement could enhance our understanding of chemical processes in extreme environments, such as those found in interstellar space.
The team, led by Professor Arthur Suits from the University of Missouri and doctoral student Yanan Liu, conducted experiments using a vacuum chamber cooled to approximately 430°F (–250°C), simulating the cold conditions of outer space. Methane gas was introduced into the chamber through a rocket nozzle, creating a supersonic flow. A laser was then directed at the methane molecules, causing them to absorb light and undergo vibrational excitation. These vibrations generated pressure waves, or sound, which were detected using a highly sensitive microphone.
Lechner, P., Ganguly, G., Sahre, M. J., Kresse, G., Dietschreit, J. C. B., & González, L. (2025). Spin Frustration Determines the Stability and Reactivity of Metal–Organic Frameworks with Triangular Iron(III)–Oxo Clusters. Angewandte Chemie International Edition. https://doi.org/10.1002/anie.202514014
Photoacoustic spectroscopy is a technique that measures the sound produced by materials when they absorb light. Traditionally, this method has been challenging to apply in low-pressure, cold environments where sound propagation is limited. However, the researchers’ ability to detect sound in such conditions opens new avenues for studying molecular behavior in environments analogous to those in space.
Professor Arthur Suits from the University of Missouri stated,
“We use the tools of physics to understand how chemistry happens at the highest level of detail possible”. For example, by better understanding exactly how much rotation or vibration an individual molecule has, we can start to gain more fundamental knowledge about the universe we live in, furthering our understanding of astrochemistry.”
Understanding how molecules behave under these extreme conditions is crucial for astrochemistry, as it can provide insights into the formation of stars, planets, and potentially life itself.
Beyond astrochemical research, the techniques developed in this study have potential applications in various industries. For instance, they could be used to improve the detection of trace gases in industrial processes or to monitor chemical reactions in aerospace engineering. The ability to study molecular interactions at low temperatures could also inform the development of new materials and energy systems.
This research represents a significant step forward in the application of photoacoustic spectroscopy under extreme conditions. By demonstrating that sound can be detected from supersonic molecules in near-space cold conditions, the University of Missouri team has opened up new possibilities for studying molecular behavior in environments that closely mimic those found in space.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
