Researchers in Switzerland have discovered that microwave pulses can slow down chemical reactions at low temperatures. This finding, achieved by Valentina Zhelyazkova and colleagues at ETH Zurich, challenges conventional understanding of microwave influence on chemical processes.
The team's innovative setup allowed them to observe how microwave pulses affect reactions between ions and atoms. Unlike typical applications where microwaves heat molecules to increase reactivity, this study revealed a nonthermal mechanism.
The experiment involved a reaction between positively-charged helium ions and neutral carbon monoxide molecules. By cooling the molecules internally to below 10 K, the researchers could observe quantum effects dominating over external noise. This allowed them to confirm that the reaction rate varies based on the rotational state of the CO molecule and can be modified using microwave pulses.
This discovery paves the way for advanced techniques to fine-tune the rate of reactions between ions and neutral molecules. Further research aims to explore these nonthermal mechanisms in more detail, potentially revolutionizing chemical synthesis.