The border between chemistry and quantum mechanics is a slippery and difficult terrain to navigate. And detecting how exactly the tunneling effect takes place in a chemical reaction, that strange property of particles that allows them to pass through barriers as if they did not exist, is extremely complicated. In fact, if the exact quantum mechanical description of chemical reactions with three particles is already difficult, with more than four it becomes practically impossible. Therefore, theorists are forced to simulate these types of reactions using only classical physics, completely ignoring quantum effects. Achieving experiments capable of combining both worlds would represent a huge advance in a multitude of fields, from engineering to astrophysics. But where exactly is the border between these two realities? Now, a team of researchers led by physicist Roland Wester, from the University of Innsbruck, has just achieved what seemed impossible. In Wester's own words, exploring this elusive frontier "requires an experiment that allows measurements that are sufficiently precise so that it can still be described mechanically, but also with quantum physics. The idea came to me 15 years ago in a conversation with a colleague during a conference in the United States. "I wanted to trace the quantum-mechanical tunneling effect in a very simple reaction." Related News standard No Google, one step closer to getting the long-awaited quantum computer Patricia Biosca The magazine 'Nature' publishes a study in which researchers from the Google Quantum AI division propose an error correction code Wester then got down to business. work and, because the tunneling effect makes the reaction very unlikely, its experimental observation was extraordinarily difficult. Despite this, and after several failed attempts, Wester and his team have just achieved their goal for the first time. The work has just been published in 'Nature'. A crucial experiment For their novel experiment, the researchers chose hydrogen, the simplest element in the Universe. Thus, they introduced deuterium (an isotope of hydrogen) into an ion trap, cooled it, and then filled the trap with hydrogen. Due to the low temperature, the deuterium ions did not have enough energy to react with hydrogen molecules in the classical way. But on very rare occasions, however, that reaction still occurred. These rare reactions are precisely those that were caused by the tunneling effect. «Quantum mechanics – explains Robert Wild, first signatory of the study – allows particles to cross the energy barrier due to their quantum wave properties, and a reaction occurs. In our experiment, we gave the possible reactions in the trap about 15 minutes and then determined the number of hydrogen ions formed. “From their number, we were able to deduce how often a reaction occurred.” Back in 2018, theoretical physicists calculated that in a system like this, quantum tunneling would occur in only one in every hundred billion collisions. Something that practically coincides with the results of this study. After 15 long years of research, the experiment confirms for the first time a precise theoretical model for the tunneling effect in a chemical reaction. Countless Applications Of course, there are other types of chemical reactions that could also benefit from tunneling. From this moment, and thanks to this first experimental measurement, researchers will be able to develop simpler theoretical models for chemical reactions in the future, and test them in the reaction that has now been successfully demonstrated. MORE INFORMATION news No The banquet of a black hole, live news Yes Surprise at the discovery of an 'old' galaxy in the early Universe The tunneling effect, in fact, is used in fields as different as electron microscopy or the development of more efficient flash memories. And it is also used to explain the alpha decay of atomic nuclei. Thanks to this effect it is also possible to explain some types of synthesis of molecules in deep space, inside dark interstellar clouds. In short, Wester and his team's experiment has laid the foundations for better understanding a large number of chemical reactions.
