Researchers at the Max Planck Institute for Nuclear Physics (Germany) have recreated the universe's first molecule, helium hydride (HeH⁺), in the laboratory for the first time. It was formed from ionized forms of hydrogen and helium seconds after the Big Bang.
Scientists believe this molecule plays a far more important role in star formation than previously thought. The experiment made it possible to observe collisions between helium hydride and deuterium, a heavy isotope of hydrogen. It turned out that the reaction rate between these particles barely decreases with decreasing temperature, despite previous models predicting the opposite.
Previously, it was assumed that the probability of reactions would drop dramatically at low temperatures, but scientists had been unable to confirm this experimentally or theoretically. It turns out that this reaction leads to the formation of various forms of hydrogen molecules, which act as coolers, helping gas clouds dissipate heat, shrink, and become stars.
During the experiment, helium hydride ions were kept at approximately -267°C for up to a minute before being irradiated with a beam of neutral deuterium. By adjusting the particle speeds, the scientists observed changes in the reaction probability. The findings provide new insights into the chemistry of the early universe and reconsider the role of HeH⁺ in the formation of the first stars.
