Quantum tunneling observed in heavy fluorine atoms for first time

A recent study has, for the first time, observed quantum tunneling in heavy fluorine atoms, breaking the long-held "fluoro wall" belief that such heavy atoms cannot tunnel. Quantum tunneling is a phenomenon where particles pass through energy barriers they classically shouldn’t overcome. Previously, tunneling had been mostly seen in very light atoms like hydrogen, oxygen, and nitrogen. Researchers discovered this effect by trapping fluorine atoms in a frozen neon matrix at –270°C and using infrared spectroscopy to analyze unusual signals from a negatively charged ion composed of five fluorine atoms (F₅⁻). The central fluorine atom in this ion was found to tunnel between two equivalent positions, a behavior confirmed by quantum mechanical simulations. This breakthrough challenges existing views in quantum chemistry, suggesting that tunneling may occur more widely, even in heavier atoms under certain conditions. The finding has significant implications for understanding fluorinated compounds, which are important in pharmaceuticals, battery technology, and environmental science. For instance, fluorinated groups enhance drug absorption and battery efficiency, while fluorine-rich pollutants like PFAS are notoriously persistent in the environment. Understanding and potentially controlling fluorine tunneling could lead to new methods for breaking down such pollutants or designing advanced materials and medicines.