Electrons in cobalt atoms have been caught breaking the rules of how they are supposed to relax after being hit by light.

For years, chemists used iron-based molecules to set the rules for how electrons move and settle after an energy boost. This study on cobalt complexes shows that those rules are not universal and can actually be completely reversed. Instead of falling through the expected energy levels, the cobalt electrons took a forbidden path and got trapped in a different state. This triplet trapping happened because of the way the molecule's shape and vibrations interacted with the electrons. Knowing this allows us to design better solar cells and light-driven catalysts that do not waste energy the way we expected. It proves that chemical behavior is much more customizable than we previously thought.