Roaming Mechanism Discovered for H3+ Formation

Researchers at the University of Michigan (MSU) have unveiled a new perspective on the chemistry of the cosmos. A recent publication in Nature Communications by Peter Pechukas, Marcos Dantus, and colleagues presents findings that challenge previous understandings of how the trihydrogen ion, H3+, forms in space. H3+, often dubbed the "molecule that made the universe," is fundamental to the formation of stars, planets, and potentially life itself. Traditionally, it was believed that H3+ primarily forms when a hydrogen molecule (H2) collides with an ionized form of itself (H2+). However, the MSU team's research indicates a "roaming mechanism" where, instead of immediate separation, the neutral hydrogen molecule "orbits" the remaining fragment of the original molecule, leading to H3+ formation. This process involves a doubly ionized molecule losing two electrons and resulting in a neutral hydrogen molecule (H2) that roams around the original molecule's remains, eventually forming H3+. This roaming mechanism significantly contributes to the overall picture, especially in cold and rarefied molecular clouds where stars are born and where a vast number of exotic organic molecules exist. Understanding how and where H3+ forms is critical for astrochemistry, potentially unlocking the secrets of cosmic kitchens and the origins of life.