H(2) roaming chemistry and the formation of H(3)(+) from organic molecules in strong laser fields

Roaming mechanisms, involving the brief generation of a neutral atom or molecule that stays in the vicinity before reacting with the remaining atoms of the precursor, are providing valuable insights into previously unexplained chemical reactions. Here, the mechanistic details and femtosecond time-resolved dynamics of H(3)(+) formation from a series of alcohols with varying primary carbon chain lengths are obtained through a combination of strong-field laser excitation studies and ab initio molecular dynamics calculations. For small alcohols, four distinct pathways involving hydrogen migration and H(2) roaming prior to H(3)(+) formation are uncovered. Despite the increased number of hydrogens and possible combinations leading to H(3)(+) formation, the yield decreases as the carbon chain length increases. The fundamental mechanistic findings presented here explore the formation of H(3)(+), the most important ion in interstellar chemistry, through H(2) roaming occurring in ionic species.