Do coordinating and solvating effects of H2 explain high concentrations of H3+ in interstellar dense clouds? A molecular orbital study of hydrogen cluster ions H3+ to H21

Discovered in glow discharge in 1980, molecular ion H 3 + presented a quantum mechanical enigma that took scientists a decade and a half to solve. Its assigned spectrum helped spot the first signs of its presence among dense interstellar clouds. H 3 + was also thought to be a reactive protonating agent in space. Later, it was also discovered in diffuse clouds. H 3 + owes its ubiquity to the reaction of cosmic rays with the ever-present element in the interstellar space, the hydrogen molecule. Through a description of molecular orbital diagrams, not only the high concentrations of H 3 + , but also high D/H ratios observed in cold interstellar dense clouds can be justified. A series of complexation/solvation mechanisms were used to study ion clusters H 2n +1 + ( n = 1–10). Electrostatic potential charge analysis and typical intrinsic reaction coordinate computations show a Lennard-Jones tailing effect, characteristic of liquid phase behavior, which suggest a solvation mechanism for H 11 + to H 23 + that needs further molecular dynamic computations to get more insight on the kinetics of solvation.