PRODUCTION OF WATER-MOLECULES FROM DISSOCIATIVE RECOMBINATION OF H3O+WITH ELECTRONS

Water is probably the most important molecule for the thermal properti es of dense, interstellar gas, and as such plays a decisive role in es tablishing the rate at which molecular clouds collapse towards star fo rmation. The synthesis of water is thought to be mainly due to dissoci ative recombination of H3O+ With electrons,although experiments have, as yet, provided no evidence that H2O is a product of the reaction. He re we present the first observation of water synthesis from the recomb ination of H3O+, with a branching ratio of 33%. This value is in good agreement with existing observations of the [H2O]/[H3O+] ratio in inte rstellar clouds.