Reactions of Boron Oxide and BnOmH+Cluster Ions with Water

Reactions of B n O m + and B n O m H + clusters ( n ≤ 3, m ≤ 4) with D 2 O have been studied over a collision energy range from 0.1 to 10 eV (center of mass). The reactivity and product branching are found to be highly dependent on the structure of the reactant ion. When available, the preferred site of attack is on a terminal B atom, and the chemistry is dominated by O and OD addition. Even for the most reactive clusters the peak reaction efficiency is only 5−7%, indicating the presence of a bottleneck to reaction. When the reactant has no terminal B atoms, reaction is 1 order of magnitude less efficient and appears to be dominated by attack at nonterminal B atoms. The B n O m H + react similarly, suggesting that the added H atom does not block the reactive sites. This is in contrast to the isoelectronic reaction with HF, where H addition decreased reactivity dramatically. The results are compared with those for related reactions, and with recent ab initio results. In general, theory is consistent with experiment; however, there remain a few problem species.