Cross section and product time-of-flight measurements of the reaction of N+2 with H2O and D2O at suprathermal energies

Abstract

Charge exchange and hydrogen atom pickup cross sections, and product ion time-of-flight measurements are reported for N+2 –H2O(D2O) collisions at center-of-mass collision energies ranging between 1 and 15 eV. No isotope effect is detected for the charge exchange branch, while a significant isotope effect is observed for the atom pickup reaction. Throughout the measured energy range, the time-of-flight measurements show that the H2O+(D2O+) charge exchange product is produced with near-thermal energy in the laboratory frame, implying little or no momentum transfer. The charge exchange reaction products are therefore formed with internal energy comparable to the exothermicity of the reaction (2.96 eV). The atom pickup ion product velocity distributions and the atom pickup isotope effect are consistent with a spectator stripping mechanism.