REACTIONS OF N2H4 WITH O+ AND OTHER IONS AT SUPRATHERMAL ENERGIES

Reaction cross sections, product ion kinetic energies, and chemiluminescence have been measured for N2H4 collisions with O+, Ar+, Kr+, CO+, and CO2+ at collision energies ranging between 1 and 30 eV (center of mass). Charge transfer and dissociative charge transfer occur in all cases; however, the product ion distributions are markedly different for reactions involving the atomic vs the molecular primary ions. The difference is attributed to the greater ability of the molecular ions to share in the partitioning of the reaction exothermicity into internal modes. Time-of-flight studies show that the product ions are primarily formed with thermal or near-thermal (less-than-or-similar-to 100 meV) forward translational energy in the laboratory frame. Chemiluminescence signals attributable to OH A(2)SIGMA+ --> X(2)PI and to NH A(3)PI(i) --> X(3)SIGMA- emissions are observed in collisions between O+ and N2H4 at E(c.m.) = 4-50 eV. The OH emission intensity decreases with increasing collision energy, typical for an exothermic process. The NH emission intensity increases with increasing collision energy, typical for an endothermic process.