GAS-PHASE REACTIONS OF DNO3 WITH X(-)CENTER-DOT(D2O)(N), X=O, OD, O-2, DO2, AND O-3

The gas-phase reactions of DNO3 with anions X(-).(D2O)(n less than or equal to 3), where X = O, OD, O-2, and O-3, in helium at several tempe ratures within the range 185-298 K have been studied using a fast-flow apparatus operated at 0.28 Torr. At room temperature the ions O-.(D2O )(n=1,2), OD-.(D2O)(n=1,2), O-2(-).(D2O)(n=0,1),DO2-.(D2O)(n=0,1), and O-3(-) react rapidly with DNO3 to form mainly bare product ion NO3-. At low temperatures, in the presence of larger hydrates of the reactan t ions, the hydrated species, NO3-. D2O, as well as the (O-2 . DNO3)(- ) and (DO2 . DNO3)(-) product ions from the O-2(-).(D2O)(n=1,2)/DNO3 a nd DO2-.(D2O)(n=1,2)/DNO3 systems, respectively, were seen to be effic iently produced in primary reactions. These ions react further with DN O3 to form (NO3DNO3)(-). Rate constants for the observed reactions wer e determined. The measured rate coefficient for the association reacti on of NO3- with DNO3 shows a temperature dependence and can be represe nted by the expression k(T) = k(298)(298/T)(3.7+/-0.4). The implicatio ns of the present experimental results to atmospheric ion chemistry ar e briefly discussed.