Ion chemistry of NOO +
The kinetics for the reactions of NOO + ions with neutral molecules having ionization potentials (IPs) from 9.27 to 15.58 eV was measured in a selected ion flow tube at 298 K. The NOO + ions are produced from the reaction of N 3+O 2 and have been reacted with the following: NO, C 6F 6, CS 2, CF 3I, C 3F 6, OCS, C 2H 6, Xe, SO 2, O 3, N 2O, CO 2, Kr, CO, D 2, and N 2. Numerous types of reactions were observed with the various neutral reagents, including production of NO + (which may involve loss of an O from the ion or addition of O to the neutral reactant, although the two channels could not be distinguished here), charge transfer, isomerization of NOO + to ONO +, and hydride abstraction. High level theoretical calculations of the structures and energetics of the various isomers, electronic states, and transition states of NOO and NOO + were performed to better understand the observed reactivity. All neutral species with an IP≤11.18 eV were observed to react with NOO + in part by charge transfer. Detailed calculations showed that the recommended adiabatic and vertical IPs of NOO are 10.4 and 11.7 eV, respectively, at the MRCISD(Q)/AVQZ level of theory. The observed experimental limit for charge transfer of 11.18 eV agreed well with the energetics of the final products obtained from theory if dissociation of the neutral metastable product occurred, i.e., the products were X ++[O( 3P)+NO( 2II)], where [O( 3P)+NO( 2II)] formed via dissociation of metastable NOO. Charge exchange with neutral reagent X would, therefore, be exothermic if IP(X)<[IP ad(NOO)-ΔE (O+NO)-NOO]= ∼ 11.1 eV, where IP ad(NOO) is the adiabatic IP. The potential energy surface for the reaction of NOO + with C 2H 6 was also calculated, indicating that two pathways for formation of HNO 2+C 2H 5+ exist. © 2006 American Institute of Physics.
Midey, AJ; Fernandez, AI; Viggiano, AA; Zhang, P; Morokuma, K
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