Nascent rotational and vibrational product state distribution in the charge transfer reaction of N++CO→CO++N at near thermal energy

Abstract

An improved ion beam apparatus is used to measure the nascent product state distribution in the charge transfer reaction N++CO→CO++N under single-collision conditions at 0.16 eV energy. At this energy, the major vibrational channel in the CO+ products is v=1, in contrast to the predominant formation of v=0 at thermal energy. The relative vibrational distribution for the N++CO reaction is (0.40±0.07)v=0 : (0.57±0.04)v=1 : (0.03±0.01)v=2. In the v=0 channel, the rotational distribution under single-collision conditions can be characterized by a Boltzmann distribution with a temperature of T=410±40 K. In the v=1 channel the rotational distribution is highly excited and non-Boltzmann. The lower rotational states approximate a very high temperature of 2000 K. For high rotational quantum numbers (K>23), the rotational temperature is about T=810±20 K. The dramatic differences in the rotational distributions are clear evidence that these two vibrational channels are formed by different reaction mechanisms, most likely a direct reaction for v=0, and an intimate collision for v=1.