Hydride abstraction by NO+ from ethanol: Effects of collision energy and ion rotational state

The effects of NO+ rotational state and collision energy on the reaction NO ++C2H5OH --> HNO+C2H4OH+ were studied in a guided-ion-beam instrument over the collision energy range from 50 meV to 3.7 eV. Integral cross sections f or the reaction are presented. NO+ is prepared in specific rotational level s (N+ = 0,1 and N+ = 10) by means of mass-analyzed threshold ionization. Ab initio calculations were used to probe stationary points on the potential energy surface. The reaction is sharply inhibited by collision energy, sugg esting a bottleneck for reaction. If rotational energy had a similar effect , similar to 50% inhibition from N+ = 10 excitation would be observed at lo w collision energy. Instead, rotation is found to have no effect within exp erimental error. A precursor complex mechanism is proposed to explain the r esults. (C) 2000 American Institute of Physics. [S0021-9606(00)00232-4].