Influence of the internal excitation of FeCO+ on its reactivity with O-2 observed in Fourier Transform-ICR cell

The reaction kinetics of electron impact ionization generated FeCO+ cations with Oz is investigated using a triple-cell Fourier Transform Ion Cyclotro n Resonance spectrometer. Two reaction channels are observed: (1) exothermi c formation of FeO+ with oxidation of the CO ligand; (2) slightly endotherm ic ligand substitution giving FeO2+. Residual water also reacts on FeCO+ an d FeO2+. Varying the relaxation delay of ions before reaction allowed us to study the radiative relaxation of FeCO+. Three groups of differently excit ed states of FeCO+, termed as (FeCO+)**, (FeCO+)* and (FeCO+)(0) by order o f decreasing internal energy, can be differentiated according to their diff erent reactivities. While (FeCO+)(**) and (FeCO+)(*) lead to FeO2+, only (F eCO+)(0) gives FeO+. (C) 2001 Elsevier Science B.V. All rights reserved.