Collision-Induced Dissociation of Cr₂(CO)_y⁺ (y = 4-7)

Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry has been applied to the study of energy-resolved collision-induced dissociation of Cr₂(CO)_y⁺ (y = 4-7) prepared during the clustering reactions initiated by the dissociative ionization of Cr(CO)₆. Mass-selected precursor ions were activated by translational energy-controlled collisions with helium. Threshold curves for the dissociation products were analyzed using model functions convoluted with a Doppler broadening distribution function. For one CO ligand loss from Cr₂(CO)₄⁺, Cr₂(CO)₅⁺ and Cr₂(CO)₇⁺, the threshold values were determined to be 1.26 �} 0.11, 1.92 �} 0.16 and 1.35 �} 0.12 eV, respectively, at 298 K. In the case of Cr₂(CO)₆⁺, the lowest energy channel was chromium ion elimination with a threshold of 1.47 �} 0.12 eV.