Collisionally FTICR

Gas-phase ions may be fragmented by photoexcitation (PID), particularly by IR photons tuned to the vibrational frequency of covalent bonds. The cross section of an ion for photon absorption is low compared with its collisional cross section, so PID is most commonly associated with the use of intense light sources (lasers) and FTICR where the period the ion is exposed to the photons can be lengthened to increase the... 

The coordination of transition metals is known to influence the keto-enol tautomerism in the condensed phase" . The effect of coordination of bare Fe+ ions on the keto-enol equilibrium of phenol was investigated by means of generation of various cyclic [Fe,Cg, He, 0]+-isomers. These isomers were characterized by collisional activation (CA) and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry" . It was shown that the energy difference between the phenol-iron complex 65 and the keto isomer 66 is not perturbed by the presence of the iron cation in comparison with the uncom-plexed isomers 3 and 4 (equation 25). Thus, the energy difference for both the neutral and the Fe+-coordinated systems amounts to ca 30 kJ moC in favor of the phenolic tautomer. 

The hydrogenolysis reaction proceeds at a near collisional rate, but the activation of methane, the reverse reaction, does not proceed at a measurable rate in the FTICR. Thus the equilibrium constant (=kf/kj.) for Equation 1 is > 1, and the product Zr-H homolytic bond dissociation enthalpy, D(Cp2Zr -H), is therefore greater than D(Cp2Zr -CH3) since D(H-H) = D(H3C-H) =... 

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