Energy resolved measurement of endothermic reaction and dissociation thresholds: Fourier transform ion cyclotron resonance mass spectrometry meets guided ion beam

Performance of energy resolved measurements of endothermic reaction and of collision-induced dissociation thresholds can be improved if relative or absolute cross sections are evaluated, rather than product intensities. The calculation of cross sections from measured ion intensities is shown for Fourier transform ion cyclotron resonance mass spectrometry, which provides the link to corresponding experiments with other techniques such as guided ion beam. The peculiarities of the Fourier transform experiment are discussed, and a convolution with the ion kinetic energy distribution is presented for highly accurate threshold fits.