Computer-Assisted Ion Cyclotron Resonance Appearance Potential Measurements for C₅H₁₀ Isomers

We have designed a simple computer-ion cyclotron resonaece spectrometer interface which permits fast, accurate data acquisition as well as the rapid and precise determination of ionization and appearance potentials. In this paper we describe-the use of the new system for the measurement of ionization potentials of a variety of C₅H₁₀ isomers and the appearance potentials for their two major fragment ions (C₄H₇+ and C₃H₆+). The purpose of the research described was to develop a method for the rapid, routine and accurate measurement of appearance potentials for both molecular and fragment ions. Additionally, we wished to provide on-line operator interaction during both the data acquisition and analysis stages of the experiment. The C₅H₁₀ compounds (virtually indistinguishable by conventional mass spectrometry) were chosen as a suitable test series to permit evaluation of the system. The appearance potentials thus obtained were reproducible within 0.1 eV and agreed well with previous values, in those cases where such values were available, thus verifying the achievement of our objectives.