Auftrittspotentialmessungen an ionisierten Molekülbruchstücken mit kinetischer Anfangsenergie

Abstract

A 60°-magnetic mass spectrometer of high sensitivity (smallest detectable signal ca. 10^-19 amps) has been used for the measurement of appearance potentials of high kinetic energy fragment ions from propane. The appearance potential values show that these ions originate both from singly and doubly charged molecular ions. The ions C₂H₅ ⁺, C₂H₃ ⁺, C₂H₂ ⁺, CH₃ ⁺, CH⁺, H₂ ⁺, and H⁺ are produced by at least two reactions. However, only one process was found for the ions C₂H₄ ⁺ and C₂H⁺. The calculated and measured appearance potentials agree within some tenths of a volt. The kinetic energy was measured by the deflection method. The accuracy in the determination of appearance potentials is largely determined by the high resolution in kinetic energy measurement.