Untersuchung von Ionen-Molekuel- und Ion-Ion-Reaktionen mit einem Ionen Cyclotron Resonanz Massenspektrometer

Abstract

The fundamentals of simultaneous trapping of positive and negative ions in a static electromagnetic trap are described. A typical application of this type of traps is ion cyclotron resonance mass spectrometry (ICR-MS). Analytical expressions for the potentials of common traps are derived, and used to study the dynamics of simultaneously stored positive and negative ions. The theory of motion of ions in ICR-Traps is expanded to deal with simultaneously trapped positive and negative ions. The proper frequencies of stored ions in the field are calculated to the high accuracy needed for precise mass measurements. The predictions for common magnetical traps are improved too. The theory of the duffing oszillator is applied to the motion of ions in a special trap for simultaneous storage of positive and negative ions. Possibilities for ion manipulation are derived. Corresponding experiments verify the predictions about proper frequencies of ions. A new ICR-cell for simultaneous storage of positive and negative ions is studied in detail. The new experimental methods are applied to the study of inert gases, gallium(III)chloride and hexachlorobenzene. Cooling of charged particles by oppositely charged ions is observed, as well as increased speed of reactions with negative ions.