Monte Carlo Simulation for Pressurized Experimental Events in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

Abstract

An ion trajectory simulation code based on a stochastic sampling method was developed for pressurized events in Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The ion-neutral interaction was modeled by discrete collisions and was characterized by appropriate probability density functions. The use of randomization allows a more realistic representation of ion behaviors than a conventional approach, such as a viscous drag model. Besides, the proposed simulation can depict a time-varying internal energy, which may provide a useful measure for collisionally activated decomposition processes. The simulation code has been applied to various experimental situations of pressurized events; sustained o#-resonance irradiation, quadrupolar excitation axialization and rf-only-mode trapping. The simulation results revealed the dynamics and the energetics of a trapped ion undergoing these pressurized events.