Excitation of Ions by High-harmonic Frequency Components in Paul and Penning Traps and Ion Guides. I. Selective Simultaneous Dipolar Excitation of High Charge States with Clipped Sinusoidal and Non-harmonic Waveforms in a Linear Quadrupole Ion Guide

This article presents a method for simultaneous excitation of multiple high charge states of a molecular ion in Paul or Penning trap. Using a linear quadrupolar ion guide we validate the method by using a variety of time- domain excitation waveforms with high harmonics of the first charge state's resonant frequency. The proposed way of inducing harmonics is the deliberate distortion of the excitation waveform from its sinusoidal form. In order to facilitate interference of the harmonics, a superposition of two sinusoids different by a frequency factor of two is used. The simplest form of distortion - amplitude restriction - of such waveform produces interference of the harmonics and results in selective excitation of charge states. Multiple protonation states of melittin were used as a model in this study.