Excitation of the z motion of ions in cubic and elongated ion cyclotron resonance cells

Guchte, W.J. van de; Hart, W.J. van der

doi:10.1016/0168-1176(90)80030-7

Cited by 37 publications

(12 citation statements)

References 9 publications

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“…For example, the single-ion response to any of various excitation modes recently analyzed in the limit of quadrupolar trapping potential and spatially uniform RF electric field [23] may now be accurately extended to the trapping and excitation electric potentials of an actual cubic trap. In particular, it should be possible to quantitate the "zejection" phenomenon [23,55,56,[58][59][60], as will be reported in future work. Finally, extension of this program to incorporate the effect of space charge and collisions on the ion spatial distribution and detected ICR signal is underway.…”

Section: Discussionmentioning

confidence: 99%

“…Experimentally, nonlinear behavior of ions during excitation is observed in either a cubic or cylindrical trap, for example, variation in detected relative ion ab~dances at different rates of frequency-sweep excitation (42,(55)(56)(57)(58)(59)(60). Ion ejection by dipolar azimuthal (radial) excitation to a cyclotron radius equal to the radius .of the trap also becomes nonlinear in a spatially nonuniform electric excitation field.…”

Section: Time-varying Electric Excitatian Potential In An Icr Ion Trapmentioning

confidence: 99%

“…Alternatively, a numerical method based on an infinite series expansion of the potential has been used to solve the equations of motion for excitation at twice the axial oscillation frequency, 2Ct1 z [59]. However, that treatment employed a spatial grid of only 10 X 10 X 10 points,~hich did n~t provide sufficient accuracy for comparison to experimental observations.…”

Section: Time-varying Electric Excitatian Potential In An Icr Ion Trapmentioning

confidence: 99%

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Simulated ion trajectory and induced signal in ion cyclotron resonance ion traps

Xiang

Guan

Marshal

1994

J. Am. Soc. Mass Spectrom.

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We present a numerical method for computation of electrostatic (trapping) and time-varying (excitation) electric fields and the resulting ion trajectory and detected time-domain-induced voltage signal in a rectangular (or cubic) ion cyclotron resonance (ICR) ion trap. The electric potential is calculated by use of the superposition principle and relaxation method with a large number of grid points (e.g., 100 × 100 × 100 for a cubic trap). Complex ICR experiments and spectra may now be simulated with high accuracy. Ion trajectories may be obtained for any combination of trapping and excitation modes, including quadrupolar or cubic trapping in static or dynamic mode; and dipolar, quadrupolar, or parametric excitation with single-frequency, frequency-sweep (chirp), or stored waveform inverse Fourier transform waveforms. The resulting ion trajectory may be represented either as its three dimensional spatial path or as two-dimensional plots of x-, y-, or z-position, velocity, or kinetic energy versus time in the absence or presence of excitation. Induced current is calculated by use of the reciprocity principle, and simulated ICR mass spectra are generated by Fourier transform of the corresponding time-domain voltage signal.

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Section: Discussionmentioning

confidence: 99%

Section: Time-varying Electric Excitatian Potential In An Icr Ion Trapmentioning

confidence: 99%

Section: Time-varying Electric Excitatian Potential In An Icr Ion Trapmentioning

confidence: 99%

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Simulated ion trajectory and induced signal in ion cyclotron resonance ion traps

Xiang

Guan

Marshal

1994

J. Am. Soc. Mass Spectrom.

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“…[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] This ejection, called z-ejection, may occur even at a low excitation level such as that used for SORI. However, its contribution to loss of precursor ions in a real SORI collisional activation event is questionable because the trapping oscillation is an inherently stable mode and can be further stabilized by ion-neutral collisions.…”

mentioning

confidence: 99%

Simulation for internal energy deposition in sustained off-resonance irradiation collisional activation using a Monte Carlo method

Fujiwara

Naito²

1999

Rapid Commun. Mass Spectrom.

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This paper proposes a novel computational approach employing a Monte Carlo method, aimed at an improved understanding of the dynamics and energetics of activated ions in sustained off-resonance irradiation collisionally activated dissociation (SORI-CAD) experimental events of Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). In SORI-CAD events, internal energies of activated ions are complicatedly associated with their motion undergoing off-resonance excitation (i.e. alternate accelerations and decelerations) and inherently stochastic ion-neutral collisions. Several types of pseudo-random generators were adapted to probability density functions (PDFs) which characterize the ion-neutral collision process. Simulated ion trajectories involve the realistic feature of pressurized SORI-CAD events, such as a collisional damping and those which have not been illustrated in conventional analytical approaches. The proposed method can simulate the time-varying translational and internal energies of activated ions. The present result suggests that the internal energy of a SORI-activated ion should be inversely proportional to the cube of the SORI excitation frequency offset. Copyright 1999 John Wiley & Sons, Ltd.

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“…Such calculations show how ion loss due to z ejection by dipolar radial excitation at2w z and oo., + 2w. could arise from coupling of axial and radial motion during broadband excitation of initia lly off-axis ions [12][13][14][15][16][17][18][19]. However, in typical FT-ICR experiments, ions are formed on or very close to the centralz axis of the trap , where there is no radial excitation electric field component.…”

mentioning

confidence: 99%

Simulated ion trajectory and induced signal in ion cyclotron resonance ion traps. Effect of ion initial axial position on ion coherence, induced signal, and radial or z ejection in a cubic trap

Xiang

Marshall²

1994

J. Am. Soc. Mass Spectrom.

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The effects of ion initial axial position on coherence of ion motion, induced ion cyclotron resonance (ICR) signal. and radial and z ejection have been evaluated by numerical simulation for a cubic Fourier transform-ion cyclotron resonance ion trap. For a given initial ion cyclotron phase and radius, ions of different initial z position are shown to be excited to significantly different ion cyclotron radii (and ultimately radially ejected at significantly different excitation amplitude-duration products). Ion initial z displacement from the trap midplane affects observed ICR signal magnitude in two ways: (1) for the same postexcitation cyclotron radius, an ion with larger initial z displacement induces a smaller ICR signal and (2) an ion with larger initial z displacement is excited to a smaller cyclotron radius. We also evaluate the induced ICR signal as a function of excitation amplitude-duration product for spatially uniform or Gaussian ion initial z distributions. In general, if the excitation waveform contains components at frequency, 2 ωz or (ω+ + 2 ωz, in which ωz is the axial C"trapping") oscillation frequency, then ejection occurs axially. However, the resulting excitation amplitude-duration product for such axial ejection is significantly higher (factor of, ∼ 4) than that required for radial ejection (at ω+) for ions of small initial radius. The present results offer the first explanation of how, even if the ion is initially at rest on the z axis (i.e., zero excitation electric field amplitude on the z axis), z ejection (axial ejection) may nevertheless occur if the excitation waveform contains frequency components at ω+ + 2ωz and/or 2w z Namely, our simulations reveal that off-resonant excitation pushes ions away from the z axis, after which the ions are exposed to z excitation and eventual z ejection.

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Excitation of the z motion of ions in cubic and elongated ion cyclotron resonance cells

Cited by 37 publications

References 9 publications

Simulated ion trajectory and induced signal in ion cyclotron resonance ion traps

Simulated ion trajectory and induced signal in ion cyclotron resonance ion traps

Simulation for internal energy deposition in sustained off-resonance irradiation collisional activation using a Monte Carlo method

Simulated ion trajectory and induced signal in ion cyclotron resonance ion traps. Effect of ion initial axial position on ion coherence, induced signal, and radial or z ejection in a cubic trap

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