Non-destructive detection of large molecules without mass limitation

Abstract

The problem for molecular identification knows many solutions which include mass spectrometers whose mass sensitivity depends on the performance of the detector involved. The purpose of this article is to show by means of molecular dynamics simulations, how a laser-cooled ion cloud, confined in a linear radio-frequency trap, can reach the ultimate sensitivity providing the detection of individual charged heavy molecular ions. In our simulations, we model the laser-cooled Ca + ions as two-level atoms, confined thanks to a set of constant and time oscillating electrical fields. A singly-charged molecular ion with a mass of 10 6 amu is propelled through the ion cloud. The induced change in the fluorescence rate of the lather is used as the detection signal. We show that this signal is due to a significant temperature variation triggered by the Coulombian repulsion and amplified by the radio-frequency heating induced by the trap itself. We identify the optimum initial energy for the molecular ion to be detected and furthermore, we characterize the performance of the detector for a large range of confinement voltages.

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• About the dynamics and thermodynamics of trapped ions
• Metastable level lifetimes from electron-shelving measurements with ion clouds and single ions
• Ion dynamics in a linear radio-frequency trap with a single cooling laser
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Cited by in corpus (3)

• The physics and applications of strongly coupled plasmas levitated in electrodynamic traps
• Thermal bistability in laser-cooled trapped ions
• Fluorescence calorimetry of an ion crystal