An energy-filtering device coupled to a quadrupole mass spectrometer for soft-landing molecular ions on surfaces with controlled energy

Abstract

We have developed an energy-filtering device coupled to a quadrupole mass spectrometer to deposit ionized molecules on surfaces with controlled energy in ultra high vacuum environment. Extensive numerical simulations as well as direct measurements show that the ion beam flying out of a quadrupole exhibits a high-energy tail decreasing slowly up to several hundred eV. This energy distribution renders impossible any direct soft-landing deposition of molecular ions. To remove this high-energy tail by energy filtering, a 127° electrostatic sector and a specific triplet lenses were designed and added after the last quadrupole of a triple quadrupole mass spectrometer. The results obtained with this energy-filtering device show clearly the elimination of the high-energy tail. The ion beam that impinges on the sample surface satisfies now the soft-landing criterion for molecular ions, opening new research opportunities in the numerous scientific domains involving charges adsorbed on insulating surfaces.

The production of ultra-high purity single isotopes or tailored isotope mixtures by ICP-MS

“…In addition, the range of enriched isotopes available and their purities are fairly restricted and the cost of tailoring isotopic composition of an element for some specific application is usually cost prohibitive. In recent years a small number of publications have appeared applying the same approach to selectively implanting organic molecules by mass spectrometry [7,8], although preserving their structure and chemical functionality has remained problematic.…”

Electrospray deposition of organic molecules on bulk insulator surfaces

“…For such ESI deposition systems, the combination with filtering devices, made of quadrupoles, octopoles and other electrostatic stages allows one to filter ions and guide them towards the sample surface [7][8][9][10]. An advantage of theses systems, in addition to the selection of the ion species, is the use of a soft landing deposition where additional electrostatic lenses are used to reduce the kinetic energy of the molecules [11][12][13]. Moreover it lowers the chance of fragmentation by impacting surfaces.…”

Electrospray deposition of organic molecules on bulk insulator surfaces

“…For such ESI deposition systems, the combination with filtering devices, made of quadrupoles, octopoles and other electrostatic stages allows one to filter ions and guide them towards the sample surface [ 7 – 10 ]. An advantage of theses systems, in addition to the selection of the ion species, is the use of a soft landing deposition where additional electrostatic lenses are used to reduce the kinetic energy of the molecules [ 11 – 13 ]. Moreover it lowers the chance of fragmentation by impacting surfaces.…”