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SIMS21, Poland 2017 - Nicholas Winograd abstract

Nicholas Winograd oral presentation (OB1-Thu2-1-4)

GCIB-SIMS with (CO2)n+ projectiles up to 70 keV

Nicholas Winograd1, Dawid Maciążek2, Zbigniew Postawa2, Barbara Garrison3, Nicholas Winograd3

1 Penn State University, 209 Chemistry Bldg, PA 16875 University Park, United States
2 Smoluchowski Institute of Physics, Jagiellonian University, ulica Lojasiewicza 11, 30-348 Krakow, Poland
3 Chemistry Department, Pennsylvania State University, Shortlidge Road, PA 16802 University Park, United States

Gas cluster ion beams (GCIBs) are known to reduce chemical damage, however, the associated low ionization remains problematic for the further applications. The development of the water cluster ion beam [1] and chemically doped Ar-GCIBs [2, 3] has enhanced ionization of protonated molecular ions by induced surface chemical reaction with the projectile. Here, we further explore a CO2-GCIB source operating at a kinetic energy of up to ~ 70 keV with cluster sizes of 1,000~10,000. As expected, the intensity of the protonated and deprotonated molecular species increase with increasing beam energy at the same cluster size, up to E/n ~10 eV/CO2 molecule for organic molecules (e.g., Irganox 1010). Surprisingly, the enhancement of oxygen adducts continues for E/n greater than 10 eV/molecule, presumably as the CO2 molecule begins to experience dissociation which is consistent with the computer simulation. A factor of 50 and 5,000 enhancement is observed using 25 eV/molecule compared to 2.5 eV/molecule from organic and inorganic materials respectively. The kinetic energy of the beam also plays a role, with the higher energy beam delivering higher signal at the same E/n. This feature is further tested on an organic and inorganic mixture consisting of a 10 nm gold coated 50 nm Irganox film. A nearly uniform sputter rate is achieved, leading to the possibility of molecular depth profiling of hybrid systems using a high KE (CO2)n+ GCIB.

[1] S. Sheraz nee Rabbani, A. Barber, J. S. Fletcher, N.P. Lockyer and J. Vickerman. Analytical Chemistry, 85(12), 5654-5658, 2013

[2] A. Wucher, H. Tian and N. Winograd. Rapid communication in Mass Spectrometry, 28(4), 396-400, 2014

[3] H. Tian, A. Wucher and N. Winograd. Journal of The American Society for Mass Spectrometry, 27(2), 285-292, 2016