ISSN:
0951-4198
Schlagwort(e):
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Physik
Notizen:
Dynamically-correct branching ratios can be measured in a XQQ tandem mass spectrometer (MS/MS) under single-collision conditions when the key MS/MS parameters are properly selected to correct for reaction-induced mass discrimination within the RF-only quadrupole mass filter (Q2). The energy dependence of the cross-section, σ(E), for the reaction N2+· + SF6 → N2+SFx+ (x = 1-5) was measured in the NBS triple quadrupole (QQQ) tandem mass spectrometer. For P≃0.02-0.13 mTorr and E ≃ 5-60 eV (Lab) [the range of collision energies used for collisionally activated dissociation (CAD)], identical σ(E) were measured from both the rate of reactant ion decay and the rate of product ion formation. Therefore, these σ values are substantially free from kinetic interferences (i.e., no back reactions, no impurity reactions, no scattering losses, minimal fringing fields, no mass discrimination, well-defined gas target, etc.). Moreover, there is probably no significant systematic error in our measurements of the absolute σ values for N 2+· + SF6 → N2+SFx+ (x = 1-5) because the σ values we measured with this same technique for Ne +·+ Ne → Ne+Ne+·, Ar+· + Ar → Ar+Ar+·, and Ar+·+N2 → Ar+N2+· agreed well with literature values obtained with several well-established techniques.
Zusätzliches Material:
2 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/rcm.1290020207
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