Instrument-independent cad spectral databases: absolute cross-section measurements in QQQ instruments

Abstract

The energy dependence of the cross section, cr(E), for the symmetric (resonant) charge transfer reaction Ar+(Ar,Ar)Ar+ was measured in our triple quadrupole (QQQ) tandem mass spectrometer. lOur cr(E), for P=0. [the range of collision energies

Kinetic-energy measurement of a neutral stream extracted from Ar electron cyclotron resonance plasma

“…As the pressure increases from 1.4 to 2.9ϫ10 Ϫ4 Torr, the mean-free path for charge-exchange collision is estimated to decrease from about 28 to 13.5 cm. 15 This indicates that at higher pressure, there are more collisions at the near side to the source than at far side, i.e., the generation of the lower-energy neutrals is larger at higher pressure. Moreover, elastic scattering and second chargeexchange collisions are apt to occur at the higher pressure and they also produce lower-energy neutrals.…”

Instrument‐independent tandem mass spectrometry database for XQQ instruments: The dynamical prerequisites

“…1-3. [42][43][44][45] Under such conditions one observes a poorly resolved MS/MS spectrum in Q3." Hence, it would not be possible to make a dynamically-correct determination of the relative abundance of progeny ions which are separated by only a few amu.…”

Absolute cross-section measurements in XQQ instruments - The NBS round robin

“…Ar'(Ar,Ar)Ar~ [10] to determine the target thickness [B]L }, followed by ii) the experiment associated with figure 1(a) of [9].…”

“…Moreover, real-time trace analysis often involves unknown transient species (e.g., reactive environmental pollutants and/or products of their photooxidation). Characterization of such species would be facilitated if one could do spectral matching against a generic, instrument-independent MS/MS CAD spectral database comprised of known ionic substructures (see [10,11]). …”

“…This ±+10% error estimate is consistent with our observations that deviations from linearity in In W vs P plots occurred only when single-collision conditions were exceeded. So single-collision conditions must be used if one is to develop and use a generic, instrument-independent MS/MS CAD spectral database [10,11].…”