Mass spectrometric determination of the ionisation cross-sections of BaO, Ba, BaF2 and BaI2 by electron impact

摘要: Abstract A Nier-type mass spectrometer coupled with a Knudsen cell was used for the ionisation cross-section measurements of Ba, BaO, BaF 2 and BaI , using appropriate internal standards known cross-sections. The vapour pressure ratio standard to investigated compound, needed calculation obtained via chemical analysis effusate. use this approach eliminated several sources uncertainties. problems concerning preferential loss fragment ions also discussed partly eliminated. results were compared predictions, usually in field high temperature spectrometry more recent model cross-sections molecules (MCM).