Use of capacitance diaphragm gauges at pressures down to 10−6 Torr

J. Phys. B: At. Mol. Opt. Phys.

et al. 2001

Absolute partial cross sections for electron-impact ionization of CF4 are reported for electron energies from threshold to 1000 eV. The product ions are mass-analysed using a time-of-flight mass spectrometer and detected with a position-sensitive detector whose output demonstrates that all product ions are collected with equal efficiency irrespective of their initial kinetic energies. Data are presented for the production of CF3+, CF2+, (CF+ + CF32+), C+, F+ and CF22+ and for the total cross section which is obtained as the sum of these partial cross sections. The overall uncertainties in the absolute cross section values are ±5% to ±8%. Data are also presented for formation of (CF+, F+) and(CF2+, F+) ion pairs. Comparison is made with prior experiments and calculations.

Section: Apparatus and Experimental Methodsmentioning

confidence: 99%

Absolute partial cross sections for electron-impact ionization of CF₄from threshold to 1000 eV

Sieglaff

Rejoub

J. Phys. B: At. Mol. Opt. Phys.

et al. 2001

“…The target number density n is obtained from measurements of the gas pressure using a capacitance diaphragm gauge. 9 The NO used in this work was obtained from the Aeriform Corporation and has a minimum specified purity of 98.5%. NO 2 was obtained from Matheson Gas Products and has a specified purity of 99.5%.…”

Section: Apparatus and Experimental Methodsmentioning

confidence: 99%

Absolute partial cross sections for electron-impact ionization of NO and NO2 from threshold to 1000 eV

The Journal of Chemical Physics

Mangan

Straub

et al. 2000

Self Cite

Absolute partial cross sections for electron-impact ionization of H 2 O and D 2 O from threshold to 1000 eV Absolute partial cross sections for electron-impact ionization of CH4 from threshold to 1000 eV Absolute partial cross sections for electron-impact ionization of nitric oxide and nitrogen dioxide are reported for electron energies from threshold to 1000 eV. The product ions are mass analyzed using a time-of-flight mass spectrometer and detected with a position-sensitive detector whose output demonstrates that all product ions are collected irrespective of their initial kinetic energy. Data are presented for the production of NO ϩ , N ϩ , O ϩ , and NO 2ϩ ions from NO; and for the production of NO 2 ϩ , NO ϩ , N ϩ , O ϩ , and (N 2ϩ ϩO 2ϩ ) ions from NO 2 . The overall uncertainty in the absolute cross section values is Ϯ5% for singly charged parent ions, while that for the fragment ions may be as large as Ϯ20%. For NO, the previously published data are generally in reasonable agreement with those presented here, although there remain some significant discrepancies with even the most recent work. No previous comprehensive study of NO 2 has apparently been reported but the experimental NO 2 ϩ cross section data that are available disagree substantially with the present measurements. The present total NO 2 cross section is, however, in excellent agreement with recent theoretical work.

Section: Apparatus and Experimental Methodsmentioning

confidence: 99%

Absolute partial cross sections for electron-impact ionization of CO from threshold to 1000 eV

Mangan¹,

J. Phys. B: At. Mol. Opt. Phys.

Stebbings

2000

Absolute partial cross sections for electron-impact ionization of CO are reported for electron energies from threshold to 1000 eV. The product ions are mass analysed using a time-offlight mass spectrometer and detected with a position-sensitive detector whose output unequivocally demonstrates that the various product ions are collected with equal efficiency irrespective of their initial kinetic energies. Data are presented for the production of CO + , C + , O + and CO 2+ , and for the total cross section which is obtained as the sum of these partial cross sections. The overall uncertainty in the absolute cross section values is ±5% for singly charged parent ions and ±6% for fragment ions. Comparison is made with prior experiments and calculations.