Absolute electron impact ionization cross-sections for CF4: Three dimensional recoil-ion imaging combined with the...

Area of Science:

• Atomic and Molecular Physics
• Chemical Physics
• Plasma Science

Background:

• Accurate cross-section data for electron-impact processes are crucial for understanding and modeling plasmas and chemical reactions.
• Previous studies on electron-CF4 interactions often reported relative cross-sections or used corrections for absolute values, introducing uncertainties.
• Reliable absolute cross-section measurements are needed for various applications, including plasma etching and atmospheric chemistry.

Purpose of the Study:

• To present precise measurements of dissociative and non-dissociative cross-sections for electron impact on carbon tetrafluoride (CF4).
• To establish a reliable method for determining absolute cross-sections by minimizing experimental errors.
• To compare new findings with existing theoretical and experimental data and elucidate methodological differences.

Main Methods:

• Utilized a Recoil Ion Momentum Spectrometer (RIMS) coupled with a standard gas mixing setup for CF4 and a reference gas.
• Employed the relative flow technique (RFT) to convert relative cross-section measurements into absolute values.
• Conducted experiments at electron energies up to 1 keV, covering the range of previous investigations.

Main Results:

• Obtained absolute cross-section values for electron-impact dissociative and non-dissociative processes on CF4.
• Minimized ion collection and calibration errors through the combined RIMS and RFT approach.
• Demonstrated the reliability of the new measurement method compared to existing techniques, highlighting the impact of reduced correction terms.

Conclusions:

• The RIMS and RFT combination provides a reliable method for accurate absolute cross-section measurements of electron-CF4 interactions.
• The new data offer improved accuracy for modeling and understanding processes involving CF4 in various environments.
• Understanding the impact of reducing correction terms is vital for advancing experimental techniques in electron-molecule scattering studies.