Semi-empirical estimation of ion-specific cross sections in electron ionization of molecules.

Partial ionization cross sections are the absolute yields of specific ions from an electron-molecule collision. They are necessary for modeling plasmas and determining the sensitivity of mass spectrometers, among other applications. They can be predicted semi-empirically when experimental data are available for channel-specific oscillator strengths. However, such data are seldom available because they are obtained using specialized apparatus. Here, an alternative semi-empirical method is proposed that exploits experimental data obtained using ordinary mass spectrometers, as corrected for mass discrimination. Data are presented for an incident electron energy of 70 eV.