Fit of the different species contributing to the mass spectra obtained after 64 min VUV photolysis of CH₃OH at 20 K. The thin bars at different masses represent the integrated area of all individual mass peaks. The mass spectra are fitted simultaneously for two different electron-impact ionisation energies (35 eV, A+B and 70 eV, C+D). The fragmentation patterns of all individual species have been measured in reference experiments; see Table 3 for electron-impact ionisation cross sections.