The Emission Spectra of Hydrogen Atoms Produced from Methanol by Electron Impact

The emission spectra of several fragmental species, especially of hydrogen atoms, produced by the electron impact (energy:240 eV) of gaseous methanol and deuteromethanols have been investigated. The intensity ratios of the Balmer-β lines of the H and D atoms are ca. 2.9:1 for CH3OD and ca. 1:1.8 for CD3OH, indicating that the excited hydrogen atoms result from the O–H bond scission, as well as from the C–H bond scission, of the parent methanol molecules. The ratio of the scission probability of a C–H bond to that of the O–H bond is calculated to be 0.8, taking into account the correction of the isotope effect. It was concluded that the excited hydrogen atoms are produced by the primary process of fragmentation via a superexcited species.