Utilizing a crossed electron beam and a molecular beam collision geome
try and the single particle counting technique, cross sections for the
production of positive ions by electron impact on methanol have been
measured for electron impact energies ranging from 0 to 500 eV. Appear
ance potentials for the various ionic fragments have also been obtaine
d. These potentials are compared with values calculated from the heats
of formation for methanol and for neutral and cationic products in or
der to identify the various channels of dissociation at threshold ener
gies.