Abstract
The electron-phonon coincidence technique was applied to the measurement of lifetimes in N2 and H2. In this method the inelastically scattered electrons are analysed and used to select the upper state of interest, thus eliminating the systematic errors due to cascading and the spectral overlap of different band systems. The lifetimes of the first three vibrational levels of the C3 Pi u state of N2 were found to be 35.6+or-0.5, 34.9+or-1.8 and 34.5+or-2.3 ns, and those of the first two vibrational levels of the a 3 Sigma g+ state of H2 were found to be 11.0+or-0.42 and 10.6+or-0.6 ns.