Abstract
The mean energy expended per ion pair, omega , for electrons in molecular nitrogen has been obtained by solving the Fowler equation in the energy range from the ionisation threshold up to 1 keV. The same set of collisional cross sections has also been employed to obtain omega in the continuous slowing-down approximation (CSDA). It is found that Fowler-equation values are always smaller than CSDA values. However, the difference between the two sets of values decreases with increasing incident energy. The results are in good agreement with the available experiment data.