Low Energy Electron Collision Cross Sections for Methane

Measurements of the drift velocity vdr and the ratio of the lateral diffusion coefficient to mobility D1/p. have been made in pure methane at 293 K. Measurements of vdr and D1/p. were made for values of E IN (the electric field strength divided by the number density) ranging from 0�03 to 14 Td and 0�02 to 12 Td respectively (1 Td == 10-21 Vm2). The estimated accuracy of the results is � 1 % for vdr and �2% for Dli p.. The data have been analysed by means of a multiterm solution of the Boltzmann equation to provide a set of low energy electron collision cross sections consistent with the transport data.