LOW-ENERGY-ELECTRON SCATTERING FROM METHANE

Absolute differential cross sections for elastic scattering and vibrat ional excitation (nu(2.4), nu(1.3)) of CH4 have been measured at incid ent energies between 0.6 and 5.4 eV. These cross sections have also be en extrapolated and integrated in order to derive integral and momentu m transfer cross sections which are compared with the results of previ ous single-collision and electron swarm experiments. Elastic different ial cross sections have also been calculated using a body-fixed (BF), single-centre expansion (SCE) for the close-coupled (CC) equations. Th ere is excellent agreement between the present data and the most recen t elastic scattering results of Boesten and Tanaka, but substantial di screpancies between these two data sets and several previous measureme nts. There is also excellent agreement at most energies between the pr esent measured and calculated elastic cross sections.