Electron collisions with oriented and aligned molecules - numerical results for carbon monoxide and cyclopropane

General expressions are derived for the cross section for scattering from oriented or aligned molecules. The results apply to elastic, inelastic and reactive collisions. It is shown that the essential information on the dynamics is contained in a set of parameters, the 'steric factors'. The consistent use of these factors allows a coherent and unified discussion of many different processes. Results of numerical R-matrix calculations are presented for elastic electron collisions with carbon monoxide (CO] and cyclopropane (C3H6) at an incident electron energy of E = 10 eV. The calculations show huge steric effects for collisions with cyclopropane. The results are used to interpret the steric factors and to illuminate their geometrical significance.