We have carried out a comprehensive theoretical and experimental study of electron scattering from molecular nitrogen at energies below 10.0 eV. In the theoretical component of this project we have generated differential and integral cross sections for elastic scattering and vibrational excitation in converged vibrational close-coupling calculations. In the experiments, we have measured dift'erential cross sections for these processes at scattering angles from 20' to 130 in a crossed-beam experiment at a large number of energies between 0.55 and 10 eV and, in a complementary time-of-Right experiment, total cross sections at energies between 0.08 and 10.0 eV. The measured angular distributions have been extrapolated to 0 and 180 using a procedure based on a nonlinear least-squares fit constrained by known physical properties of the e-Nz scattering matrix; numerical integration of the resulting extrapolated distributions yields integrated cross sections with almost no error beyond that inherent in the measured angular data. We find generally good agreement between the present experimental and theoretical cross section, particularly at energies near the H~r esonance near 2.39 eV. In previous studies of scattering in this region, such comparisons have been made problematical by the difhculty of ascertaining the appropriate theoretical scattering energy. We recommend here a protocol for resolving this problem for both elastic scattering and vibrational excitation.PACS number(s): 34.80.6s

Absolute cross sections for elastic scattering and rovibrational excitation have been measured with a crossed beam spectrometer and calculated, utilizing the R-matrix formalism, for incident electron energies between 1.0 and 30 eV. Particular emphasis is placed on the comparison between experiment and theory in the region below 5 eV where the cross sections are enhanced by a strong 2 shape resonance.

Absolute differential (12 • -130 • ) cross sections for low energy (1-10 eV) electron scattering from argon have been measured on two separate and different spectrometers using the relative flow technique. The data have also been analysed using phaseshift techniques. Comparisons are made between the present cross sections and phaseshifts and similar data from previous experiments and theory. The results are particularly encouraging, with recent experiments and scattering theories being in good general agreement.

Absolute differential cross sections for elastic scattering and vibrational excitation of have been measured at incident energies between 0.6 and 5.4 eV. These cross sections have also been extrapolated and integrated in order to derive integral and momentum transfer cross sections which are compared with the results of previous single-collision and electron swarm experiments. Elastic differential cross sections have also been calculated using a body-fixed (BF), single-centre expansion (SCE) for the close-coupled (CC) equations. There is excellent agreement between the present data and the most recent elastic scattering results of Boesten and Tanaka, but substantial discrepancies between these two data sets and several previous measurements. There is also excellent agreement at most energies between the present measured and calculated elastic cross sections.