We have carried out a comprehensive theoretical and experimental study of electrom scattering from molecular nitrogen at energies below 10.0eV. In the theoretical component of thisproject we have generated differential and interal cross sections for elastic scattering and vibrational excitation in converged vibrational close-coupling calculations. In the experiments, we have measured differential 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 10eV and, in a complementary time-of-flight experiment, total cross sections at energies between 0.08 and 10.0eV. The measured angular distributins 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-N2 scattering matrix; numerical integration of the resulting extragpolated distributions yields integrated cross sections with almost no error beyond that inherent in themeasured an gular data. We find generally good agreement between the present expermental and theoretical cross section, particularly at energies near the IIg resonance near 2.39eV. In previous studies of scattering in this region, such comparisons have been made problematiocal by the difficulty of ascertaining the appropriate theoretical scattering energy. We recommend here a protocol for resolving this problem for both elastic scattering and vibrational excitation.

An unusual resonance feature of the photodetachment cross-section for the 3σu channel of F-2 observed in the early static-exchange study is confirmed by using correlated target (F2) wavefunctions determined by configuration interaction (C1). The magnitude of the cross-sections is lowered from that in earlier calculation by the potential of the correlated sarget.

A physically well behaved analytical potential of a diatomic system is constructed based on perturbation theory and a potential correction to the Murrell-Sorbie potential. Alternative formulae for rotational constants and ro-vibrational energies are suggested. An energy-consistent method is proposed for calculating accurate potential energy curves of diatomic states. Applications of this method to the electronic states X 1Σ+g, C 1Πu, a 3Σ+g, e 3Σ+u of H2, the ground state X 1Σ+g of N2, and the states X 3Σ−g, C 1Σ−u, B 3Σ−u of the O2 molecule show that the present potential agrees excellently with the known Ryderberg-Klein-Rees data or accurate configurationinteraction (CI) studies, and is better than other analytical and some CI potentials, particularly for molecular electronic excited states.

Calculations of the photodetachment ross section of F-2 in the 3σu channel are reorted in both the static-exchange and the first Born approximations. A high-energy resonance feature is found in the static-exchange result, which is evidently not associated with tunneling through an angular momentum barrier. The behavior of this feature with varying in ternuclear distance is explored, and the possible effects of channel coupling on this resonance are discussed.

Altenative expressions for photoionization cross-sections and dielectric influence functions are suggested to study the photoionization cross-sectlons of atoms in solid system. The basic picture is that the photoionization cross-section of atoms in a real system can be described as the coupling between quantum quantity (QQ) and classical quantity (CQ) parts The QQ pail represents the photoionization cross sections of an i solaled particle, while the CQ part may represent most of the important influence of the macroscopic effects (e.g.. the interactions of all surrounding polarized particles, and the dielectric property. etc.) on the photoionization cross-sections. The applications to the barium system show that tbe number-density-dependent new photoionization formula not only obtains the same cross-sections as those from the first order approximation for ideal gas. but also can generate the cross-sections for solid barium by transforming those of ideal gas of the same species using the dielectric influence function.