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.

Theoretical studies of low-energy electron-silane scattering are reported in whichtarget polarization is included by using an ab intion optical potential. These calculations employ the complex Kohn scattering method and were underkaken both at the static-exchange level and with target polarizatin. Aploarized wirtual-orbital method, which was introduced in our earlier study of electron-methane scattering, was also employedin this study co generate a compact description of the closed channels included in the optical potential. Differential, integral, and momentum-transfer cross sections a Ramsaurer-Townsend minimum at 0.3eV and a broad d-wave shape resonance at 3.0eV. Excellent agreement is found between our polarized Kohn results and the recent experimental resultsof Wan, Moore, and Tosssel[J. Chem. Phys. 91, 7340 (1989)].

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.

The calculation of electron-molecule cross sections at scattering energies well below 0.1 eV using conventional algorithms for solving the Schr

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.

The energy-consistent method for calculating accurate potential energy curves of diatomic states is proposed based on a modified Murrel-Sorbie (MS) potential. The accurate vibrational eigenvahues and eigenfunctions for the physical potentials of stable diatomic moleculegs are obtained using this method. The artefact of the MS potential shown in the Huxley-Murrell formulation dissappearss in the present method.

The vibrational excitation differntial coross sections (DCS) of low-energy eleeltron-N2 soattering are studied using vibrational elm-coupling (VCC) scattering method and quantum scattering potentials which include starie, exchange, and polarizatinn contributions hased on ab initio calculation. By including the contributions of 11 partial waves (up to l=21), 15 vibrational states, and 16 molecular symmetries (up to A=7), the converged vibrational excitation (0→2, 0→3, 0→4) DCSs. the scattering resonance, and the vibrational multi-peak structtore agree well with experimenial results.

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.

An analytical five-term expansion potential is suggested to improve the recently proposed energy consistent method (ECM) potential based on a three-term expansion [Weiguo Sun, Mol. Phys. 92, 105 (1997) and Weiguo Sun and Hao Feng, J. Phys. B: At., Mol. Opt. Phys. 32, 5109 (1999)]. Applications of the new ECM to the electronic excited state 31Ⅱ of NaK, the excited state 23Σ+g of Na2, and the excited states 31Σ+u 1 and 31Ⅱu of K2 molecules show that the new ECM potential not only agrees excellently with the known Rydberg-Klein-Rees (RKR) data or accurate configuration interaction (CI) studies but also gives the potential data at the molecular asymptote and the dissociation region where experimental and quantum mechanical studies may have difficulties. The new ECM can correct the artifact which appeared in the three-term expansion potentials of both the previous ECM and the Huxley-Murrell-Sorbie (HMS) potential and can describe some states to which both the previous ECM and the HMS fail.

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.