A deconvolution method for electron energy loss spectrum of diatomic molecules is proposed.Fitted energy positions are locked on accurate spectroscopic data.Calculated Franck-Condon factors are adjusted by a quadratic function.Precision requirement for Franck-Condon factors is reduced.Undermined parameters in deconvolution procedure are reduced dramatically.Precision of fitted results is improved. Optimized algorithm in fitting procedure avoids a lot of integral calculations.The program is used to deconvolve electron energy loss spectrum of H_2.Vibrationally resolved optical oscillator strengths are determined.The results agree well with previous experimental and theoretical studies.

The non-relativistic transition T-matrix element for electron impact ionization of H-like has been calculated with starting from the formulation of Brauner,Briggs and Klar.The final state wavefunction involving three appropriate confluent hypergeometric functions considers all three two-body interactions on an equal footing and satisfies the proper Coulomb boundary conditions.The long range Coulomb interaction occurring in the initial channel has been taken into account properly.The T-matrix element,including four confluent hypergeometric functions,has been reduced to a three-dimensional integral in real space.The results are of use in a wide class of scattering problems.

The triple differential cross sections (TDCS) in coplanar equal energy sharing and fixed relative angle geometry for electron impact ionization of He⁺ are calculated (by using a modified BBK model) at incident electron energies of 58.4,68,81.6,108.8 and 174.4 eV.Dominant ionization mechanisms are identified and the contributions of different scattering amplitudes are discussed.It concludes that Coulomb interaction in the initial channel,exchange effects,correlation and the coherence between electron electron and electron nucleus scattering are all important at these energies.

A general method to calculate the triple differential cross sections(TDCS) for electron impact ionization of hydrogen atom,hydrogenicion He⁺, helium atom and helium-like ion Li⁺is given by generalizing the theoretical framework developed by Brauner et al. The present TDCS results of H, He⁺, He and Li⁺are compared with those of other theoretical models and/or experiment, and good agreements have been found.