Electron-impact excitation collision strength Ω(nl-n'l')(3≤n≤7,4≤n'≤7) among configuration-average levels for the Ni-like Ions Pb⁵⁴⁺, Au⁵¹⁺,Ba²⁸⁺,Mo¹⁴⁺,Ge⁴⁺ have been calcuated systematically using the quasirelativitic distorted-wave methods. In addition, the collision strength in high limit have been calculated. The data for the collision strength or thermally averaged rate coefficient over the whole range of energy or temperature have been evaluated by a least-squares spline fitting procedure. As a result, the collision strength with arbitrary electron energy and rate coefficient with arbitrary temperature can be determined by ten parameters.

Following the preceding paper(Ref.[I]),an improved method is presented for calculating the integrals in electron-atom colllisions by transforming the integration contours into complex plane.This method can calculate the integrals accurately not only for cases like Ref[I],but also for the case of"nearly degenerate"which cannot be calculated by methods given in Ref[I].The caleulational accuracies have been compared and checked to be very high.

In electron-atom (or ion) collisions, it is unadvoidable to compute a large number of integrals with seriously oscillatory wavefunctions. Since direct numerical integration are very exhausted and often may fail to reach the required accuracy, analytical methods are necessary. In this paper an improved method is presented for calculating integrals with seriously osillatory in tegrands. The accuracy of phase calculation is improved for the case of wavenumber being different. The analytical expressions of integrals are given for the case of wavenumber being equal. The accury of simulation results are very satisfactory.

Cross section for the excitation of Al¹⁰⁺ ion by electron impact from ground state to 2p,3s and 3p states has been investigated with 2-state does-coupling (2cc) and 5-state close -coupling(5cc) approximations. The indirect coupling effect has been analyzed, comparing with the results of distorted wave approximation, it is found that the coupling effect is less important for 2s-2p transition, but for 2s-3s and 2s-3p transition it should be taken into account.

The problem of the slow convergence has been resolved in partial wave expansion for the excitations of electron-ion collisions, with three approximations including plane wave, coulomb Bethe and equimultiple decrease series. As an example, we have computed some important transitions of Ne-like Ge ion and made comparisons between the results obtained by three approximations. The results slow-that all the three methods are acceptable.

This paper briefly describes the theoretical deduction of the cross section of electron-ion impact excitation in Coulomb-Born approximation. The LS coupling representation of electron-ion system is used, the exchange effect is taken into account and the angular factors of collision matrix elements are treated in detail. The corresponding code-CBX(9) is programed. The situations of complex ions and incident electrons with lower energy can be computed by the code, which has wide applicability. The computational results are in well agreement with ones obtained from the other methods.