The (e, 2e) triple-differential cross sections of Ag + (4p, 4s) are calculated based on the three-body distorted-wave Born approximation considering post-collision interaction in coplanar symmetric geometry. The energy of the outgoing electron is set to be 50, 70, 100, 200, 300, 500, 700, and 1000 eV, and the intensity and splitting of forward and backward peaks are discussed in detail. Some new structures are observed around 15 • and 85 • for 4p and 4s orbitals. Structures in triple-differential cross sections at 15 • are reported for the first time. A double-binary collision is proposed to explain the formation of such structures. The structures at 85 • are also considered as the result of one kind of double-binary collision.

The (e, 2e) triple differential cross sections of 2s orbitals of neon and neonic ions (Z = 11-14) are calculated using a distorted-wave Born approximation under coplanar asymmetric geometry. The calculated results show that, with the increase in the nuclear charge number Z, the amplitude of triple differential cross sections decreases. The angle difference between the binary peak position and the direction of momentum transfer gradually increases with the increase in the nuclear charge Z, and a new structure appears at an ejected angle 90 • < θ 2 < 120 • . Three kinds of collision processes are proposed to illustrate the formation mechanism of such collision peaks.

The (e, 2e) triple differential cross sections for He(1s2)，Ar(3p6)and Ar(2p6)have been calculated using the modified distorted wave Born approximation (DWBA) in coplanar asymmetric geometry. The kinematics employs large energy transfer and is close to minimum momentum transfer. The theoretical results have been compared with those of the experiment, the Brauner, Briggs and Klar (BBK) method and the standard DWBA calculation. It is shown that the polarization and post-collisional interaction effects are very important in coplanar asymmetric (e, 2e)reaction with special kinematics for He(1s2), Ar(3p6) and Ar(2p6).

The (e, 2e) triple differential cross sections (TDCSs) of Ar (3s) are calculated by using distorted-wave Born approximation under coplanar asymmetric geometry. The incident electron energy is 113.5 eV, and the scattering electron angle θ 1 is −15 • . The ejected electron energy is set at 10 eV, 7.5 eV, 5 eV, and 2 eV, respectively. The polarization effects have been discussed and the polarization potential V pol changing from a second-order to a fourth-order term has been analyzed. Our calculated TDCSs have been compared with reported experimental and theoretical results, and the calculated TDCSs of polarization potential up to the fourth order could give a good fit with experimental results in the binary region, but fail to predict the correct recoil-to-binary ratio in most cases.