Initial state distortion and final state correlation effects in (e, 2e) processes on hydrogen

The triple differential cross sections (TDCS) for electron impact ionization of H in coplanar asymmetric geometry at low and intermediate energies are calculated by using the BBK and the DWBA models, and the results are compared with the experimental measurements. The initial state distortion effect and the final state correlation effect on the TDCS are investigated and the physics behind the final state correlation effect is revealed. It has been found that the initial state distortion effect is weak such that it can be ignored at incident energies above 150 eV. On the other hand, the final state correlation effect is always important. With the final state correlation effect taken into account, the positions of both the binary peak and the recoil peak shift to larger angles, and the height of binary peak is suppressed and the shape of recoil peak is reproduced in better agreement with experiment. (authors)