Electron impact ionization of atomic hydrogen

Triply differential (e,2e) cross sections for He from threshold to 50 eV above

“…10 On the other hand, the TDCS's for the 012 = IT case given by calculations using the effective-charge approximation [2,10,[12][13][14]171 are independent of the excess energy in the Ex + 0 limit. This threshold behavior can be verified by analyzing the wave functions used in such calculations.…”

“…Recently we have presented distorted-wave calculations of the triply differential cross sections for electron impact ionization of H, He, Ne, Ar, Kr, Xe, Li, and Mg for final-state electrons departing in opposite directions (€Il2 = n) and sharing between 0.5 eV and 4 eV excess energy (Ex) [14]. The results for H and the rare gases were shown [1,2] to agree well with the available relative experimental measurements [5-81. In particular, they provided an interpretation of the observed target dependence of the electron angular distributions for H and He targets [6] in terms of short-range effects on the s-wave phase shifts of both incident and final-state continuum electrons [I-21.…”

Absolute Triply Differential (e,2e) Cross Section Measurements for H with Comparison to Theory

“…0 in the WPR theory owing to the predicted rapid narrowing of the width of the distribution with respect to u 12 in the region of u 12 p. The DPW results, however, which employ an effective screening approximation [23][24][25], are independent of E ex as E ex ! 0.…”

“…The final-state wave function C 2 f is also an expansion in independent-electron states for each of the two continuum electrons, in which their orbital and spin angular momenta are coupled to partial waves characterized by L and S, which are the total orbital and spin angular momenta of the system. The major approximation to C 2 f is the replacement of the exact Coulomb interaction between the two continuum electrons by a variationally determined screening potential [23][24][25]. The DPW approach thus treats distortion, nonlocal exchange interactions, both singlet and triplet partial waves, and mutual screening interactions using effective charges which satisfy proper asymptotic boundary conditions.…”

Absolute triply differential (e,2e) cross sections for He in the intermediate energy region with comparison to theory

“…However, we have ignored such interchannel coupling and treat the channels designated by L and S as uncoupled. The major approximation to Ψ f -in our calculation is our replacement of the exact Coulomb interaction between the two continuum electrons by a variationally determined screening potential [20][21][22]. Further details on the DPW approach are presented in [4,23].…”