TY - JOUR
T1 - Electron impact ionization-excitation and double-ionization dynamics of He at large momentum transfer
AU - Watanabe, N.
AU - Takahashi, M.
N1 - Funding Information:
The authors are indebted to Dr. Darryl Jones at the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University for his careful reading of the present manuscript. This research was partially supported by the Ministry of Education, Culture, Sports, Science and Technology, Grant-in-Aids for Scientific Research (A) (No. 16205006) and for Scientific Research (S) (No. 20225001).
PY - 2009
Y1 - 2009
N2 - We report a collision dynamics study on electron-impact ionization-excitation and double-ionization of He at large momentum transfer. The symmetric noncoplanar (e,2e) and (e,3-1e) cross sections have been measured for transitions to the He+ n=2 excited state and He 2+doubly ionized state at impact energies of 1.2, 2.1, and 4.3 keV. An investigation of impact energy dependence of the cross sections provides definite evidence that noticeable higher-order effects are involved even at the rather high impact energies used. It has been found that second Born approximation calculations satisfactorily account for the experimental results, indicating that the second-order two-step mechanisms play crucial roles in the ionization-excitation and double-ionization processes under the kinematical conditions considered here.
AB - We report a collision dynamics study on electron-impact ionization-excitation and double-ionization of He at large momentum transfer. The symmetric noncoplanar (e,2e) and (e,3-1e) cross sections have been measured for transitions to the He+ n=2 excited state and He 2+doubly ionized state at impact energies of 1.2, 2.1, and 4.3 keV. An investigation of impact energy dependence of the cross sections provides definite evidence that noticeable higher-order effects are involved even at the rather high impact energies used. It has been found that second Born approximation calculations satisfactorily account for the experimental results, indicating that the second-order two-step mechanisms play crucial roles in the ionization-excitation and double-ionization processes under the kinematical conditions considered here.
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U2 - 10.1088/1742-6596/194/1/012018
DO - 10.1088/1742-6596/194/1/012018
M3 - Article
AN - SCOPUS:74549168431
VL - 194
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
SN - 1742-6588
M1 - 012018
ER -