Discussion of the role of many-electron motions in multiphoton ionization and excitation.

摘要

The character of many-electron interactions in atoms is examined in relation to a possible role for these couplings in multiphoton processes. It is found that they provide a natural mechanism which can produce both (1) anomalously rapid rates of multiphoton ionization and (2) the direct production of electronically excited ionic species. Furthermore, it is determined that these two phenomena should be strongly correlated. On this basis, the experimental data concerning multiphoton ionization and the generation of fluorescence give evidence for a significant role for two-electron amplitudes in the heavy rare gases. For subpicosecond irradiation at 248 nm, the data indicate that the multi-electron processes become important above an intensity of (approximately) 10 (sup 14) W cm(sup (minus)2), particularly for xenon. The trend exhibited by these findings suggests that multi-electron processes will become increasingly prominent at intensities above (approximately) 10(sup 16) W cm(sup (minus)2).