PUB - Publikationen an der Universität Bielefeld

Unexpectedly large probability of laser-induced nonsequential double ionization of He had been observed experimentally. We have recently suggested a mechanism of energy sharing via e-e correlation, based on the leading Feynman diagram of the process, obtained from the Intense-Field Many-Body S-Matrix Theory. In this paper we derive a simple model formula for the total rate of the process by extending this diagram to all orders and summing them approximately. Comparisons of the predictions of the model with the data in He at 780 nm over a wide range of intensity by Walker et al. (1994) show a remarkably good agreement for both single and double ionization rates per atom. It is found that this is due to the simultaneous influence of intermediate rescattering, field-induced energy boosting, and e-e correlation during the process.