arXiv physics/07012952007-01-25physics.atom-ph

Quasistatic limit of the strong-field approximation describing atoms and molecules in intense laser fields

Yulian V. Vanne Alejandro Saenz

备注：: 12 pages, 6 figures

英文摘要：

The quasistatic limit of the velocity-gauge strong-field approximation describing the ionization rate of atomic or molecular systems exposed to linear polarized laser fields is derived. It is shown that in the low-frequency limit the ionization rate is proportional to the laser frequency, if a Coulombic long-range interaction is present. An expression for the corresponding proportionality coefficient is given. Since neither the saddle-point approximation nor the one of a small kinetic momentum is used in the derivation, the obtained expression represents the exact asymptotic limit. This result is used to propose a Coulomb correction factor. Finally, the applicability of the found asymptotic expression for non-vanishing laser frequencies is investigated.

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