Seminars Archive

Time-dependent calculations of strong field ionization and high harmonics generation

Abstract
Strong field atomic ionization with several active electrons involved is a challenging problem in which the highly nonlinear field interaction is entangled with the few-body correlated dynamics. The two-photon double-electron ionization (TPDI) of helium is the archetypal reaction of this kind. Even for this simplest many-photon many-electron process, non-perturbative treatment of the external field is essential as well as a proper account of correlation in the two-electron continuum. Neglect of either aspect of TPDI may result in a gross failure. Recently, we proposed a theoretical method based on a basis-based integration of the time-dependent Schrödinger equation with subsequent projection of the solution on a set of the field-free correlated final states [1]. This method was also used for the calculations of the strong DC field assisted atomic ionization [2,3] and the high-harmonics generation (HHG) [4] processes. In further applications, the method will be applied to atomic ionization processes on the attosecond time scale as well as the HHG from the excited and metastable atomic states. References [1] I. A. Ivanov and A. S. Kheifets. Two-photon double ionization of helium in the region of photon energies 42-50 eV. Phys. Rev. A, 75(3):033411, 2007. [2] I. A. Ivanov and A. S. Kheifets. Single-photon double ionization of negative hydrogen ions in the presence of a DC electric field. Phys. Rev. A, 75(6):062701, 2007. [3] I. A. Ivanov and A. S. Kheifets. Single-photon double ionization of helium in the presence of DC electric field. Phys. Rev. A, 74(4):042710, 2006. [4] I. A. Ivanov and A. S. Kheifets. High harmonics generation from excited states of atomic lithium. J. Phys. B, 41, 2008.