Multiphoton ionization of negative ions in the presence of a dc FIELD. Application to Li−

Nicolaides, Cleanthes A.; Mercouris, Theodoros

doi:10.1016/s0009-2614(89)87452-4

Cited by 51 publications

(41 citation statements)

References 32 publications

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“…Subsequent experimental observations [37] of electric-fieldinduced resonances in the photodetachment spectrum of H − induced a resurgence of activity on primarily single-photon detachment processes in the presence of a weak external electric field [38][39][40][41][42][43][44][45][46]. More recently, theorists have returned to the investigation of static-field effects on single-photon and multiphoton detachment processes (for the case in which the electric field can no longer be regarded as a weak perturbation) in order to provide detailed predictions which experiment may be capable of testing [47][48][49][50][51][52]. In what follows, we discuss briefly some of these works.…”

Section: A Brief Historical Survey Of Static Electric Field Effects Omentioning

confidence: 99%

“…Nicolaides and Mercouris [47] treated all final-state interactions in principle exactly (but completely numerically) for the case of photodetachment of Li − and H − . However, for weak fields their results only confirmed results of simpler theoretical calculations as well as the experimental measurements for H − photodetachment [37].…”

Section: A Brief Historical Survey Of Static Electric Field Effects Omentioning

confidence: 99%

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Interaction of laser radiation with a negative ion in the presence of a strong static electric field

Manakov

Frolov

Starace

et al. 2000

J. Phys. B: At. Mol. Opt. Phys.

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Abstract. This paper provides a general theoretical description of a weakly bound atomic system (a negative ion) interacting simultaneously with two (generally strong) fields, a static electric field and a monochromatic laser field having an arbitrary elliptical polarization. The zerorange δ-potential is used to model the interaction of a bound electron in a negative ion as well as the interaction of a detached electron with the residual atom. Our treatment combines the quasistationary (complex energy) and quasienergy (Floquet) approaches. This quasistationary, quasienergy state (QQES) formalism is the most appropriate one for analysing a decaying quantum system under the influence of a periodic external perturbation. Existing QQES theory is reviewed and some new results are discussed: the Hellmann-Feynman theorem and the normalization procedure for QQES, and the definition of the dipole moment and the dynamic polarizability for a decaying atomic system (in strong static electric and/or laser fields). These results are illustrated using analytical formulae obtained from an exact solution of the QQES problem for a δ-model potential in two strong fields. Finally, from the imaginary part of the dynamic polarizability we obtain analytic results (to first order in the laser-field intensity) for the photodetachment cross section. Our results are then compared with those of previous theoretical studies.

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Section: A Brief Historical Survey Of Static Electric Field Effects Omentioning

confidence: 99%

Section: A Brief Historical Survey Of Static Electric Field Effects Omentioning

confidence: 99%

Interaction of laser radiation with a negative ion in the presence of a strong static electric field

Manakov

Frolov

Starace

et al. 2000

J. Phys. B: At. Mol. Opt. Phys.

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“…In fact, the same system was used by us a few years ago for the time-independent, many-electron many-photon computations of multiphoton detachment [15], which demonstrated distinct features due to electron-structure characteristics in initial and final states.…”

Section: Introductionmentioning

confidence: 99%

Computation of strong-field multiphoton processes in polyelectronic atoms: State-specific method and applications to H andLi−

et al. 1994

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The problem of integrating the time-dependent Schrodinger equation (TDSE) describing the interaction of a polyelectronic atom with a laser pulse is treated by expanding the time-dependent wave function %(r, t) in terms of wave functions 4"E computed for discrete, autoionizing, and scattering states separately. The TDSE is transformed into a system of coupled first-order differential equations with time-dependent coeScients, whose number (in the thousands), necessary for convergence to be reliable, depends mainly on the degree of the contribution of the continuous spectrum, as a function of the frequency and strength of the field. This approach allows the systematic incorporation of the significant electronic structure, electron correlation, and spectral characteristics of each N-electron system under investigation. Furthermore, since the free-electron function is computed numerically in the polarized core potential of the remaining (N -1)-electron atom, properties such as the angular distribution and partial above-threshold ionization (ATI) of the photoelectron are directly computable. We present results from the application of our methods to H and Li . For the applications to H, which served as testing grounds for the method, the state-specific wave functions for discrete and continuum states were obtained numerically, for n and I up to 12 and 5, respectively, and for positive energies up to a= 34 eV with I up to 6. When comparisons with other time-independent and time-dependent results are possible, very good agreement is observed. On the other hand, our calculations do not confirm recent experimental results on absolute ionization rates for laser pulses of 248 nm. For Li, our results on ATI for photon energy tie=1.36 eV demonstrate the effects of initial-state electron correlation and of final-state fieldinduced coupling of open channels (the Li 1s 2s Sand 1s 2p P'), as a function of field intensity.

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“…Such a choice is particularly advantageous when theory is applied to complex atomic systems with more than one target electron. Such approach within the context of the complex rotation method has been used by Mercouris and Nicolaides [21] and Nicolaides and Mercouris [22]. Description of the quantum mechanical evolution of an atom coupled to a laser field is also possible in the framework of this method [23].…”

Section: Introductionmentioning

confidence: 99%

Lippmann-Schwinger description of multiphoton ionization

Ivanov

Kheifets

2005

Phys. Rev. A

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We outline a formalism and develop a computational procedure to treat the process of multiphoton ionization (MPI) of atomic targets in strong laser fields. We treat the MPI process nonperturbatively as a decay phenomenon by solving a coupled set of the integral Lippmann-Schwinger equations. As basic building blocks of the theory we use a complete set of field-free atomic states, discrete and continuous. This approach should enable us to provide both the total and differential cross-sections of MPI of atoms with one or two electrons. As an illustration, we apply the proposed procedure to a simple model of MPI from a square well potential and to the hydrogen atom.

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Multiphoton ionization of negative ions in the presence of a dc FIELD. Application to Li−

Cited by 51 publications

References 32 publications

Interaction of laser radiation with a negative ion in the presence of a strong static electric field

Interaction of laser radiation with a negative ion in the presence of a strong static electric field

Computation of strong-field multiphoton processes in polyelectronic atoms: State-specific method and applications to H andLi−

Lippmann-Schwinger description of multiphoton ionization

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