Mechanisms underlying strong-field double ionization of argon dimers

Manschwetus, Bastian; Rottke, H.; Steinmeyer, G.; Foucar, L.; Czasch, A.; Schmidt‐Böcking, H.; Sandner, W.

doi:10.1103/physreva.82.013413

Cited by 58 publications

(43 citation statements)

References 30 publications

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“…The first scenario is a two-site tunnel-ionization which is accompanied by excitation to a potential energy curve substantially steeper than 1/R. Alternatively our data are also consistent with a laser-induced charge transfer mechanism put forward in [36].…”

Section: Discussionsupporting

confidence: 88%

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Double-ionization mechanisms of the argon dimer in intense laser fields

et al. 2010

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We have measured the two-site double ionization of argon dimers by ultrashort laser pulses leading to fragmentation into two singly charged argon ions. Contrary to the expectations from a pure Coulomb explosion following rapid removal of one electron from each of the atoms, we find three distinct peaks in the kinetic energy release (KER) distribution. By measuring the angular distribution of the fragment ions and the vector momentum of one of the emitted electrons for circular and linear laser polarization, we are able to unravel the ionization mechanisms leading to the three features in the KER. The most abundant one results from tunnel ionization at one site followed by charge-enhanced tunnel ionization of the second atom. The second mechanism, which leads to a higher KER we identify as sequential tunnel ionization of both atoms accompanied by excitation. The third mechanism is present with linearly polarized light only. It is most likely a frustrated triple ionization, where the third electron does not escape but is trapped in a Rydberg state.

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Section: Discussionsupporting

confidence: 88%

“…As for the rescattering mechanism, no orientation dependence would be expected. Manschwetus and coworkers [36] suggest a process of laser induced charge transfer in the dimer which produces a one-site double excited state which than decays via RCT giving rise to peak (b). This scenario is consistent with our data.…”

Section: B Peak (B)mentioning

confidence: 99%

Double-ionization mechanisms of the argon dimer in intense laser fields

et al. 2010

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“…[13,14] shows features of both atoms and molecules * doerner@atom.uni-frankfurt.de and has attracted growing interest for its interaction with ions [15], synchrotron radiation [16] and strong laser fields [17,18]. Rare-gas dimers with their extraordinary large internuclear distance and the absence of real delocalized molecular orbitals have a unique combination of atomic structure and energetics with an additional axis as the only molecular feature.…”

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confidence: 99%

“…Exposed to the intense probe pulse, the neutral dimers are multiply ionized by simultaneously absorbing several photons, leading to direct CE of the charged nuclei. The production of Ar + + Ar + by linearly polarized light has been shown [17,18] to proceed through three different double ionization mechanisms leading to three different peaks in the kinetic energy release (KER) distribution at 3.8, 5.3 and 7.3 eV [see Fig. 3(b)].…”

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confidence: 99%

“…The potential energy curves of these states are in the relevant region very close to the one for Ar 2+ + Ar + . It has been speculated [17,18] that the intermediate peak at 5.3 eV is due to double ionization with excitation to an excited state of the Ar 2 2+ which is steeper than the ground state. Figure 3(a) shows the alignment dependence of these three KER peaks by comparing the ionization rate of the dimers when the time delay of the probe pulse is tuned to match the alignment and anti-alignment revivals of the pre-aligned Ar 2 [as labeled with A and B in Fig.…”

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Nonadiabatic alignment of van der Waals--force-bound argon dimers by femtosecond laser pulses

Vredenborg

Ulrich

et al. 2011

Phys. Rev. A

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We demonstrated that the weak van der Waals-force-bound argon dimer can be nonadiabatically aligned by nonresonant femtosecond laser pulses, showing periodic alignment and anti-alignment revivals after the extinction of the laser pulse. Based on the measured nonadiabatic alignment trace, the rotational constant of the argon dimer ground state is determined to be B 0 = 0.05756 ± 0.00004 cm −1 . Noticeable alignment dependence of frustrated tunneling ionization and bond-softening induced dissociation of the argon dimer are observed. PACS number(s): 32.80. Rm, 33.15.Bh, 42.65.Re Moderately intense laser pulses can efficiently align molecules, i.e., confine the molecular axes to axes fixed in space. In the nonadiabatic limit where the pulse duration is much smaller than the inherent rotational period a rotational wave packet is induced in each molecule by stimulated Raman transitions. The quantum beats between the states leads to field-free alignment and anti-alignment revivals of the nonadiabatically aligned molecular ensemble after the laser pulse [1]. In the past, the nonadiabatic molecular alignment has attracted a lot of interest for its extensive range of applications such as tomographic imaging of molecular orbitals [2], laser induced electron diffraction [3], quantum interference in high-harmonic generation [4], and ultrashort laser pulse manipulation and characterization [5,6]. The degree of molecular alignment could be increased by using a train of sequential pulses [7] or shaped ultrashort pulses [8]. Threedimensional alignment of complex molecules were created by using elliptically polarized laser pulses [9,10]. Recently, adiabatic alignments of rare-gas dimers with nanosecond pulses were demonstrated to characterize the polarizability anisotropies [11]. Nonadiabatic alignment of molecular cluster was achieved to extract the rotational constant [12], which requires a molecular cluster to possess a long-lived excited state and thus cannot be applied to the rare-gas dimer.In this Rapid Communication, we demonstrate that the weak van der Waals-force-bound rare-gas argon dimer (Ar 2 ) can be nonadiabatically aligned by using nonresonant femtosecond laser pulses. The field-free alignment and antialignment revival structures were measured up to ∼1 ns after the nonadiabatic excitation of the laser pulse without noticeable decay of alignment contrast and change of the shape, indicating a well-preserved coherence of the rotational wave packets. We extracted the ground state rotational constant from the nonadiabatic alignment trace and determine it to be B 0 = 0.05756 ± 0.00004 cm −1 . The alignment dependence of the bond-softening induced dissociation and frustrated tunneling ionization of argon dimer are observed.The Ar 2 bound by the weak van der Waals force (∼12.3 meV or 99.2 cm −1 ) at a large internuclear distance (R e ∼7.1 a.u.) [13,14] shows features of both atoms and molecules * doerner@atom.uni-frankfurt.de and has attracted growing interest for its interaction with ions [15], synchrotron radiation [16...

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Strong-Field Induced Atomic Excitation and Kinematics

Eichmann

2015

Ultrafast Dynamics Driven by Intense Light Pulses

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Mechanisms underlying strong-field double ionization of argon dimers

Cited by 58 publications

References 30 publications

Double-ionization mechanisms of the argon dimer in intense laser fields

Double-ionization mechanisms of the argon dimer in intense laser fields

Nonadiabatic alignment of van der Waals--force-bound argon dimers by femtosecond laser pulses

Strong-Field Induced Atomic Excitation and Kinematics

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