Creation of multihole molecular wave packets via strong-field ionization

Pulse-shape-dependent strong-field ionization viewed with velocity-map imaging

“…This suggests that there are some subtleties in the ionization process that are not captured by our calculations, which treat the coupling between the neutral and ionic states in a simple manner. This is consistent with our earlier measurements on CH 2 I 2 , which showed asymmetric chirp dependence in the ionization to different cationic states [10]. We also note that our interpretation of the experimental data assumes that the KER distributions associated with the various populations do not change significantly with laser pulse shape.…”

“…For example, the role of electron correlation and Koopmans correlations between initial neutral states and final cationic states is still not understood [7], with new calculations aiming to address this [8]. Our focus here is on the superposition of electronic states of the molecular cation generated by ionization in a short, intense laser pulse [9][10][11][12][13]. While such superpositions have been discussed in the context of high harmonic generation [2,[14][15][16], we make use of velocity map imaging and ab initio electronic structure calculations to characterize the superposition of cationic states or "electron holes" generated via strong field ionization.…”

“…In an earlier publication we used pump-probe spectroscopy with a shaped pump pulse to demonstrate the superposition of several bound cationic states in CH 2 I 2 [10]. In this article we focus on dissociative electronic states of CH 2 BrI + that result in the breaking of the C-I bond in the cation, leading to the production of CH 2 Br + .…”

Electron-ion correlations in strong-field molecular ionization with shaped ultrafast laser pulses

“…For small polyatomic molecules the ionization potentials for the first few ionic continua can be closely spaced, i.e., within a few percent of the first ionization potential or less than 1 eV, with a first ionization potential of about 10 eV. In such a case the ionization rates to these states can be comparable [8][9][10][11] and strong-field ionization leaves the molecule in a superposition of several ionic states.…”

“…Earlier work on CH 2 I 2 demonstrated the generation of a multihole electronic wave packet via strong-field ionization, and further demonstrated control over the spectral content of the wave packet via the spectral phase (pulse shape) of the ionization pulse [9]. Here we measure the photoelectron spectrum and time-of-flight mass spectrum (TOFMS) for ions as a function of pulse shape, and correlate the energy-resolved photonelectron yield with the mass-resolved ion yield.…”