Double Ionization of Unsaturated Hydrocarbons Interacting with High-Power Femtosecond Laser Pulses

Sharifi, Soheil; Talebpour, A.; Chin, See Leang

doi:10.1155/2009/573020

Cited by 4 publications

(6 citation statements)

References 24 publications

(29 reference statements)

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“…Nonsequential double ionization of hydrocarbon molecules in a laser field was previously investigated by mass spectroscopy, and it was found to be the dominating process when the laser intensity is below a few 10 14 W=cm 2 [18][19][20]. The Keldysh parameter [36] indicates that the double ionization step takes place dominantly via tunneling when the laser peak intensity approaches 5 × 10 14 W=cm 2 .…”

Section: Resultsmentioning

confidence: 99%

“…To this end, the experiments employ pulses with durations ranging from the few-cycle regime to 25 fs and intensities from 5 × 10 14 to 2 × 10 15 W=cm 2 . In this intensity range, double ionization is dominated by a sequential dynamics, where two electrons are removed one after another [18][19][20]. Coincidence detection of the resulting fragment ions by ion momentum imaging allows the reconstruction of the fragmentation pathways along different dissociative excited ionic states.…”

Section: Introductionmentioning

confidence: 99%

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Electronic Predetermination of Ethylene Fragmentation Dynamics

et al. 2014

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We experimentally investigate the dependence of the fragmentation behavior of the ethylene dication on the intensity and duration of the laser pulses that initiate the fragmentation dynamics by strong-field double ionization. Using coincidence momentum imaging for the detection of ionic fragments, we disentangle the different contributions of ionization from lower-valence orbitals and field-driven excitation dynamics to the population of certain dissociative excited ionic states that are connected to one of several possible fragmentation pathways towards a given set of fragment ions. We find that the excitation probability to a particular excited state and therewith the outcome of the fragmentation reaction strongly depend on the parameters of the laser pulse. This, in turn, opens up new possibilities for controlling the outcome of fragmentation reactions of polyatomic molecules in that it may allow one to selectively enhance or suppress individual fragmentation channels, which was not possible in previous attempts of controlling fragmentation processes of polyatomic molecules with strong laser fields.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electronic Predetermination of Ethylene Fragmentation Dynamics

et al. 2014

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“…Metastable dications of unsaturated hydrocarbons with lifetimes on the order of nanoseconds have been observed in several TOF studies. 74,75 According to GAUSSIAN 09 calculations for vinyl bromide, removing two electrons from the HOMO orbital requires the lowest total ionization energy for the generation of the dication (27.2 eV). Under the assumption that the lowest energy state of C 2 H 3 Br ++ dications is generated, we perform DFT calculations to estimate the stability of this ion.…”

Section: B Generation and Stability Of C 2 H 3 Br ++ Ionsmentioning

confidence: 99%

Ionization and dissociation dynamics of vinyl bromide probed by femtosecond extreme ultraviolet transient absorption spectroscopy

Lin

Neumark

Geßner

et al. 2014

The Journal of Chemical Physics

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Strong-field induced ionization and dissociation dynamics of vinyl bromide, CH2=CHBr, are probed using femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy. Strong-field ionization is initiated with an intense femtosecond, near infrared (NIR, 775 nm) laser field. Femtosecond XUV pulses covering the photon energy range of 50-72 eV probe the subsequent dynamics by measuring the time-dependent spectroscopic features associated with transitions of the Br (3d) inner-shell electrons to vacancies in molecular and atomic valence orbitals. Spectral signatures are observed for the depletion of neutral C2H3Br, the formation of C2H3Br(+) ions in their ground (X̃) and first excited (Ã) states, the production of C2H3Br(++) ions, and the appearance of neutral Br ((2)P3/2) atoms by dissociative ionization. The formation of free Br ((2)P3/2) atoms occurs on a timescale of 330 ± 150 fs. The ionic Ã state exhibits a time-dependent XUV absorption energy shift of ∼0.4 eV within the time window of the atomic Br formation. The yield of Br atoms correlates with the yield of parent ions in the Ã state as a function of NIR peak intensity. The observations suggest that a fraction of vibrationally excited C2H3Br(+) (Ã) ions undergoes intramolecular vibrational energy redistribution followed by the C-Br bond dissociation. The C2H3Br(+) (X̃) products and the majority of the C2H3Br(++) ions are relatively stable due to a deeper potential well and a high dissociation barrier, respectively. The results offer powerful new insights about orbital-specific electronic processes in high field ionization, coupled vibrational relaxation and dissociation dynamics, and the correlation of valence hole-state location and dissociation in polyatomic molecules, all probed simultaneously by ultrafast table-top XUV spectroscopy.

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“…that C 2 H 6 2+ exhibits the tale tell enhancement 'knee' of Y(A ++ )/ Y(A + ) under linear and circularly polarized pulses 9 . The observation of high-order ATI of ethane; and supported by the observation of NSDI from a number of saturated and unsaturated hydrocarbons 9,11,12 . The sigma bonding electron is responsible for the initial tunnel ionization, leaving a weakly bound M + , evidenced by its lower probability compared to C 2 H 5 + and C 2 H 4 + , this results in a more pronounced yield of dications resulting from NSDI 6,8 .…”

Section: Resultsmentioning

confidence: 65%

“…Processes analogous to those occurring in atoms take place in molecules, albeit with added complexity introduced by the presence of other atoms, molecular structure, additional degrees of freedom, and higher density of electronic states. Furthermore, unlike atoms, molecules, especially nonlinear polyatomic molecules, can experience electron recollision processes at any of their atoms, making possible the observation of NSDI with elliptical and even circularly polarized fields [6][7][8][9][10][11][12][13][14] .…”

mentioning

confidence: 99%

Control of electron recollision and molecular nonsequential double ionization

Sierra-Costa

Michie

et al. 2020

Commun Phys

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Intense laser pulses lasting a few optical cycles, are able to ionize molecules via different mechanisms. One such mechanism involves a process whereby within one optical period an electron tunnels away from the molecule, and is then accelerated and driven back as the laser field reverses its direction, colliding with the parent molecule and causing correlated non-sequential double ionization (NSDI). Here we report control over NSDI via spectral-phase pulse shaping of femtosecond laser pulses. The measurements are carried out on ethane molecules using shaped pulses. We find that the shaped pulses can enhance or suppress the yield of dications resulting from electron recollision by factors of 3 to 6. This type of shaped pulses is likely to impact all phenomena stemming from electron recollision processes induced by strong laser fields such as above threshold ionization, high harmonic generation, attosecond pulse generation, and laser-induced electron diffraction.

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Double Ionization of Unsaturated Hydrocarbons Interacting with High-Power Femtosecond Laser Pulses

Cited by 4 publications

References 24 publications

Electronic Predetermination of Ethylene Fragmentation Dynamics

Electronic Predetermination of Ethylene Fragmentation Dynamics

Ionization and dissociation dynamics of vinyl bromide probed by femtosecond extreme ultraviolet transient absorption spectroscopy

Control of electron recollision and molecular nonsequential double ionization

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