Intensity dependence of the multielectron dissociative ionization of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">N</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>at 305 and 610 nm

Cornaggia, C.; Lavancier, J.; Normand, D.; Morellec, J.; Liu, Huanxiang

doi:10.1103/physreva.42.5464

Cited by 92 publications

(55 citation statements)

References 25 publications

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“…Compared to atoms in intense fields, molecules exhibit complex phenomena arising from their additional (vibrational and rotational) degrees of freedom, such as charge-symmetric and -asymmetric dissociation, [7][8][9] alignment with an external field, 10 creation of electronically excited fragments, 11,12 and ionization rates that depend on the internuclear distance. 9,13,14 In intense laser fields (I > 10 13 W cm À2 ), the Coulombic potentials in which the electrons are placed are greatly distorted: [15][16][17][18] A large part of the electron density is transferred among nuclei within a half optical cycle (%1:3 fs for ! ¼ 800 nm light).…”

Section: Introductionmentioning

confidence: 99%

Theoretical Investigations of the Electronic and Nuclear Dynamics of Molecules in Intense Laser Fields: Quantum Mechanical Wave Packet Approaches

Kono

Satô

Kanno

et al. 2006

Bulletin of the Chemical Society of Japan

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We have developed a method for describing the reaction dynamics of a polyatomic molecule in intense laser fields. First, the dynamical behavior of H 2 þ and H 2 in near-infrared, intense laser fields (I > 10 13 W cm À2 and ! > 700 nm) was examined; accurate evaluation of the electronic and nuclear wave packet was achieved by the dual transformation method that we developed. Using ''field-following'' time-dependent adiabatic states defined as eigenfunctions of the ''instantaneous'' electronic Hamiltonian, we have clarified the dynamics of bound electrons, ionization processes, Coulomb explosion processes, and molecular vibrations of H 2 þ and H 2 . The analyses indicate that the multielectron dynamics and nuclear dynamics of polyatomic molecules in intense fields can be described by using the potential surfaces of time-dependent adiabatic states and the nonadiabatic coupling elements between those states. To obtain time-dependent adiabatic states of a molecule, one can diagonalize the electronic Hamiltonian including the interaction with the instantaneous laser electric field by ab initio molecular orbital (MO) methods. The time-dependent adiabatic potentials obtained are used to evaluate the multichannel nuclear dynamics until the next ionization process. We have applied the time-dependent adiabatic state approach to reveal the characteristic features of the dynamics of structural deformations of CO 2 and its cations in a near-infrared intense laser field. The experimentally observed stretched and bent structure of CO 2 3þ just before Coulomb explosions originates from the structural deformation of CO 2 2þ . We also revealed the mechanism of the experimentally observed bond dissociation of C 2 H 5 OH; we found that the relative probability of C-O bond cleavage to that of C-C bond cleavage becomes smaller with decreases in the pulse length. This example clearly shows that field-induced nonadiabatic transitions play a decisive role in the reaction dynamics of molecules in an intense laser field.

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Section: Introductionmentioning

confidence: 99%

Theoretical Investigations of the Electronic and Nuclear Dynamics of Molecules in Intense Laser Fields: Quantum Mechanical Wave Packet Approaches

Kono

Satô

Kanno

et al. 2006

Bulletin of the Chemical Society of Japan

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“…The work of Tzallas et al [17] provides further evidence that ring opening, induced by strong laser fields, is possible. It therefore seems reasonable to assume that the abovementioned channels are plausible candidates based on the split structure observed in the 70 and 80 m/z range, and the indication in the momentum scaled mass spectrum of NB that the high mass fragments have release momenta consistent with H A number of polarization dependent studies of molecular ionization in the tunnel regime indicate that the ion peak shape is dependent on the amount of geometric or dynamic alignment experienced by the molecule [9,10,12,[45][46][47][48][49][50][51][52]. They generally find suppression of ionization when the polarization is circular, and enhancements of ionization in cases where the polarization is linear, with the CE component emphasized when the laser polarization is collinear with the time-of-flight spectrometer axis.…”

mentioning

confidence: 99%

Femtosecond laser photoionization time-of-flight mass spectrometry of nitro-aromatic explosives and explosives related compounds

Mullen

Coggiola

Oser

2009

J. Am. Soc. Mass Spectrom.

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The ultrafast laser-induced photoionization and photodissociation processes of the nitroaromatic containing explosive and explosive related compounds (ERCs) nitrobenzene (NB), 1,3-dinitrobenzene (DNB), m-nitrotoluene (MNT), 2,4-dinitrotoluene (DNT), and 2,4,6-trinitrotoluene (TNT) have been investigated at three laser wavelengths and power densities using a time-of-flight mass spectrometer. Examination of the mass spectra of these compounds reveals the enhanced formation of the molecular ion [M ϩ ] when ultraviolet (332 nm) and visible (495 nm) light is used relative to infrared (795 nm) radiation. In addition, at 795 nm and a power density of 3.5 ϫ 10 14 W/cm 2 , the presence of a competition between multiphoton ionization (MPI) and Coulomb explosion (CE) channels is revealed by peak shape analysis, and is thought to be operative under these conditions for all of the molecules investigated. [5][6][7][8][9][10][11][12], and polyatomic aromatic organic molecules [13][14][15][16][17][18][19][20][21][22][23], has been the subject of intense investigation. These studies have focused on the fundamental interaction of the laser pulse with the atomic or molecular system, and have generally found a number of operative ionization and dissociation mechanisms present, which are sensitive to the laser wavelength and power density. In addition, a number of studies have also been dedicated to the investigation of the analytical usefulness of femtosecond laser ionization toward molecular specific detection. A prime example is the application to the ionization and detection of the explosives and explosives related compounds pioneered by . Their studies focused on an understanding of the mass spectra obtained using ultrafast laser pulses in conjunction with time-of-flight mass spectrometry, M ϩ ion formation, and specific molecular fragments that could be assigned to a particular precursor species. Of particular interest was the demonstration of isomer dependent mass spectra for the three isomers of nitrotoluene.The motivation to apply femtosecond laser ionization to the study of explosives and ERCs originated from previous laser ionization work, which found that nanosecond laser ionization in the ultraviolet led to extensive molecular fragmentation [31][32][33][34][35][36]. The extensive fragmentation was determined to be non-useful for species-specific identification, even though abundant NO ϩ ions were observed in the mass spectra [37]. The presence of NO ϩ in the mass spectra of these species naturally raised questions regarding its formation. Mechanistically, it was discovered that the dissociative lifetimes of the intermediate states involved in the ionization process were about a few hundred femtoseconds, and that this rapid dissociation led to the extensive fragmentation observed in the mass spectra. Further, the presence of NO ϩ in the mass spectra of these species was attributed to rapid dissociation of the parent molecule (RNO 2 ) producing the NO 2 fragment. The NO 2 molecule undergoes an additional photon absorptio...

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“…Since the applied intensities in these investigations were a factor of about 10 higher than ours the ion temperature in our experiment may still be below 1 eV. However, for molecules the situation is more complicated since additional ion heating may result from a "Coulomb explosion" [28,29]. More investigations of optical-field ionization, especially in molecules, are needed in order to clarify the role of the various physical mechanisms affecting the ion temperature.…”

Section: B Nitrogenmentioning

confidence: 98%

xuv spectra of optical-field-ionized plasmas

et al. 1995

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High-power Ti:sapphire laser pulses (150 mJ in 150 fs) were focused into a gas jet of He, N2, CQ2, 02, SF6, or Ar emitted from a pulsed nozzle. The xuv spectra that were generated are reported and analyzed. For all gases the spectra show strong lines corresponding to single-electron transitions. This indicates that the applied intensities of up to 5 X 10' %/cm' readily strip the atoms of all outer electrons, with three-body recombination populating excited levels of the next lower ionization stage. Simulations of the plasma evolution after the laser pulse were performed for helium and nitrogen. In the case of helium, good agreement with the experiment can be obtained for specific initial conditions. For nitrogen, mechanisms other than three-body recombination must be invoked to explain the experimental spectra. Gain measurements were made by comparing longitudinal and transverse spectra.

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Intensity dependence of the multielectron dissociative ionization ofN2at 305 and 610 nm

Cited by 92 publications

References 25 publications

Theoretical Investigations of the Electronic and Nuclear Dynamics of Molecules in Intense Laser Fields: Quantum Mechanical Wave Packet Approaches

Theoretical Investigations of the Electronic and Nuclear Dynamics of Molecules in Intense Laser Fields: Quantum Mechanical Wave Packet Approaches

Femtosecond laser photoionization time-of-flight mass spectrometry of nitro-aromatic explosives and explosives related compounds

xuv spectra of optical-field-ionized plasmas

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