Coulomb explosion of benzene irradiated by an intense femtosecond laser pulse

Shimizu, Seiji; Kou, Junkei; Kawato, Sakae; Shimizu, Keisuke; Shimizu, Shuji; Nakashima, Nobuaki

doi:10.1016/s0009-2614(99)01376-7

Cited by 69 publications

(35 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…20,[30][31][32]39 As in the case of H 2 þ , both the original electronic wave function È and the HamiltonianĤ H are transformed to È T andĤ H T consistently so that the numerical difficulties arising from the divergence of the Coulomb potentials are overcome. The time integration of the Schrödinger equation…”

Section: Two-electron Dynamics Of H 2 In An Intense Laser Fieldmentioning

confidence: 99%

“…9,13,14,[27][28][29][30] Enhanced ionization has been experimentally observed for various molecules, 27-30 such as CO 2 23 and benzene molecules. 31 The correlation between ionization and structural deformation plays a key role in fragmentation or reaction processes. [32][33][34] In other words, the competition between ionization and fragmentation governs the fate of the molecule in an intense field.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

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.

show abstract

Section: Two-electron Dynamics Of H 2 In An Intense Laser Fieldmentioning

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…Once the laser strips electrons from the molecule, the remaining positively charged structure can explode, creating a molecular plasma cloud. Coulomb explosion can be used to generate bright keV x-ray photons [14,15], highly energetic electrons [16], and for imaging [17][18][19].The strong-field ionization and fragmentation of hydrocarbon molecules is a prototypical example of the Coulomb explosion of polyatomic molecules, and it has been the subject of several experiments [9,11,[20][21][22][23]]. An important quantity measured in these experiments is the kinetic energy distribution of the protons ejected during the fragmentation.…”

mentioning

confidence: 99%

“…The strong-field ionization and fragmentation of hydrocarbon molecules is a prototypical example of the Coulomb explosion of polyatomic molecules, and it has been the subject of several experiments [9,11,[20][21][22][23]]. An important quantity measured in these experiments is the kinetic energy distribution of the protons ejected during the fragmentation.…”

mentioning

confidence: 99%

Strong laser-pulse-driven ionization and Coulomb explosion of hydrocarbon molecules

et al. 2012

View full text Add to dashboard Cite

Field ionization and Coulomb explosion of small hydrocarbon molecules driven by intense laser pulses are studied in a combined theoretical and experimental framework. The spectra of ejected protons calculated by the time-dependent density functional approach are in good agreement with the experimental data. The results of the simulations give detailed insight into the correlated electron and nuclear dynamics and complement the experiment with a time-dependent physical picture. It is demonstrated that the Coulomb explosion in the studied molecular systems is a sudden, all-at-once fragmentation where the ionization step is followed by a simultaneous ejection of the charged fragments. [7], and Coulomb explosion [8,9]. Highly energetic dissociation of a molecule or solid due to multiple ionization, known as the Coulomb explosion, is a particularly interesting process because it exposes the key physical mechanisms associated with the electron and nuclear dynamics and ionization [9][10][11][12][13]. Once the laser strips electrons from the molecule, the remaining positively charged structure can explode, creating a molecular plasma cloud. Coulomb explosion can be used to generate bright keV x-ray photons [14,15], highly energetic electrons [16], and for imaging [17][18][19].The strong-field ionization and fragmentation of hydrocarbon molecules is a prototypical example of the Coulomb explosion of polyatomic molecules, and it has been the subject of several experiments [9,11,[20][21][22][23]]. An important quantity measured in these experiments is the kinetic energy distribution of the protons ejected during the fragmentation. Proton energies in excess of 30 eV at only very moderate peak intensities of the driving laser pulses have been reported for both large [11] and small hydrocarbon molecules [9]. The proton kinetic cutoff energies depend sensitively on the laser intensity and saturate at intensities that depend on the molecular species [9,11]. Earlier, this behavior was attributed to the creation of a long-lived charge localization state [11]. A more recent experiment [9], in contrast, suggested that the high kinetic proton energies originate from Coulomb explosions from a high molecular charge state. It was suggested [9] that a multibond version of the enhanced ionization process [24,25] is responsible for reaching the observed high charge states, from which the protons are ejected simultaneously in a concerted Coulomb explosion process resulting in complete molecular fragmentations. A recent theoretical study [26] using a one-dimensional model of acetylene, C 2 H 2 , confirms the proposed ionization mechanism leading to the high charge states, but it did not investigate the fragmentation dynamics. While the experimental approaches allow the study of important aspects of the Coulomb explosion of molecules by analyzing the properties of the resulting fragments, they do not provide a complete, dynamical description of the internal mechanism taking place during the fragmentation.In this work, the intense laser puls...

show abstract

“…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.…”

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.

View full text Add to dashboard Cite

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...

show abstract

Coulomb explosion of benzene irradiated by an intense femtosecond laser pulse

Cited by 69 publications

References 17 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

Strong laser-pulse-driven ionization and Coulomb explosion of hydrocarbon molecules

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

Contact Info

Product

Resources

About