The Experts below are selected from a list of 5706 Experts worldwide ranked by ideXlab platform
Joshua Jortner - One of the best experts on this subject based on the ideXlab platform.
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Energetics at extremes in Coulomb Explosion of large finite systems
Chemical Physics, 2012Co-Authors: Joshua JortnerAbstract:Abstract Novel features of the dynamics and energetics of clusters and nanodroplets driven by ultraintense, femtosecond, near-infrared laser pulses pertain to the establishment of energetic records for Coulomb Explosion. Theoretical–computational studies demonstrated the attainment of table-top production of deuterons in the energy range of 1–10 MeV by extreme Coulomb Explosion of deuterium nanodroplets/microdroplets with the initial size domain 100–1000 nm (number of constituents 5 × 10 8 –10 11 ), which were driven by superintense lasers with peak intensities of 10 17 –10 20 W cm −2 . This ultrahigh energy range establishes an energetic record for chemical dynamics. New aspects of ultraintense laser-nanostructure interactions involve laser intensity attenuation within the nanodroplet/microdroplet, and a proper treatment of the coupled system with the nanostructure size being comparable to the laser wavelength. Attenuation effects determine an upper size limit of 1 μm of the nanodroplet/microdroplet for useful extreme Coulomb Explosion with an energetic upper limit of 10 MeV for deuterons produced by this table-top process.
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Dynamics of fission and Coulomb Explosion of multicharged large finite systems
Molecular Physics, 2006Co-Authors: Yaakov Levy, Joshua JortnerAbstract:This paper reports on studies of the fragmentation dynamics of multicharged (A+)55 Morse clusters, where the variation of the range of the Morse potential parameters induces cluster fission for a long-range potential and Coulomb Explosion for a short-range potential. The multidimensional energy landscapes for these fragmentation processes were explored by constructing reduced coordinates utilizing the principal component analysis (PCA), which was previously applied for the energy landscapes and folding dynamics of biomolecules. The distance-matrix based PCA was applied to study the effects of the potential on the fragmentation dynamics and to explore the structural diversity of the fragmentation processes. The first principal coordinate (which captures 95% of the dynamic information content for each trajectory) constitutes an appropriate reaction coordinate for both fission and Coulomb Explosion and was used to determine the temperature-dependent fragmentation rates. These obey the Arrhenius law, with the...
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nuclear fusion driven by Coulomb Explosion of methane clusters
Journal of Physical Chemistry A, 2002Co-Authors: Joshua JortnerAbstract:Multielectron ionization and Coulomb Explosion of methane clusters (CA4)n, A = H, D, and T, in very intense (I = 1018−1019 W cm-2) laser fields were studied using classical dynamics simulations. The products of Coulomb Explosion involve light A+ ions (p, d, and t nuclei) with energies up to 20 keV, C4+ ions at I = 1018 W cm-2, and C6+ ions (carbon nuclei) with energies up to 110 keV at I = 1019 W cm-2. Important advantages of nuclear fusion driven by Coulomb Explosion of methane (C4+A4+)n and (C6+A4+)n heteronuclear clusters pertain to energetic effects, with the heavy multielectron ions driving the light H+, D+, or T+ ions (d or t nuclei) to considerably higher energies than for homonuclear deuterium clusters of the same size, and to kinematic effects, which result in a sharp high-energy maximum in the light-ion spectrum for the (C4+A4+)n and(C6 A4+)n clusters. We studied the energetics of Coulomb Explosion in conjunction with isotope effects on the product A+ and Ck+ ions energies and established the cl...
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nuclear fusion induced by Coulomb Explosion of heteronuclear clusters
Physical Review Letters, 2001Co-Authors: Joshua JortnerAbstract:We propose a new mechanism for the production of high-energy (E>3 keV) deuterons, suitable to induce dd nuclear fusion, based on multielectron ionization and Coulomb Explosion of heteronuclear deuterium containing molecular clusters, e.g., (D{sub 2}O){sub n} , in intense (10{sup 16}--2 x 10{sup 18} W/cm{sup 2}) laser fields. Cluster size equations for E , in conjunction with molecular dynamics simulations, reveal important advantages of Coulomb Explosion of (D{sub 2}O){sub n} heteronuclear clusters, as compared with (D){sub n} clusters. These involve the considerably increased D{sup +} kinetic energy and a narrow, high-energy distribution of deuterons.
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nuclear fusion induced by Coulomb Explosion of heteronuclear clusters
Physical Review Letters, 2001Co-Authors: Joshua JortnerAbstract:We propose a new mechanism for the production of high-energy ( $Eg3\mathrm{keV}$) deuterons, suitable to induce $\mathrm{dd}$ nuclear fusion, based on multielectron ionization and Coulomb Explosion of heteronuclear deuterium containing molecular clusters, e.g., $({\mathrm{D}}_{2}\mathrm{O}{)}_{n}$, in intense ( ${10}^{16}--2\ifmmode\times\else\texttimes\fi{}{10}^{18}\mathrm{W}/{\mathrm{cm}}^{2}$) laser fields. Cluster size equations for $E$, in conjunction with molecular dynamics simulations, reveal important advantages of Coulomb Explosion of $({\mathrm{D}}_{2}\mathrm{O}{)}_{n}$ heteronuclear clusters, as compared with $(\mathrm{D}{)}_{n}$ clusters. These involve the considerably increased ${\mathrm{D}}^{+}$ kinetic energy and a narrow, high-energy distribution of deuterons.
Henrik Stapelfeldt - One of the best experts on this subject based on the ideXlab platform.
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communication gas phase structural isomer identification by Coulomb Explosion of aligned molecules
Journal of Chemical Physics, 2018Co-Authors: Michael Burt, Kasra Amini, Claire Vallance, Lars Christiansen, Rasmus R Johansen, Yuki Kobayashi, James D Pickering, M Brouard, Henrik StapelfeldtAbstract:The gas-phase structures of four difluoroiodobenzene and two dihydroxybromobenzene isomers were identified by correlating the emission angles of atomic fragment ions created, following femtosecond laser-induced Coulomb Explosion. The structural determinations were facilitated by confining the most polarizable axis of each molecule to the detection plane prior to the Coulomb Explosion event using one-dimensional laser-induced adiabatic alignment. For a molecular target consisting of two difluoroiodobenzene isomers, each constituent structure could additionally be singled out and distinguished.
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Observing molecular dynamics with timed Coulomb Explosion imaging
Philosophical Transactions of the Royal Society of London. Series A: Mathematical Physical and Engineering Sciences, 1998Co-Authors: Ch. Ellert, Henrik Stapelfeldt, Eric Constant, Hirofumi Sakai, James S. Wright, David M. Rayner, Paul B. CorkumAbstract:The Coulomb Explosion method for imaging molecular structure is combined with the femtosecond pump–probe technique. Thus the imaging method becomes flexible enough to determine molecular structure even in highly excited or transient states as a function of time. Examples for the applicability of this method are given. The major concerns which could limit the reliability and the accuracy of the information extracted are discussed and solutions proposed. In addition to observing time–dependent structures, optically triggered Coulomb Explosion imaging can be used to identify unusual events in an ensemble of common but more frequent events.
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Imaging of ions produced by femtosecond laser induced Coulomb Explosion of molecules
Springer Series in Chemical Physics, 1998Co-Authors: Jakob Juul Larsen, N. Bjerre, Nils Jakob Mørkbak, Johannes Olesen, Søren Rud Keiding, Henrik StapelfeldtAbstract:We use two dimensional ion imaging to analyze the fragments from femtosecond laser induced Coulomb Explosion of molecules. The ion imaging technique enables measurements of the energy and angular distribution of highly charged ions produced in the Coulomb Explosion process. Also, the dynamics of photodissociation of I2 is studied by recording 2-D images as a function of the delay between a pump pulse, initiating the dissociation, and an intense probe pulse, Coulomb exploding the dissociating molecules.
Michael Burt - One of the best experts on this subject based on the ideXlab platform.
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Coulomb Explosion imaging of CH3I and CH2ClI photodissociation dynamics.
The Journal of chemical physics, 2018Co-Authors: Felix Allum, Cédric Bomme, Michael Burt, Kasra Amini, Rebecca Boll, Hansjochen Köckert, Pavel K. Olshin, Sadia Bari, Felix Brauße, Barbara Cunha De MirandaAbstract:The photodissociation dynamics of CH3I and CH2ClI at 272 nm were investigated by time-resolved Coulomb Explosion imaging, with an intense non-resonant 815 nm probe pulse. Fragment ion momenta over a wide m/z range were recorded simultaneously by coupling a velocity map imaging spectrometer with a pixel imaging mass spectrometry camera. For both molecules, delay-dependent pump-probe features were assigned to ultraviolet-induced carbon-iodine bond cleavage followed by Coulomb Explosion. Multi-mass imaging also allowed the sequential cleavage of both carbon-halogen bonds in CH2ClI to be investigated. Furthermore, delay-dependent relative fragment momenta of a pair of ions were directly determined using recoil-frame covariance analysis. These results are complementary to conventional velocity map imaging experiments and demonstrate the application of time-resolved Coulomb Explosion imaging to photoinduced real-time molecular motion.
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Coulomb Explosion imaging of ch 3 i and ch 2 cli photodissociation dynamics
Journal of Chemical Physics, 2018Co-Authors: Felix Allum, Cédric Bomme, Michael Burt, Kasra Amini, Rebecca Boll, Hansjochen Köckert, Pavel K. Olshin, Sadia Bari, Felix Brause, Barbara Cunha De MirandaAbstract:The photodissociation dynamics of CH3I and CH2ClI at 272 nm were investigated by time-resolved Coulomb Explosion imaging, with an intense non-resonant 815 nm probe pulse. Fragment ion momenta over a wide m/z range were recorded simultaneously by coupling a velocity map imaging spectrometer with a pixel imaging mass spectrometry camera. For both molecules, delay-dependent pump-probe features were assigned to ultraviolet-induced carbon-iodine bond cleavage followed by Coulomb Explosion. Multi-mass imaging also allowed the sequential cleavage of both carbon-halogen bonds in CH2ClI to be investigated. Furthermore, delay-dependent relative fragment momenta of a pair of ions were directly determined using recoil-frame covariance analysis. These results are complementary to conventional velocity map imaging experiments and demonstrate the application of time-resolved Coulomb Explosion imaging to photoinduced real-time molecular motion.
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communication gas phase structural isomer identification by Coulomb Explosion of aligned molecules
Journal of Chemical Physics, 2018Co-Authors: Michael Burt, Kasra Amini, Claire Vallance, Lars Christiansen, Rasmus R Johansen, Yuki Kobayashi, James D Pickering, M Brouard, Henrik StapelfeldtAbstract:The gas-phase structures of four difluoroiodobenzene and two dihydroxybromobenzene isomers were identified by correlating the emission angles of atomic fragment ions created, following femtosecond laser-induced Coulomb Explosion. The structural determinations were facilitated by confining the most polarizable axis of each molecule to the detection plane prior to the Coulomb Explosion event using one-dimensional laser-induced adiabatic alignment. For a molecular target consisting of two difluoroiodobenzene isomers, each constituent structure could additionally be singled out and distinguished.
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Coulomb-Explosion imaging of concurrent CH2BrI photodissociation dynamics
Physical Review A, 2017Co-Authors: Michael Burt, Kasra Amini, Rebecca Boll, Hansjochen Köckert, Sadia Bari, Jason W. L. Lee, Claire Vallance, Alexander S. Gentleman, Stuart R. Mackenzie, Cédric BommeAbstract:The dynamics following laser-induced molecular photodissociation of gas-phase CH2BrI at 271.6 nm were investigated by time-resolved Coulomb-Explosion imaging using intense near-IR femtosecond laser pulses. The observed delay-dependent photofragment momenta reveal that CH2BrI undergoes C-I cleavage, depositing 65.6% of the available energy into internal product states, and that absorption of a second UV photon breaks the C-Br bond of CH2Br. Simulations confirm that this mechanism is consistent with previous data recorded at 248 nm, demonstrating the sensitivity of Coulomb-Explosion imaging as a real-time probe of chemical dynamics.
David M. Villeneuve - One of the best experts on this subject based on the ideXlab platform.
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Wavelength-dependent study of strong-field Coulomb Explosion of hydrogen
New Journal of Physics, 2008Co-Authors: Igor Litvinyuk, Ali S. Alnaser, D. Comtois, Dipanwita Ray, A. T. Hasan, J. C. Kieffer, David M. VilleneuveAbstract:We present the first systematic wavelength-dependent study of laser Coulomb Explosion of deuterium molecules at various peak intensities and polarizations. We measured the kinetic energy spectra of D+ for laser wavelengths in the range 480–2000 nm. In addition to the well-known enhanced ionization channel present for all wavelengths, we observe a new high-energy band at short wavelengths. This new band exhibits wavelength dependence, with fragment energy decreasing with increasing wavelengths until it merges with the enhanced ionization band for 800 nm and longer. We attribute the emergence of this band to a new pathway that involves resonant three-photon coupling to the first excited electronic state of the molecular ion during the Coulomb Explosion process. This pathway should be accounted for in controlling molecular dynamics of hydrogen by intense laser pulses.
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Laser Coulomb Explosion imaging for probing ultra-fast molecular dynamics
Journal of Physics B: Atomic Molecular and Optical Physics, 2006Co-Authors: François Légaré, Kevin F. Lee, André D. Bandrauk, David M. Villeneuve, Paul B. CorkumAbstract:We use laser Coulomb Explosion imaging (CEI) to measure structural change during molecular ultra-fast dynamics. We obtain time information with a pump–probe approach using few-cycle laser pulses (
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Laser Coulomb-Explosion imaging of small molecules
Physical Review A, 2005Co-Authors: François Légaré, Kevin F. Lee, Igor Litvinyuk, P. W. Dooley, S. S. Wesolowski, P. R. Bunker, Péter Dombi, Ferenc Krausz, André D. Bandrauk, David M. VilleneuveAbstract:We use intense few-cycle laser pulses to ionize molecules to the point of Coulomb Explosion. We use Coulomb's law or ab initio potentials to reconstruct the molecular structure of D{sub 2}O and SO{sub 2} from the correlated momenta of exploded fragments. For D{sub 2}O, a light and fast system, we observed about 0.3 A and 15 deg. deviation from the known bond length and bond angle. By simulating the Coulomb Explosion for equilibrium geometry, we showed that this deviation is mainly caused by ion motion during ionization. Measuring three-dimensional structure with half bond length resolution is sufficient to observe large-scale rearrangements of small molecules such as isomerization processes.
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Laser Coulomb Explosion imaging for probing molecular structure and dynamics
Springer Series in Chemical Physics, 2005Co-Authors: François Légaré, Kevin F. Lee, Igor Litvinyuk, P. W. Dooley, André D. Bandrauk, David M. Villeneuve, Paul B. CorkumAbstract:We measure molecular structure of D2O and SO2 with ~0.3-Angstrom resolution using laser Coulomb Explosion imaging. Exciting a vibrational wave packet we observe 3-D molecular dynamics with sub-5fs resolution.
Kasra Amini - One of the best experts on this subject based on the ideXlab platform.
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Coulomb Explosion imaging of CH3I and CH2ClI photodissociation dynamics.
The Journal of chemical physics, 2018Co-Authors: Felix Allum, Cédric Bomme, Michael Burt, Kasra Amini, Rebecca Boll, Hansjochen Köckert, Pavel K. Olshin, Sadia Bari, Felix Brauße, Barbara Cunha De MirandaAbstract:The photodissociation dynamics of CH3I and CH2ClI at 272 nm were investigated by time-resolved Coulomb Explosion imaging, with an intense non-resonant 815 nm probe pulse. Fragment ion momenta over a wide m/z range were recorded simultaneously by coupling a velocity map imaging spectrometer with a pixel imaging mass spectrometry camera. For both molecules, delay-dependent pump-probe features were assigned to ultraviolet-induced carbon-iodine bond cleavage followed by Coulomb Explosion. Multi-mass imaging also allowed the sequential cleavage of both carbon-halogen bonds in CH2ClI to be investigated. Furthermore, delay-dependent relative fragment momenta of a pair of ions were directly determined using recoil-frame covariance analysis. These results are complementary to conventional velocity map imaging experiments and demonstrate the application of time-resolved Coulomb Explosion imaging to photoinduced real-time molecular motion.
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Coulomb Explosion imaging of ch 3 i and ch 2 cli photodissociation dynamics
Journal of Chemical Physics, 2018Co-Authors: Felix Allum, Cédric Bomme, Michael Burt, Kasra Amini, Rebecca Boll, Hansjochen Köckert, Pavel K. Olshin, Sadia Bari, Felix Brause, Barbara Cunha De MirandaAbstract:The photodissociation dynamics of CH3I and CH2ClI at 272 nm were investigated by time-resolved Coulomb Explosion imaging, with an intense non-resonant 815 nm probe pulse. Fragment ion momenta over a wide m/z range were recorded simultaneously by coupling a velocity map imaging spectrometer with a pixel imaging mass spectrometry camera. For both molecules, delay-dependent pump-probe features were assigned to ultraviolet-induced carbon-iodine bond cleavage followed by Coulomb Explosion. Multi-mass imaging also allowed the sequential cleavage of both carbon-halogen bonds in CH2ClI to be investigated. Furthermore, delay-dependent relative fragment momenta of a pair of ions were directly determined using recoil-frame covariance analysis. These results are complementary to conventional velocity map imaging experiments and demonstrate the application of time-resolved Coulomb Explosion imaging to photoinduced real-time molecular motion.
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communication gas phase structural isomer identification by Coulomb Explosion of aligned molecules
Journal of Chemical Physics, 2018Co-Authors: Michael Burt, Kasra Amini, Claire Vallance, Lars Christiansen, Rasmus R Johansen, Yuki Kobayashi, James D Pickering, M Brouard, Henrik StapelfeldtAbstract:The gas-phase structures of four difluoroiodobenzene and two dihydroxybromobenzene isomers were identified by correlating the emission angles of atomic fragment ions created, following femtosecond laser-induced Coulomb Explosion. The structural determinations were facilitated by confining the most polarizable axis of each molecule to the detection plane prior to the Coulomb Explosion event using one-dimensional laser-induced adiabatic alignment. For a molecular target consisting of two difluoroiodobenzene isomers, each constituent structure could additionally be singled out and distinguished.
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Coulomb-Explosion imaging of concurrent CH2BrI photodissociation dynamics
Physical Review A, 2017Co-Authors: Michael Burt, Kasra Amini, Rebecca Boll, Hansjochen Köckert, Sadia Bari, Jason W. L. Lee, Claire Vallance, Alexander S. Gentleman, Stuart R. Mackenzie, Cédric BommeAbstract:The dynamics following laser-induced molecular photodissociation of gas-phase CH2BrI at 271.6 nm were investigated by time-resolved Coulomb-Explosion imaging using intense near-IR femtosecond laser pulses. The observed delay-dependent photofragment momenta reveal that CH2BrI undergoes C-I cleavage, depositing 65.6% of the available energy into internal product states, and that absorption of a second UV photon breaks the C-Br bond of CH2Br. Simulations confirm that this mechanism is consistent with previous data recorded at 248 nm, demonstrating the sensitivity of Coulomb-Explosion imaging as a real-time probe of chemical dynamics.
