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Lars Bojer Madsen - One of the best experts on this subject based on the ideXlab platform.
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Inter- and intracycle interference effects in strong-field Dissociative Ionization
Physical Review A, 2016Co-Authors: Lun Yue, Lars Bojer MadsenAbstract:The energy sharing between the electron and nuclei is studied in detail for strong-field Dissociative Ionization of H${}_{2}^{+}$ molecular ions, where the fine-grained structures that appear to violate a simple energy conservation rule are now understood by inter- and intracycle interferences.
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Interference Effects in Strong-Field Dissociative Ionization
arXiv: Atomic Physics, 2015Co-Authors: Lun Yue, Lars Bojer MadsenAbstract:We theoretically study Dissociative Ionization of H$_2^+$ exposed to strong linearly polarized few-cycle visible, near-infrared and midinfrared laser pulses. We find rich energy-sharing structures in the combined electron and nuclear kinetic energy spectra with features that are a priori at odds with simple energy conservation arguments. We explain the structures as interferences between wave packets released during different optical cycles, and during the same optical cycle, respectively. Both inter- and intracycle interference structures are clearly visible in the joint energy spectra. The shapes of the interference structures depend on the dynamics leading to the double continuum, and carry sub-femtosecond information.
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Dissociation and Dissociative Ionization of H2 + using the time-dependent surface flux method
Physical Review A, 2013Co-Authors: Lun Yue, Lars Bojer MadsenAbstract:The time-dependent surface flux method developed for the description of electronic spectra [L. Tao and A. Scrinzi, New J. Phys. 14, 013021 (2012); A. Scrinzi, New J. Phys. 14, 085008 (2012)] is extended to treat dissociation and Dissociative Ionization processes of H2+ interacting with strong laser pulses. By dividing the simulation volume into proper spatial regions associated with the individual reaction channels and monitoring the probability flux, the joint energy spectrum for the Dissociative Ionization process and the energy spectrum for dissociation is obtained. The methodology is illustrated by solving the time-dependent Schr\"{o}dinger equation (TDSE) for a collinear one-dimensional model of H2+ with electronic and nuclear motions treated exactly and validated by comparison with published results for Dissociative Ionization. The results for dissociation are qualitatively explained by analysis based on dressed diabatic Floquet potential energy curves, and the method is used to investigate the breakdown of the two-surface model.
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dissociation and Dissociative Ionization of h2 using the time dependent surface flux method
Physical Review A, 2013Co-Authors: Lun Yue, Lars Bojer MadsenAbstract:The time-dependent surface flux method developed for the description of electronic spectra [L. Tao and A. Scrinzi, New J. Phys. 14, 013021 (2012); A. Scrinzi, New J. Phys. 14, 085008 (2012)] is extended to treat dissociation and Dissociative Ionization processes of H2+ interacting with strong laser pulses. By dividing the simulation volume into proper spatial regions associated with the individual reaction channels and monitoring the probability flux, the joint energy spectrum for the Dissociative Ionization process and the energy spectrum for dissociation is obtained. The methodology is illustrated by solving the time-dependent Schr\"{o}dinger equation (TDSE) for a collinear one-dimensional model of H2+ with electronic and nuclear motions treated exactly and validated by comparison with published results for Dissociative Ionization. The results for dissociation are qualitatively explained by analysis based on dressed diabatic Floquet potential energy curves, and the method is used to investigate the breakdown of the two-surface model.
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electron nuclear energy sharing in above threshold multiphoton Dissociative Ionization of h2
Physical Review Letters, 2013Co-Authors: Maksim Kunitski, Lars Bojer Madsen, M Pitzer, F Trinter, Ph L H Schmidt, T Jahnke, Maia Magrakvelidze, C B Madsen, Uwe Thumm, R. DörnerAbstract:We report experimental observation of the energy sharing between electron and nuclei in abovethreshold multiphoton Dissociative Ionization of H2 by strong laser fields. The absorbed photon energy is shared between the ejected electron and nuclei in a correlated fashion, resulting in multiple diagonal lines in their joint energy spectrum governed by the energy conservation of all fragment particles. Deposition of the photon energy to atoms and molecules is the primary step of the interactions of radiation with matter. The details of this deposition process, in particular how the photon energy is distributed among the subsystems and various internal degrees of freedom, determine all photon-induced chemical and physical dynamics. For the interaction with a strong laser field, this question of energy deposition gets even richer since it is well established that the energy of more photons than the minimal number required for Ionization can be absorbed. For atoms in a strong field, this leads to discrete peaks in the photoelectron spectrum that are spaced by the photon energy and referred to as ‘‘above-threshold Ionization’’ (ATI) [1]. For molecules the vibrational, rotational, and Dissociative motions of the nuclei provide a sink for the photon energy in addition to the electrons. This has been observed in single-photon Dissociative Ionization of molecules exposed to synchrotron radiation [2–4], where the photon energy is shared by the freed electrons and the nuclear fragments. For the molecular multiphoton case, rich ATI spectra of the freed electron [5–9], bond-softening-induced molecular Dissociative Ionization [10–15], and the imaging of internuclear distance using nuclear kinetic energy release spectra [16–19] have been reported. The correlation between the fragment ion and the electron energy has most recently been studied in numerical simulations for H 2 þ [20,21]. A nontrivial sharingof the absorbedphoton energy between the electron and nuclei in multiphoton Ionization of molecules was predicted and stimulated us to investigate this problem experimentally. Here, we report the experimental observation of the energy sharing between the emitted electron and nuclei from above-threshold multiphoton Dissociative Ionization of the simplest molecule H 2 by intense femtosecond laser pulses. Discrete numbers of absorbed photons can be identified by peaked diagonal lines in the joint energy spectrum (JES) of the coincidently measured electron and nuclei [20]. Since there is no direct coupling between the nuclei and the laser field for homonuclear diatomic molecules, the laser first couples to the electrons, and the electrons then couple to the nuclei. The energy taken by the nuclei therefore measures the correlation between the electrons and nuclei. Figure 1 shows a much simplified schematics of the process. By absorbing multiple photons (blue vertical arrows), the H2 molecule emits one electron and a nuclear wavepacket on the � þ (ground) state of H 2 þ is launched. It propagates on the � þ potential curve of H 2 þ .P art of this wavepacket already has sufficient energy to escape (direct pathway), while another part can be promoted to the Dissociative � þ potential curve by resonant absorption of one additional photon (one-photon pathway). In the multiphoton picture, the sum of the kinetic energy of the proton (Ep), hydrogen atom (EH), and electron (Ee) after the end of the laser pulse is given by
Yunquan Liu - One of the best experts on this subject based on the ideXlab platform.
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laser wavelength and intensity dependence of electron nuclear energy sharing in Dissociative Ionization of h 2
Physical Review A, 2020Co-Authors: Hao Liang, Yunquan Liu, Mingming Liu, Liangyou PengAbstract:We experimentally and theoretically study the photoelectron-nuclear energy sharing mechanism of the correlated dynamics between the photoelectrons and the fragmented ions in the Dissociative Ionization of ${\mathrm{H}}_{2}$ with respect to the laser intensity at the wavelengths $\ensuremath{\lambda}=395\phantom{\rule{0.16em}{0ex}}\mathrm{nm}$ and $\ensuremath{\lambda}=790\phantom{\rule{0.16em}{0ex}}\mathrm{nm}$. We show that the prominent photoelectron-nuclear energy sharing along the back-diagonal lines is only observed for 395 nm at lower intensities, which is absent for increased intensities at 395 nm and for 790 nm lasers over a wide range of intensities. Based on a quantum mechanical model that includes the correlation between the photoelectron and the parent ion, we show that bond hardening has a significant effect on the photoelectron-nuclear energy sharing. The resonant states of the neutral hydrogen molecule during strong-field Ionization and the distribution of vibrational states of molecular ions determine the joint energy spectrum of photoelectrons and nuclei. The study provides an intuitive and comprehensive description and understanding of the correlated photoelectron-nuclear dynamics in the Dissociative Ionization.
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Dissociative Ionization of Argon Dimer by Intense Femtosecond Laser Pulses
The Journal of Physical Chemistry A, 2017Co-Authors: Qian Cheng, Xiguo Xie, Zongqiang Yuan, Xunqi Zhong, Yunquan Liu, Qihuang GongAbstract:We experimentally and theoretically studied Dissociative Ionization of argon dimer driven by intense femtosecond laser pulses. In the experiment, we measured the ion yield and the angular distribution of fragmental ions generated from the Dissociative Ionization channels of (1,1) (Ar22+ → Ar+ + Ar+) and (2,1) (Ar23+ → Ar2+ + Ar+) using a cold target recoil ion momentum spectroscopy. The channel ratio of (2,1)/(1,1) is 4.5–7.5 times of the yield ratio of double Ionization to single Ionization of argon monomer depending on the laser intensity. The measurement verified that the Ionization of Ar+ is greatly enhanced if there exists a neighboring Ar+ separated by a critical distance. In addition, the fragmental ions exhibit an anisotropic angular distribution with the peak along the laser polarization direction and the full width at half maximum becomes broader with increasing laser intensity. Using a full three-dimensional classical ensemble model, we calculated the angle-dependent multiple Ionization probabi...
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Steering of Molecular Multiple Dissociative Ionization with Strong Few-Cycle Laser Fields
Springer Proceedings in Physics, 2012Co-Authors: Yunquan Liu, Xianrong Liu, Yongkai Deng, Qihuang GongAbstract:Coherent control is an implicit goal of quantum physics and quantum chemistry, which have been significantly developed in utilizing light to control over the dynamics of atomic and molecular systems. We show that the process of multiple Dissociative Ionization of carbon monoxide (CO) molecules is controllable using an intense phase-stabilized few-cycle laser field (4.2 fs, 740 nm, \(6 \times 1{0}^{14}\,\mathrm{W}/{\mathrm{cm}}^{2})\). We demonstrate that the controllable emission direction of \({\mathrm{C}}^{2+}\) from charge asymmetrical dissociation and Ionization of CO dications is out of phase in a linearly polarized laser field. The strong coupling between the Dissociative channels is explained with the mechanisms of recollision excitation and recollision Ionization. The competition between excitation and Ionization in a recollision process leads to the opposite asymmetrical property. The results provide an insight into the controllable attosecond dynamics of multiple Dissociative Ionization of a complex molecule.
R. Dörner - One of the best experts on this subject based on the ideXlab platform.
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electron nuclear energy sharing in above threshold multiphoton Dissociative Ionization of h2
Physical Review Letters, 2013Co-Authors: Maksim Kunitski, Lars Bojer Madsen, M Pitzer, F Trinter, Ph L H Schmidt, T Jahnke, Maia Magrakvelidze, C B Madsen, Uwe Thumm, R. DörnerAbstract:We report experimental observation of the energy sharing between electron and nuclei in abovethreshold multiphoton Dissociative Ionization of H2 by strong laser fields. The absorbed photon energy is shared between the ejected electron and nuclei in a correlated fashion, resulting in multiple diagonal lines in their joint energy spectrum governed by the energy conservation of all fragment particles. Deposition of the photon energy to atoms and molecules is the primary step of the interactions of radiation with matter. The details of this deposition process, in particular how the photon energy is distributed among the subsystems and various internal degrees of freedom, determine all photon-induced chemical and physical dynamics. For the interaction with a strong laser field, this question of energy deposition gets even richer since it is well established that the energy of more photons than the minimal number required for Ionization can be absorbed. For atoms in a strong field, this leads to discrete peaks in the photoelectron spectrum that are spaced by the photon energy and referred to as ‘‘above-threshold Ionization’’ (ATI) [1]. For molecules the vibrational, rotational, and Dissociative motions of the nuclei provide a sink for the photon energy in addition to the electrons. This has been observed in single-photon Dissociative Ionization of molecules exposed to synchrotron radiation [2–4], where the photon energy is shared by the freed electrons and the nuclear fragments. For the molecular multiphoton case, rich ATI spectra of the freed electron [5–9], bond-softening-induced molecular Dissociative Ionization [10–15], and the imaging of internuclear distance using nuclear kinetic energy release spectra [16–19] have been reported. The correlation between the fragment ion and the electron energy has most recently been studied in numerical simulations for H 2 þ [20,21]. A nontrivial sharingof the absorbedphoton energy between the electron and nuclei in multiphoton Ionization of molecules was predicted and stimulated us to investigate this problem experimentally. Here, we report the experimental observation of the energy sharing between the emitted electron and nuclei from above-threshold multiphoton Dissociative Ionization of the simplest molecule H 2 by intense femtosecond laser pulses. Discrete numbers of absorbed photons can be identified by peaked diagonal lines in the joint energy spectrum (JES) of the coincidently measured electron and nuclei [20]. Since there is no direct coupling between the nuclei and the laser field for homonuclear diatomic molecules, the laser first couples to the electrons, and the electrons then couple to the nuclei. The energy taken by the nuclei therefore measures the correlation between the electrons and nuclei. Figure 1 shows a much simplified schematics of the process. By absorbing multiple photons (blue vertical arrows), the H2 molecule emits one electron and a nuclear wavepacket on the � þ (ground) state of H 2 þ is launched. It propagates on the � þ potential curve of H 2 þ .P art of this wavepacket already has sufficient energy to escape (direct pathway), while another part can be promoted to the Dissociative � þ potential curve by resonant absorption of one additional photon (one-photon pathway). In the multiphoton picture, the sum of the kinetic energy of the proton (Ep), hydrogen atom (EH), and electron (Ee) after the end of the laser pulse is given by
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Orientation and impact-parameter dependence of Dissociative Ionization of H2 by slow ion impact
Journal of Physics B: Atomic Molecular and Optical Physics, 2007Co-Authors: F. Afaneh, L. Ph. H. Schmidt, Markus Schöffler, K. E. Stiebing, J. Al-jundi, H. Schmidt-böcking, R. DörnerAbstract:We have used the cold target recoil ion momentum spectroscopy imaging technique to investigate Dissociative Ionization of H2 by 25 keV proton impact. A kinematically complete picture of the Dissociative Ionization dynamics for slow proton collision has been obtained. The results show a strong impactparameter dependence of the fragmentation process of H2. This clearly emerged in the energy distributions of the H + ions generated for different impact parameters. At large impact parameters the H + ions equally share the energy liberated in the collision whereas at small impact parameters, the energy sharing is quite asymmetric. We also observed a strong dependence of the electron emission on molecular alignment. The momentum distribution of the emitted electron generated for a fixed-in-space H2 molecule displays that the electrons are more likely to be emitted perpendicular to the molecular axis.
Lun Yue - One of the best experts on this subject based on the ideXlab platform.
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Inter- and intracycle interference effects in strong-field Dissociative Ionization
Physical Review A, 2016Co-Authors: Lun Yue, Lars Bojer MadsenAbstract:The energy sharing between the electron and nuclei is studied in detail for strong-field Dissociative Ionization of H${}_{2}^{+}$ molecular ions, where the fine-grained structures that appear to violate a simple energy conservation rule are now understood by inter- and intracycle interferences.
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Interference Effects in Strong-Field Dissociative Ionization
arXiv: Atomic Physics, 2015Co-Authors: Lun Yue, Lars Bojer MadsenAbstract:We theoretically study Dissociative Ionization of H$_2^+$ exposed to strong linearly polarized few-cycle visible, near-infrared and midinfrared laser pulses. We find rich energy-sharing structures in the combined electron and nuclear kinetic energy spectra with features that are a priori at odds with simple energy conservation arguments. We explain the structures as interferences between wave packets released during different optical cycles, and during the same optical cycle, respectively. Both inter- and intracycle interference structures are clearly visible in the joint energy spectra. The shapes of the interference structures depend on the dynamics leading to the double continuum, and carry sub-femtosecond information.
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Dissociation and Dissociative Ionization of H2 + using the time-dependent surface flux method
Physical Review A, 2013Co-Authors: Lun Yue, Lars Bojer MadsenAbstract:The time-dependent surface flux method developed for the description of electronic spectra [L. Tao and A. Scrinzi, New J. Phys. 14, 013021 (2012); A. Scrinzi, New J. Phys. 14, 085008 (2012)] is extended to treat dissociation and Dissociative Ionization processes of H2+ interacting with strong laser pulses. By dividing the simulation volume into proper spatial regions associated with the individual reaction channels and monitoring the probability flux, the joint energy spectrum for the Dissociative Ionization process and the energy spectrum for dissociation is obtained. The methodology is illustrated by solving the time-dependent Schr\"{o}dinger equation (TDSE) for a collinear one-dimensional model of H2+ with electronic and nuclear motions treated exactly and validated by comparison with published results for Dissociative Ionization. The results for dissociation are qualitatively explained by analysis based on dressed diabatic Floquet potential energy curves, and the method is used to investigate the breakdown of the two-surface model.
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dissociation and Dissociative Ionization of h2 using the time dependent surface flux method
Physical Review A, 2013Co-Authors: Lun Yue, Lars Bojer MadsenAbstract:The time-dependent surface flux method developed for the description of electronic spectra [L. Tao and A. Scrinzi, New J. Phys. 14, 013021 (2012); A. Scrinzi, New J. Phys. 14, 085008 (2012)] is extended to treat dissociation and Dissociative Ionization processes of H2+ interacting with strong laser pulses. By dividing the simulation volume into proper spatial regions associated with the individual reaction channels and monitoring the probability flux, the joint energy spectrum for the Dissociative Ionization process and the energy spectrum for dissociation is obtained. The methodology is illustrated by solving the time-dependent Schr\"{o}dinger equation (TDSE) for a collinear one-dimensional model of H2+ with electronic and nuclear motions treated exactly and validated by comparison with published results for Dissociative Ionization. The results for dissociation are qualitatively explained by analysis based on dressed diabatic Floquet potential energy curves, and the method is used to investigate the breakdown of the two-surface model.
Maksim Kunitski - One of the best experts on this subject based on the ideXlab platform.
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Multielectron effects in strong-field Dissociative Ionization of molecules
Physical Review A, 2014Co-Authors: Xiaochun Gong, L. Ph. H. Schmidt, K.j. Betsch, Maksim Kunitski, Qiying Song, Till Jahnke, Nora G. Kling, O. Herrwerth, Boris Bergues, Arne SenftlebenAbstract:We study triple-Ionization-induced, spatially asymmetric dissociation of N2 using angular streaking in an elliptically polarized laser pulse in conjunction with few-cycle pump-probe experiments. The kinetic-energyrelease dependent directional asymmetry in the ion sum-momentum distribution reflects the internuclear distance dependence of the fragmentation mechanism. Our results show that for 5‐35-fs near-infrared laser pulses with intensitiesreaching10 15 W/cm 2 ,chargeexchangebetweennucleiplaysaminorroleinthetripleIonizationofN2. We demonstrate that angular streaking provides a powerful tool for probing multielectron effects in strong-field Dissociative Ionization of small molecules.
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electron nuclear energy sharing in above threshold multiphoton Dissociative Ionization of h2
Physical Review Letters, 2013Co-Authors: Maksim Kunitski, Lars Bojer Madsen, M Pitzer, F Trinter, Ph L H Schmidt, T Jahnke, Maia Magrakvelidze, C B Madsen, Uwe Thumm, R. DörnerAbstract:We report experimental observation of the energy sharing between electron and nuclei in abovethreshold multiphoton Dissociative Ionization of H2 by strong laser fields. The absorbed photon energy is shared between the ejected electron and nuclei in a correlated fashion, resulting in multiple diagonal lines in their joint energy spectrum governed by the energy conservation of all fragment particles. Deposition of the photon energy to atoms and molecules is the primary step of the interactions of radiation with matter. The details of this deposition process, in particular how the photon energy is distributed among the subsystems and various internal degrees of freedom, determine all photon-induced chemical and physical dynamics. For the interaction with a strong laser field, this question of energy deposition gets even richer since it is well established that the energy of more photons than the minimal number required for Ionization can be absorbed. For atoms in a strong field, this leads to discrete peaks in the photoelectron spectrum that are spaced by the photon energy and referred to as ‘‘above-threshold Ionization’’ (ATI) [1]. For molecules the vibrational, rotational, and Dissociative motions of the nuclei provide a sink for the photon energy in addition to the electrons. This has been observed in single-photon Dissociative Ionization of molecules exposed to synchrotron radiation [2–4], where the photon energy is shared by the freed electrons and the nuclear fragments. For the molecular multiphoton case, rich ATI spectra of the freed electron [5–9], bond-softening-induced molecular Dissociative Ionization [10–15], and the imaging of internuclear distance using nuclear kinetic energy release spectra [16–19] have been reported. The correlation between the fragment ion and the electron energy has most recently been studied in numerical simulations for H 2 þ [20,21]. A nontrivial sharingof the absorbedphoton energy between the electron and nuclei in multiphoton Ionization of molecules was predicted and stimulated us to investigate this problem experimentally. Here, we report the experimental observation of the energy sharing between the emitted electron and nuclei from above-threshold multiphoton Dissociative Ionization of the simplest molecule H 2 by intense femtosecond laser pulses. Discrete numbers of absorbed photons can be identified by peaked diagonal lines in the joint energy spectrum (JES) of the coincidently measured electron and nuclei [20]. Since there is no direct coupling between the nuclei and the laser field for homonuclear diatomic molecules, the laser first couples to the electrons, and the electrons then couple to the nuclei. The energy taken by the nuclei therefore measures the correlation between the electrons and nuclei. Figure 1 shows a much simplified schematics of the process. By absorbing multiple photons (blue vertical arrows), the H2 molecule emits one electron and a nuclear wavepacket on the � þ (ground) state of H 2 þ is launched. It propagates on the � þ potential curve of H 2 þ .P art of this wavepacket already has sufficient energy to escape (direct pathway), while another part can be promoted to the Dissociative � þ potential curve by resonant absorption of one additional photon (one-photon pathway). In the multiphoton picture, the sum of the kinetic energy of the proton (Ep), hydrogen atom (EH), and electron (Ee) after the end of the laser pulse is given by