ABSTRACT: Sequential and direct two-photon double ionization (DI) of D2 molecule is studied experimentally and theoretically at a photon energy of 38.8 eV. Experimental and theoretical kinetic energy releases of D++D+ fragments, consisting of the contributions of sequential DI via the D2+(1ssg) state and direct DI via a virtual state, agree well with each other

Dörner, R.

Düsterer, S.

Ergler, Th.

Fischer, D.

Foucar, L.

Jiang, Y. H.

Kühnel, K. U.

Lüdemann, S.

Martín García, Fernando

Moshammer, R.

Plésiat, E.

Pérez Torres, Jhon Fredy

Rudenko, A.

Sanz Vicario, José Luis

Schröter, C. D.

Schöffler, M.

Titze, J.

Treusch, R.

Ullrich, J.

Zrost, K.

Journal of Physics Conference Series

English

Sequential and direct two-photon double ionization (DI) of D2 molecule is studied experimentally and theoretically at a photon energy of 38.8 eV. Experimental and theoretical kinetic energy releases of D++D+ fragments, consisting of the contributions of sequential DI via the D2+(1ssg) state and direct DI via a virtual state, agree well with each other

Jiang, Y.

Kühnel, K.

Ergler, T.

Pérez-Torres, J.

Martín, F.

Sanz-Vicario, L.

Schröter, C.

MPG.PuRe

Sequential and direct two-photon double ionization of D<sub>2</sub> at FLASH

Sequential and direct two-photon double ionization (DI) of D2 molecule is studied experimentally and
theoretically at a photon energy of 38.8 eV. Experimental and theoretical kinetic energy releases of D++D+
fragments, consisting of the contributions of sequential DI via the D2+(1ssg) state and direct DI via a virtual state,
agree well with each other

Kühnel, K.-U.

Max Planck Society eDoc Server

Sequential and direct two-photon double ionization of D2 at FLASH

Sequential and direct two-photon double ionization (DI) of D2 molecule is studied experimentally and theoretically at a photon energy of 38.8 eV. Experimental and theoretical kinetic energy releases of D++D+fragments, consisting of the contributions of sequential DI via the D2+(1sσg) state and direct DI via a virtual state, agree well with each other

Rudenko, Artem

Kuhnel, Kai Uwe

Ludemann, S.

Zrost, Karl

Fischer, Daniel

Perez-Torres, J.

Plesiat, E.

Martin, F.

Schoffler, Markus S.

Dorner, Reinhard

Sanz-Vicario, J. L.

Dusterer, S.

Schroter, Claus Dieter

Moshammer, Robert

Ullrich, Joachim Hermann

Missouri University of Science and Technology (Missouri S&T): Scholars' Mine

Missouri University of Science and Technology Scholars' Mine Physics Faculty Research & Creative Works Physics 01 Jan 2009 Sequential and Direct Two-Photon Double Ionization of D₂ at Flash Y. H. Jiang Artem Rudenko Kai Uwe Kuhnel Th. Ergler et. al. For a complete list of authors, see https://scholarsmine.mst.edu/phys_facwork/784 Follow this and additional works at: https://scholarsmine.mst.edu/phys_facwork  Part of the Physics Commons Recommended Citation "Sequential and Direct Two-Photon Double Ionization of D₂ at Flash," Journal of Physics: Conference Series, vol. 194, no. 3, Institute of Physics - IOP Publishing, Jan 2009. The definitive version is available at https://doi.org/10.1088/1742-6596/194/3/032057 This Article - Journal is brought to you for free and open access by Scholars' Mine. It has been accepted for inclusion in Physics Faculty Research & Creative Works by an authorized administrator of Scholars' Mine. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact scholarsmine@mst.edu. Journal of Physics: Conference SeriesSequential and direct two-photon double ionization of D2 at FLASHTo cite this article: Y H Jiang et al 2009 J. Phys.: Conf. Ser. 194 032057 View the article online for updates and enhancements.This content was downloaded from IP address 131.151.26.179 on 12/10/2018 at 17:47Sequential and direct two-photon double ionization of D2 at FLASH Y.H. Jiang1, A. Rudenko2, K.U. Kühnel1, Th. Ergler1, S. Lüdemann1, K. Zrost1, D. Fischer1, J. Pérez-Torres3, E. Plésiat3, F. Martín3, L. Foucar4, J. Titze4, M. Schöffler4, R. Dörner4, J. L. Sanz-Vicario5, S. Düsterer6, R. Treusch6, C. D. Schröter1, R. Moshammer1, J. Ullrich1,2,∗  1 Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany 2 Max-Planck Advanced Study Group at CFEL, 22607 Hamburg, Germany 3 Departamento de Química C-9, Universidad Autónoma de Madrid, 28049, Spain 4 Institut für Kernphysik, Universität Frankfurt, 60486 Frankfurt, Germany 5 Instituto de Física, Universidad de Antioquia, Medellín, Colombia; 6 DESY, 22607 Hamburg, Germany  Synopsis Sequential and direct two-photon double ionization (DI) of D2 molecule is studied experimentally and theoretically at a photon energy of 38.8 eV. Experimental and theoretical kinetic energy releases of D++D+ fragments, consisting of the contributions of sequential DI via the D2+(1sσg) state and direct DI via a virtual state, agree well with each other.       Two-photon double ionization (DI) of H2 or D2 is of fundamental interest for studies of electron-electron and electron-ion correlations [1, 2]. Free electron lasers, delivering coherent pulses of EUV-photons with femtosecond durations at unprecedented intensities, in combination with advanced multi-particle detection systems − a  reaction microscope [3] – open a new era exploring the dynamics of molecular ionization, dissociation, alignment, and nuclear wave packet propagation.  The measurements were performed at photon energies of 38.8±0.5 eV, with pulse durations of ≅30 fs, and intensities of I ≅ 1013 W/cm2 at FLASH. Ionic fragments produced by the interaction with the light-pulse are projected by means of an electric field onto time- and position-sensitive MCP detectors. From the measured time-of-flights and positions of each individual fragment the initial 3D momentum vectors are reconstructed.  We have performed two model calculations in the framework of the Franck-Condon approximation in which (i) the two electrons are directly ionized (direct mechanism) and (ii) the two electrons are treated as independent particles and the two photons are absorbed sequentially by each electron (sequential mechanism). The probabilities resulting from both calculations have been added incoherently. The kinetic energy release (KER) spectrum for coincident D++ D+ fragments as well as the angular distribution of the fragments (cosθ) as a function of KERs are plotted in Fig. 1(a) and (b), respectively. The experimental result is found to be well described by theoretical calculations in Fig. 1(b). The peak at EKER=10 eV is populated by sequential DI after nuclear wave-packet motion in the D2+(1sσg) state initiated by the first photon. Since the FEL pulse duration (~30 fs) is about four times longer than the vibration period (7~8 fs) of D2+(1sσg), populated by absorption of the first photon the nuclear wave packet is able to move to the outer classical turning points, where the second photon is absorbed with larger probability. Two different ionization processes, namely sequential DI occurring in the FC regime, when the nuclear wave packet had not moved significantly, and direct DI via a virtual state, both are responsible for forming the second peak at EKER=17.5 eV.    Fig.1. (a) angular distribution for the coincident fragments D++D+ and (b) KER spectra. θ is  angle between the molecular axis and the light polarization.  Surprisingly, neither the doubly excited states of D2 nor excited states of D2+ play a significant role. The reason is that more than 95% of one-photon ionization probability leads to the ground state of D2+.  References [1] J. Colgan et al., J. Phys. B 2008 41 085202 [2] F. Martín 2008 ICOMP, Heidelberg.  [3] Ullrich J et al 2003 Rep. Prog. Phys. 66 1463 ∗ E-mail: Joachim.Ullrich@mpi-hd.mpg.de XXVI International Conference on Photonic, Electronic and Atomic Collisions IOP PublishingJournal of Physics: Conference Series 194 (2009) 032057 doi:10.1088/1742-6596/194/3/032057c© 2009 IOP Publishing Ltd 1

Sequential and Direct Two-Photon Double Ionization of D₂ at Flash

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This content has been downloaded from IOPscience. Please scroll down to see the full text.Download details:IP Address: 200.24.16.228This content was downloaded on 24/01/2017 at 18:50Please note that terms and conditions apply.Sequential and direct two-photon double ionization of D2 at FLASHView the table of contents for this issue, or go to the journal homepage for more2009 J. Phys.: Conf. Ser. 194 032057(http://iopscience.iop.org/1742-6596/194/3/032057)Home Search Collections Journals About Contact us My IOPscienceYou may also be interested in:Pulse length effects in two-photon single and double ionization of helium by ultrashort laserpulsesA Palacios, T N Rescigno and C W McCurdyAngular distributions and correlations in sequential two-photon atomic double ionizationA N Grum-Grzhimailo, E V Gryzlova, S I Strakhova et al.Two-photon double ionization of He and Ne with intense VUV free-electron-laser pulsesA Rudenko, M Kurka, L Foucar et al.Double ionization of molecule H2 in intense ultrashort laser fieldsThu-Thuy Le and Ngoc-Ty NguyenConvergent close coupling calculations of two-photon double ionization of HeA S Kheifets, I A Ivanov and I BrayStrong field double ionization of Helium with ultra-short phase stabilized circularly polarizedlaser pulsesM S Schöffler, X Xie, S Roither et al.Direct three-photon triple ionization of Li and double ionization of Li+A Emmanouilidou, V Hakobyan and P LambropoulosPhotoelectron energy spectrum in `direct' two-photon double ionization of heliumM A Kornberg and P LambropoulosSequential and direct two-photon double ionization of D2 at FLASH Y.H. Jiang1, A. Rudenko2, K.U. Kühnel1, Th. Ergler1, S. Lüdemann1, K. Zrost1, D. Fischer1, J. Pérez-Torres3, E. Plésiat3, F. Martín3, L. Foucar4, J. Titze4, M. Schöffler4, R. Dörner4, J. L. Sanz-Vicario5, S. Düsterer6, R. Treusch6, C. D. Schröter1, R. Moshammer1, J. Ullrich1,2,∗  1 Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany 2 Max-Planck Advanced Study Group at CFEL, 22607 Hamburg, Germany 3 Departamento de Química C-9, Universidad Autónoma de Madrid, 28049, Spain 4 Institut für Kernphysik, Universität Frankfurt, 60486 Frankfurt, Germany 5 Instituto de Física, Universidad de Antioquia, Medellín, Colombia; 6 DESY, 22607 Hamburg, Germany  Synopsis Sequential and direct two-photon double ionization (DI) of D2 molecule is studied experimentally and theoretically at a photon energy of 38.8 eV. Experimental and theoretical kinetic energy releases of D++D+ fragments, consisting of the contributions of sequential DI via the D2+(1sσg) state and direct DI via a virtual state, agree well with each other.       Two-photon double ionization (DI) of H2 or D2 is of fundamental interest for studies of electron-electron and electron-ion correlations [1, 2]. Free electron lasers, delivering coherent pulses of EUV-photons with femtosecond durations at unprecedented intensities, in combination with advanced multi-particle detection systems − a  reaction microscope [3] – open a new era exploring the dynamics of molecular ionization, dissociation, alignment, and nuclear wave packet propagation.  The measurements were performed at photon energies of 38.8±0.5 eV, with pulse durations of ≅30 fs, and intensities of I ≅ 1013 W/cm2 at FLASH. Ionic fragments produced by the interaction with the light-pulse are projected by means of an electric field onto time- and position-sensitive MCP detectors. From the measured time-of-flights and positions of each individual fragment the initial 3D momentum vectors are reconstructed.  We have performed two model calculations in the framework of the Franck-Condon approximation in which (i) the two electrons are directly ionized (direct mechanism) and (ii) the two electrons are treated as independent particles and the two photons are absorbed sequentially by each electron (sequential mechanism). The probabilities resulting from both calculations have been added incoherently. The kinetic energy release (KER) spectrum for coincident D++ D+ fragments as well as the angular distribution of the fragments (cosθ) as a function of KERs are plotted in Fig. 1(a) and (b), respectively. The experimental result is found to be well described by theoretical calculations in Fig. 1(b). The peak at EKER=10 eV is populated by sequential DI after nuclear wave-packet motion in the D2+(1sσg) state initiated by the first photon. Since the FEL pulse duration (~30 fs) is about four times longer than the vibration period (7~8 fs) of D2+(1sσg), populated by absorption of the first photon the nuclear wave packet is able to move to the outer classical turning points, where the second photon is absorbed with larger probability. Two different ionization processes, namely sequential DI occurring in the FC regime, when the nuclear wave packet had not moved significantly, and direct DI via a virtual state, both are responsible for forming the second peak at EKER=17.5 eV.    Fig.1. (a) angular distribution for the coincident fragments D++D+ and (b) KER spectra. θ is  angle between the molecular axis and the light polarization.  Surprisingly, neither the doubly excited states of D2 nor excited states of D2+ play a significant role. The reason is that more than 95% of one-photon ionization probability leads to the ground state of D2+.  References [1] J. Colgan et al., J. Phys. B 2008 41 085202 [2] F. Martín 2008 ICOMP, Heidelberg.  [3] Ullrich J et al 2003 Rep. Prog. Phys. 66 1463 ∗ E-mail: Joachim.Ullrich@mpi-hd.mpg.de XXVI International Conference on Photonic, Electronic and Atomic Collisions IOP PublishingJournal of Physics: Conference Series 194 (2009) 032057 doi:10.1088/1742-6596/194/3/032057c© 2009 IOP Publishing Ltd 1

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Sequential and direct two-photon double ionization of D2 at FLASH

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