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Biswas S, Tribedi LC. A recoil ion momentum spectrometer for probing ionization, e-capture, and capture-ionization induced molecular fragmentation dynamics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:123304. [PMID: 34972410 DOI: 10.1063/5.0068307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
The development of a recoil ion momentum spectrometer (RIMS) along with a post-collision projectile charge state analyzer (CSA) and its performance for carrying out studies of molecular fragmentation following direct ionization, electron-capture, and capture-ionization have been demonstrated here. This is a two-stage Wiley-McLaren type spectrometer with slight modification introduced by adding a lens to achieve higher momentum resolution as well as larger angular acceptance. Along with the time and position sensitive detector, it can measure all the three momentum components of singly charged recoil ions of energy up to 10 eV emitted in all directions. The CSA assembly is designed for separating out any neutral or singly or doubly charged post-collision projectiles typically of keV energy. The RIMS with initial trigger ("start") from CSA or an ionized electron can uniquely determine the dynamics of molecular fragmentation following different electron-capture or direct ionization events, respectively. To check the performance of the setup, we carried out an experimental study of the fragmentation of N2 molecules under the impact of 250 keV protons. Apart from the single-electron-capture channel, we could clearly identify three more capture-ionization channels, which lead to fragmentation. The essential features of the momentum distributions and the kinetic energy release distributions of all three fragmentation channels are discussed in detail. These results are compared with the findings from the ionization induced fragmentation experiments and with the available results from theoretical calculations as well as high resolution experiments. The branching ratios of these fragmentation channels are determined.
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Affiliation(s)
- Shubhadeep Biswas
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Lokesh C Tribedi
- Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
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2
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Bhattacharya D, Shamasundar KR, Emmanouilidou A. Potential Energy Curves of Molecular Nitrogen for Singly and Doubly Ionized States with Core and Valence Holes. J Phys Chem A 2021; 125:7778-7787. [PMID: 34477371 DOI: 10.1021/acs.jpca.1c04613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Theoretical description of potential energy curves (PECs) of molecular ions is essential for interpretation and prediction of coupled electron-nuclear dynamics following ionization of parent molecule. However, an accurate representation of these PECs for core or inner valence ionized state is nontrivial, especially at stretched geometries for double- or triple-bonded systems. In this work, we report PECs of singly and doubly ionized states of molecular nitrogen using state-of-the-art quantum chemical methods. The valence, inner valence, and core ionized states have been computed. A double-loop optimization scheme that separates the treatment of the core and the valence orbitals during the orbital optimization step of the multiconfiguration self-consistent field method has been implemented. This technique allows the energy to be converged to any desired ionized state with any number of core or inner-shell holes. The present work also compares the PECs obtained using both delocalized and localized sets of orbitals for the core hole states. The PECs of a number of singly and doubly ionized valence states have also been computed and compared with previous studies. The computed PECs reported here are expected to be of importance for future studies to understand the interplay between photoionization and Auger spectra during the breakup of molecular nitrogen when interacting with intense free electron lasers.
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Affiliation(s)
- Debarati Bhattacharya
- Department of Physics and Astrophysics, University College London, Gower Street, London WC1E 6BT, U.K
| | - K R Shamasundar
- Indian Institute of Science Education and Research, Mohali, Sector 81, SAS Nagar, Mohali 140306, India
| | - Agapi Emmanouilidou
- Department of Physics and Astrophysics, University College London, Gower Street, London WC1E 6BT, U.K
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3
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Zhang J, Li Z, Yang Y. Multi-ionization of the Cl 2 molecule in the near-infrared femtosecond laser field. RSC Adv 2019; 10:332-337. [PMID: 35492539 PMCID: PMC9048264 DOI: 10.1039/c9ra06746a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/02/2019] [Indexed: 11/26/2022] Open
Abstract
The multi-electron ionization and subsequent dissociation of the Cl2 molecule in a near-infrared femtosecond laser field was investigated via the dc-sliced ion imaging technique. The single charged molecular ions, Cl2+, dissociate from two excited states, 2Πu and 2Σg+, with the electrons ionized from the HOMO−1 and HOMO−2 orbital, respectively. For the multi-charged molecular ions, Cl2n+ (n = 2–8), our results showed that the stretch of the inter-nuclear distance benefitted the ionization of the electrons to produce highly-charged molecular ions. In addition, compared with the traditional charge resonance enhanced ionization (CREI) model, the critical distance (Rc) for the Cl2 molecule in our experiment was a short range that depended on the charge state rather than a single point. The multi-electron ionization and subsequent dissociation of the Cl2 molecule in a near-infrared femtosecond laser field was investigated via the dc-sliced ion imaging technique.![]()
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Affiliation(s)
- Jian Zhang
- Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University Shanghai 201620 China
| | - Zhipeng Li
- Department of Physics, State Key Laboratory of Precision Spectroscopy, East China Normal University Shanghai 200062 People's Republic of China
| | - Yan Yang
- Department of Physics, State Key Laboratory of Precision Spectroscopy, East China Normal University Shanghai 200062 People's Republic of China
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Engberg DLJ, Johnson LJS, Jensen J, Thuvander M, Hultman L. Resolving mass spectral overlaps in atom probe tomography by isotopic substitutions - case of TiSi 15N. Ultramicroscopy 2017; 184:51-60. [PMID: 28850866 DOI: 10.1016/j.ultramic.2017.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 08/02/2017] [Accepted: 08/10/2017] [Indexed: 11/17/2022]
Abstract
Mass spectral overlaps in atom probe tomography (APT) analyses of complex compounds typically limit the identification of elements and microstructural analysis of a material. This study concerns the TiSiN system, chosen because of severe mass-to-charge-state ratio overlaps of the 14N+ and 28Si2+ peaks as well as the 14N2+ and 28Si+ peaks. By substituting 14N with 15N, mass spectrum peaks generated by ions composed of one or more N atoms will be shifted toward higher mass-to-charge-state ratios, thereby enabling the separation of N from the predominant Si isotope. We thus resolve thermodynamically driven Si segregation on the nanometer scale in cubic phase Ti1-xSix15N thin films for Si contents 0.08 ≤ x ≤ 0.19 by APT, as corroborated by transmission electron microscopy. The APT analysis yields a composition determination that is in good agreement with energy dispersive X-ray spectroscopy and elastic recoil detection analyses. Additionally, a method for determining good voxel sizes for visualizing small-scale fluctuations is presented and demonstrated for the TiSiN system.
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Affiliation(s)
- David L J Engberg
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden.
| | | | - Jens Jensen
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden
| | - Mattias Thuvander
- Department of Physics, Chalmers University of Technology, Göteborg SE-412 96, Sweden
| | - Lars Hultman
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden
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5
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Jochim B, Siemering R, Zohrabi M, Voznyuk O, Mahowald JB, Schmitz DG, Betsch KJ, Berry B, Severt T, Kling NG, Burwitz TG, Carnes KD, Kling MF, Ben-Itzhak I, Wells E, de Vivie-Riedle R. The importance of Rydberg orbitals in dissociative ionization of small hydrocarbon molecules in intense laser fields. Sci Rep 2017; 7:4441. [PMID: 28667335 PMCID: PMC5493692 DOI: 10.1038/s41598-017-04638-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 05/18/2017] [Indexed: 11/10/2022] Open
Abstract
Much of our intuition about strong-field processes is built upon studies of diatomic molecules, which typically have electronic states that are relatively well separated in energy. In polyatomic molecules, however, the electronic states are closer together, leading to more complex interactions. A combined experimental and theoretical investigation of strong-field ionization followed by hydrogen elimination in the hydrocarbon series C2D2, C2D4 and C2D6 reveals that the photofragment angular distributions can only be understood when the field-dressed orbitals rather than the field-free orbitals are considered. Our measured angular distributions and intensity dependence show that these field-dressed orbitals can have strong Rydberg character for certain orientations of the molecule relative to the laser polarization and that they may contribute significantly to the hydrogen elimination dissociative ionization yield. These findings suggest that Rydberg contributions to field-dressed orbitals should be routinely considered when studying polyatomic molecules in intense laser fields.
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Affiliation(s)
- Bethany Jochim
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - R Siemering
- Department für Chemie, Ludwig-Maximilians-Universität München, Butenandt-Strasse 11, D-81377, München, Germany
| | - M Zohrabi
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - O Voznyuk
- Department of Physics, Augustana University, Sioux Falls, SD 57197, USA
| | - J B Mahowald
- Department of Physics, Augustana University, Sioux Falls, SD 57197, USA
| | - D G Schmitz
- Department of Physics, Augustana University, Sioux Falls, SD 57197, USA
| | - K J Betsch
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Ben Berry
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - T Severt
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Nora G Kling
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA.,Department für Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, D-85748, Garching, Germany
| | - T G Burwitz
- Department of Physics, Augustana University, Sioux Falls, SD 57197, USA
| | - K D Carnes
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - M F Kling
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA.,Department für Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, D-85748, Garching, Germany
| | - I Ben-Itzhak
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - E Wells
- Department of Physics, Augustana University, Sioux Falls, SD 57197, USA.
| | - R de Vivie-Riedle
- Department für Chemie, Ludwig-Maximilians-Universität München, Butenandt-Strasse 11, D-81377, München, Germany.
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Khan A, Tribedi LC, Misra D. A recoil ion momentum spectrometer for molecular and atomic fragmentation studies. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:043105. [PMID: 25933839 DOI: 10.1063/1.4916680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the development and performance studies of a newly built recoil ion momentum spectrometer for the study of atomic and molecular fragmentation dynamics in gas phase upon the impact of charged particles and photons. The present design is a two-stage Wiley-McLaren type spectrometer which satisfies both time and velocity focusing conditions and is capable of measuring singly charged ionic fragments up-to 13 eV in all directions. An electrostatic lens has been introduced in order to achieve velocity imaging. Effects of the lens on time-of-flight as well as on the position have been investigated in detail, both, by simulation and in experiment. We have used 120 keV proton beam on molecular nitrogen gas target. Complete momentum distributions and kinetic energy release distributions have been derived from the measured position and time-of-flight spectra. Along with this, the kinetic energy release spectra of fragmentation of doubly ionized nitrogen molecule upon various projectile impacts are presented.
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Affiliation(s)
- Arnab Khan
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Lokesh C Tribedi
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Deepankar Misra
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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Xie X, Doblhoff-Dier K, Xu H, Roither S, Schöffler MS, Kartashov D, Erattupuzha S, Rathje T, Paulus GG, Yamanouchi K, Baltuška A, Gräfe S, Kitzler M. Selective control over fragmentation reactions in polyatomic molecules using impulsive laser alignment. PHYSICAL REVIEW LETTERS 2014; 112:163003. [PMID: 24815647 DOI: 10.1103/physrevlett.112.163003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Indexed: 06/03/2023]
Abstract
We investigate the possibility of using molecular alignment for controlling the relative probability of individual reaction pathways in polyatomic molecules initiated by electronic processes on the few-femtosecond time scale. Using acetylene as an example, it is shown that aligning the molecular axis with respect to the polarization direction of the ionizing laser pulse does not only allow us to enhance or suppress the overall fragmentation yield of a certain fragmentation channel but, more importantly, to determine the relative probability of individual reaction pathways starting from the same parent molecular ion. We show that the achieved control over dissociation or isomerization pathways along specific nuclear degrees of freedom is based on a controlled population of associated excited dissociative electronic states in the molecular ion due to relatively enhanced ionization contributions from inner valence orbitals.
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Affiliation(s)
- Xinhua Xie
- Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria
| | - Katharina Doblhoff-Dier
- Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna, Austria and Institute for Physical Chemistry, Friedrich-Schiller University Jena, D-07743 Jena, Germany
| | - Huailiang Xu
- Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria and State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Stefan Roither
- Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria
| | - Markus S Schöffler
- Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria
| | - Daniil Kartashov
- Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria
| | - Sonia Erattupuzha
- Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria
| | - Tim Rathje
- Institute of Optics and Quantum Electronics, Friedrich-Schiller-University Jena, D-07743 Jena, Germany
| | - Gerhard G Paulus
- Institute of Optics and Quantum Electronics, Friedrich-Schiller-University Jena, D-07743 Jena, Germany and Helmholtz Institute Jena, D-07743 Jena, Germany
| | - Kaoru Yamanouchi
- Department of Chemistry, School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Andrius Baltuška
- Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria
| | - Stefanie Gräfe
- Institute for Physical Chemistry, Friedrich-Schiller University Jena, D-07743 Jena, Germany and Abbe Center of Photonics, Friedrich-Schiller-University Jena, D-07743 Jena, Germany
| | - Markus Kitzler
- Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria
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Pandey A, Bapat B, Shamasundar KR. Charge symmetric dissociation of doubly ionized N2 and CO molecules. J Chem Phys 2014; 140:034319. [PMID: 25669391 DOI: 10.1063/1.4861665] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report a comparative study of the features in dissociative double ionization by high energy electron impact of N2 and CO molecules. The ratio of cross-section of charge symmetric dissociative ionization to non-dissociative ionization (CSD-to-ND ratio) and the kinetic energy release (KER) spectra of dissociation are experimentally measured and carefully corrected for various ion transmission losses and detector inefficiencies. Given that the double ionization cross sections of these iso-electronic diatomics are very similar, the large difference in the CSD-to-ND ratios must be attributable to the differences in the evolution dynamics of the dications. To understand these differences, potential energy curves (PECs) of dications have been computed using multi-reference configuration interaction method. The Franck-Condon factors and tunneling life times of vibrational levels of dications have also been computed. While the KER spectrum of N2 (++) can be readily explained by considering dissociation via repulsive states and tunneling of meta-stable states, indirect dissociation processes such as predissociation and autoionization have to be taken into account to understand the major features of the KER spectrum of CO(++). Direct and indirect processes identified on the basis of the PECs and experimental KER spectra also provide insights into the differences in the CSD-to-ND ratios.
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Affiliation(s)
- A Pandey
- Physical Research Laboratory, Ahmedabad 380009, India
| | - B Bapat
- Physical Research Laboratory, Ahmedabad 380009, India
| | - K R Shamasundar
- Indian Institute of Science Education and Research, Mohali, Sector 81, SAS Nagar 140306, India
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9
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Bull JN, Lee JWL, Vallance C. Quantification of ions with identical mass-to-charge (m/z) ratios by velocity-map imaging mass spectrometry. Phys Chem Chem Phys 2013; 15:13796-800. [DOI: 10.1039/c3cp52219a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Wu C, Yang Y, Wu Z, Chen B, Dong H, Liu X, Deng Y, Liu H, Liu Y, Gong Q. Coulomb explosion of nitrogen and oxygen molecules through non-Coulombic states. Phys Chem Chem Phys 2011; 13:18398-408. [DOI: 10.1039/c1cp21345h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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