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Hasegawa H, Matsuda A, Morishita T, Madsen LB, Jensen F, Tolstikhin OI, Hishikawa A. Dissociative ionization and Coulomb explosion of CH 4 in two-color asymmetric intense laser fields. Phys Chem Chem Phys 2023; 25:25408-25419. [PMID: 37706318 DOI: 10.1039/d3cp02337k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Directional fragment ejection from a tetrahedral molecule CH4 in linearly polarized two-color (ω and 2ω) asymmetric intense laser fields (50 fs, 1.4 × 1014 W cm-2, 800 nm and 400 nm) has been studied by three-dimensional ion coincidence momentum imaging. The H+ fragment produced from dissociative ionization, CH4 → H+ + CH3 + e-, is preferentially ejected on the larger amplitude side of the laser electric fields. Comparison with theoretical predictions by weak-field asymptotic theory shows that the observed asymmetry can be understood by the orientation selective tunneling ionization from the triply degenerated highest occupied molecular orbital (1t2) of CH4. A similar directional ejection of H+ was also observed for the low kinetic energy components of the two-body Coulomb explosion, CH4 → H+ + CH3+ + 2e-. On the other hand, the fragment ejection in the opposite direction were observed for the high energy component, as well as H2+ produced from the Coulomb explosion CH4 → H2+ + CH2+ + 2e-. Possible origins of the characteristic fragmentation are discussed.
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Affiliation(s)
- H Hasegawa
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan.
| | - A Matsuda
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan.
| | - T Morishita
- Institute for Advanced Science, The University of Electro-Communications, 1-5-1 Chofu-ga-oka, Chofu-shi, Tokyo 182-8585, Japan
| | - L B Madsen
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - F Jensen
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
| | - O I Tolstikhin
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
| | - A Hishikawa
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan.
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan
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Das R, Pandey DK, Nimma V, P M, Bhardwaj P, Chandravanshi P, Shameem K M M, Singh DK, Kushawaha RK. Strong-field ionization of polyatomic molecules: ultrafast H atom migration and bond formation in the photodissociation of CH 3OH. Faraday Discuss 2021; 228:432-450. [PMID: 33576353 DOI: 10.1039/d0fd00129e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Strong-field ionization induces various complex phenomena like bond breaking, intramolecular hydrogen migration, and bond association in polyatomic molecules. The H-atom migration and bond formation in CH3OH induced by intense femtosecond laser pulses are investigated using a Velocity Map Imaging (VMI) spectrometer. Various laser parameters like intensity (1.5 × 1013 W cm-2-12.5 × 1013 W cm-2), pulse duration (29 fs and 195 fs), wavelength (800 nm and 1300 nm), and polarization (linear and circular) can serve as a quantum control for hydrogen migration and the yield of Hn+ (n = 1-3) ions which have been observed in this study. Further, in order to understand the ejection mechanism of the hydrogen molecular ions H2+ and H3+ from singly-ionized CH3OH, quantum chemical calculations were employed. The dissociation processes of CH3OH+ occurring by four dissociative channels to form CHO+ + H3, H3+ + CHO, CH2+ + H2O, and H2O+ + CH2 are studied. Using the combined approach of experiments and theory, we have successfully explained the mechanism of intramolecular hydrogen migration and predicted the dissociative channels of singly-ionized CH3OH.
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Affiliation(s)
- Rituparna Das
- Physical Research Laboratory, Ahmedabad, India. and Indian Institute of Technology, Gandhinagar, Gujarat 382355, India
| | - Deepak K Pandey
- Department of Physics, Institute of Infrastructure Technology Research and Management, Ahmedabad, 380026, India
| | | | - Madhusudhan P
- Physical Research Laboratory, Ahmedabad, India. and Indian Institute of Technology, Gandhinagar, Gujarat 382355, India
| | - Pranav Bhardwaj
- Physical Research Laboratory, Ahmedabad, India. and Indian Institute of Technology, Gandhinagar, Gujarat 382355, India
| | | | | | - Dheeraj K Singh
- Department of Physics, Institute of Infrastructure Technology Research and Management, Ahmedabad, 380026, India
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Hishikawa A, Matsuda A, Fushitani M. Ultrafast Reaction Imaging and Control by Ultrashort Intense Laser Pulses. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2020. [DOI: 10.1246/bcsj.20200158] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Akiyoshi Hishikawa
- Research Center for Materials Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Akitaka Matsuda
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Mizuho Fushitani
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
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Nairat M, Lozovoy VV, Dantus M. Order of Magnitude Dissociative Ionization Enhancement Observed for Pulses with High Order Dispersion. J Phys Chem A 2016; 120:8529-8536. [PMID: 27744700 DOI: 10.1021/acs.jpca.6b08659] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
While the interaction of atoms in strong fields is well understood, the same cannot be said about molecules. We consider how dissociative ionization of molecules depends on the quality of the femtosecond laser pulses, in particular, the presence of third- and fourth-order dispersion. We find that high-order dispersion (HOD) unexpectedly results in order-of-magnitude enhanced ion yields, along with the factor of 3 greater kinetic energy release compared to transform-limited pulses with equal peak intensities. The magnitude of these effects is not caused by increased pulse duration. We evaluate the role of pulse pedestals produced by HOD and other pulse shaping approaches, for a number of molecules including acetylene, methanol, methylene chloride, acetonitrile, toluene, and o-nitrotoluene, and discuss our findings in terms of processes such as prealignment, preionization, and bond softening. We conclude, based on the quasi-symmetric temporal dependence of the observed enhancements that cascade ionization is likely responsible for the large accumulation of charge prior to the ejection of energetic fragments along the laser polarization axis.
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Affiliation(s)
- Muath Nairat
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824, United States
| | - Vadim V Lozovoy
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824, United States
| | - Marcos Dantus
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
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Konar A, Shu Y, Lozovoy VV, Jackson JE, Levine BG, Dantus M. Polyatomic molecules under intense femtosecond laser irradiation. J Phys Chem A 2014; 118:11433-50. [PMID: 25314590 DOI: 10.1021/jp505498t] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Interaction of intense laser pulses with atoms and molecules is at the forefront of atomic, molecular, and optical physics. It is the gateway to powerful new tools that include above threshold ionization, high harmonic generation, electron diffraction, molecular tomography, and attosecond pulse generation. Intense laser pulses are ideal for probing and manipulating chemical bonding. Though the behavior of atoms in strong fields has been well studied, molecules under intense fields are not as well understood and current models have failed in certain important aspects. Molecules, as opposed to atoms, present confounding possibilities of nuclear and electronic motion upon excitation. The dynamics and fragmentation patterns in response to the laser field are structure sensitive; therefore, a molecule cannot simply be treated as a "bag of atoms" during field induced ionization. In this article we present a set of experiments and theoretical calculations exploring the behavior of a large collection of aryl alkyl ketones when irradiated with intense femtosecond pulses. Specifically, we consider to what extent molecules retain their molecular identity and properties under strong laser fields. Using time-of-flight mass spectrometry in conjunction with pump-probe techniques we study the dynamical behavior of these molecules, monitoring ion yield modulation caused by intramolecular motions post ionization. The set of molecules studied is further divided into smaller sets, sorted by type and position of functional groups. The pump-probe time-delay scans show that among positional isomers the variations in relative energies, which amount to only a few hundred millielectronvolts, influence the dynamical behavior of the molecules despite their having experienced such high fields (V/Å). High level ab initio quantum chemical calculations were performed to predict molecular dynamics along with single and multiphoton resonances in the neutral and ionic states. We propose the following model of strong-field ionization and subsequent fragmentation for polyatomic molecules: Single electron ionization occurs on a suboptical cycle time scale, and the electron carries away essentially all of the energy, leaving behind little internal energy in the cation. Subsequent fragmentation of the cation takes place as a result of further photon absorption modulated by one- and two-photon resonances, which provide sufficient energy to overcome the dissociation energy. The proposed hypothesis implies the loss of a photoelectron at a rate that is faster than intramolecular vibrational relaxation and is consistent with the observation of nonergodic photofragmentation of polyatomic molecules as well as experimental results from many other research groups on different molecules and with different pulse durations and wavelengths.
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Affiliation(s)
- Arkaprabha Konar
- Department of Chemistry and ‡Department of Physics and Astronomy, Michigan State University , East Lansing, Michigan 48824, United States
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Goswami T, Das DK, Goswami D. Controlling the femtosecond laser-driven transformation of dicyclopentadiene into cyclopentadiene. Chem Phys Lett 2013; 558:1-7. [PMID: 24098059 PMCID: PMC3790071 DOI: 10.1016/j.cplett.2012.10.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Dynamics of the chemical transformation of dicyclopentadiene into cyclopentadiene in a supersonic molecular beam is elucidated using femtosecond time-resolved degenerate pump-probe mass spectrometry. Control of this ultrafast chemical reaction is achieved by using linearly chirped frequency modulated pulses. We show that negatively chirped femtosecond laser pulses enhance the cyclopentadiene photo-product yield by an order of magnitude as compared to that of the unmodulated or the positively chirped pulses. This demonstrates that the phase structure of femtosecond laser pulse plays an important role in determining the outcome of a chemical reaction.
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Affiliation(s)
| | - Dipak K. Das
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Debabrata Goswami
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
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Itakura R, Hasegawa H, Kurosaki Y, Yokoyama A, Ohshima Y. Coherent Correlation between Nonadiabatic Rotational Excitation and Angle-Dependent Ionization of NO in Intense Laser Fields. J Phys Chem A 2010; 114:11202-9. [DOI: 10.1021/jp102840t] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Ryuji Itakura
- Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa, Kyoto, 619-0215, Japan, Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8585, Japan and SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan, and Quantum Beam Science Directorate, Tokai Research and Development Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Hirokazu Hasegawa
- Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa, Kyoto, 619-0215, Japan, Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8585, Japan and SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan, and Quantum Beam Science Directorate, Tokai Research and Development Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Yuzuru Kurosaki
- Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa, Kyoto, 619-0215, Japan, Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8585, Japan and SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan, and Quantum Beam Science Directorate, Tokai Research and Development Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Atsushi Yokoyama
- Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa, Kyoto, 619-0215, Japan, Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8585, Japan and SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan, and Quantum Beam Science Directorate, Tokai Research and Development Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Yasuhiro Ohshima
- Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai Kizugawa, Kyoto, 619-0215, Japan, Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8585, Japan and SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan, and Quantum Beam Science Directorate, Tokai Research and Development Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
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Goswami T, Karthick Kumar SK, Dutta A, Goswami D. Control of laser induced molecular fragmentation of n-propyl benzene using chirped femtosecond laser pulses. Chem Phys 2009; 360:47-52. [PMID: 19696899 PMCID: PMC2722903 DOI: 10.1016/j.chemphys.2009.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Accepted: 04/16/2009] [Indexed: 10/30/2022]
Abstract
We present the effect of chirping a femtosecond laser pulse on the fragmentation of n-propyl benzene. An enhancement of an order of magnitude for the relative yields of C3H3+ and C5H5+ in the case of negatively chirped pulses and C6H5+ in the case of positively chirped pulses with respect to the transform-limited pulse indicates that in some fragmentation channel, coherence of the laser field plays an important role. For the relative yield of all other heavier fragment ions, resulting from the interaction of the intense laser field with the molecule, there is no such enhancement effect with the sign of chirp, within experimental errors. The importance of the laser phase is further reinforced through a direct comparison of the fragmentation results with the second harmonic of the chirped laser pulse with identical bandwidth.
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Affiliation(s)
- Tapas Goswami
- Department of Chemistry, Indian Institute of Technology Kanpur, UP 208016, India
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Photoelectron–photoion coincidence momentum imaging for dissociative ionization of ethanol in intense laser fields. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.05.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Wavepacket Dynamics of Molecules in Intense Laser Fields. SPRINGER SERIES IN CHEMICAL PHYSICS 2009. [DOI: 10.1007/978-3-540-69143-3_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Lozovoy VV, Zhu X, Gunaratne TC, Harris DA, Shane JC, Dantus M. Control of Molecular Fragmentation Using Shaped Femtosecond Pulses. J Phys Chem A 2008; 112:3789-812. [DOI: 10.1021/jp071691p] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vadim V. Lozovoy
- Department of Chemistry and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824
| | - Xin Zhu
- Department of Chemistry and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824
| | - Tissa C. Gunaratne
- Department of Chemistry and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824
| | - D. Ahmasi Harris
- Department of Chemistry and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824
| | - Janelle C. Shane
- Department of Chemistry and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824
| | - Marcos Dantus
- Department of Chemistry and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824
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Yazawa H, Shioyama T, Suda Y, Yamanaka M, Kannari F, Itakura R, Yamanouchi K. Controlling the dissociative ionization of ethanol with 800 and 400nm two-color femtosecond laser pulses. J Chem Phys 2007; 127:124312. [PMID: 17902908 DOI: 10.1063/1.2780156] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ethanol molecules were irradiated with a pair of temporally overlapping ultrashort intense laser pulses (10(13)-10(14) Wcm(2)) with different colors of 400 and 800 nm, and the dissociative ionization processes have been investigated. The yield ratio of the C-O bond breaking with respect to the C-C bond breaking was varied in the range of 0.17-0.53 sensitively depending on the delay time between the two laser pulses, and the absolute value of the yield of the C-O bond breaking was found to be increased largely when the Fourier-transform limited 800 nm laser pulse overlaps the stretched 400 nm laser pulse, demonstrating an advantage of the two-color intense laser fields in controlling chemical bond breaking processes.
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Affiliation(s)
- H Yazawa
- Department of Electronics and Electrical Engineering, Faculty of Science and Technologies, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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Lu HF, Li FY, Lin CC, Nagaya K, Chao I, Lin S. The fragmentation of ethanol cation under an electric field: An ab initio/RRKM study. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.06.063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Yazawa H, Shioyama T, Suda Y, Kannari F, Itakura R, Yamanouchi K. Dissociative ionization of ethanol by 400nm femtosecond laser pulses. J Chem Phys 2006; 125:184311. [PMID: 17115756 DOI: 10.1063/1.2387177] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The dissociative ionization of ethanol in short-pulsed laser fields at approximately 400 nm is investigated. The yield ratio of the C-O bond breaking with respect to the C-C bond breaking increases sharply as the temporal width increases from 60 to 400 fs, and the yield ratio is two to three times as large as that at 800 nm in the entire pulse-width range of 60-580 fs. The enhancement of the C-O bond breaking of singly charged ethanol at 400 nm and the bond elongation prior to the Coulomb explosion of doubly charged ethanol occurring in the relatively weak light field intensity of 10(12)-10(13) W cm(2) is interpreted by the efficient light-induced coupling among the electronic states at the shorter wavelength of 400 nm. From the double pulse experiment, in which ethanol is irradiated with a pair of short pulses (<80 fs), the most efficient coupling occurs at Deltat=160 fs that is much earlier than Deltat=250 at 800 nm, where Deltat denotes the temporal separation of the two pulses, indicating that the nonadiabatic field-induced potential crossings of singly charged ethanol occurs much earlier at 400 nm than at 800 nm.
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Affiliation(s)
- H Yazawa
- Department of Electronics and Electrical Engineering, Faculty of Science and Technologies, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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