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28 results on '"Takanashi, Tsukasa"'

1. Resonant X-ray emission spectroscopy from broadband stochastic pulses at an X-ray free electron laser.

Author

Fuller, Franklin D, Loukianov, Anton, Takanashi, Tsukasa, You, Daehyun, Li, Yiwen, Ueda, Kiyoshi, Fransson, Thomas, Yabashi, Makina, Katayama, Tetsuo, Weng, Tsu-Chien, Alonso-Mori, Roberto, Bergmann, Uwe, Jan Kern, Yachandra, Vittal K, Wernet, Philippe, and Yano, Junko

Abstract

Hard X-ray spectroscopy is an element specific probe of electronic state, but signals are weak and require intense light to study low concentration samples. Free electron laser facilities offer the highest intensity X-rays of any available light source. The light produced at such facilities is stochastic, with spikey, broadband spectra that change drastically from shot to shot. Here, using aqueous ferrocyanide, we show that the resonant X-ray emission (RXES) spectrum can be inferred by correlating for each shot the fluorescence intensity from the sample with spectra of the fluctuating, self-amplified spontaneous emission (SASE) source. We obtain resolved narrow and chemically rich information in core-to-valence transitions of the pre-edge region at the Fe K-edge. Our approach avoids monochromatization, provides higher photon flux to the sample, and allows non-resonant signals like elastic scattering to be simultaneously recorded. The spectra obtained match well with spectra measured using a monochromator. We also show that inaccurate measurements of the stochastic light spectra reduce the measurement efficiency of our approach.

Published
2021

2. Ultrafast charge-transfer dynamics in a visible-light-excited iridium(III) terpyridine 2-phenylpyridine complex studied by femtosecond X-ray absorption spectroscopy

Author

Yamanaka, Ken-ichi, Sato, Kosuke, Sato, Shunsuke, Nozawa, Shunsuke, Lee, Sunghee, Fukaya, Ryo, Fukuzawa, Hironobu, You, Daehyun, Saito, Shu, Takanashi, Tsukasa, Katayama, Tetsuo, Togashi, Tadashi, Nonaka, Takamasa, Dohmae, Kazuhiko, Adachi, Shin-ichi, Ueda, Kiyoshi, Yabashi, Makina, Morikawa, Takeshi, and Asahi, Ryoji

Published
2023
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3. Real-time observation of X-ray-induced intramolecular and interatomic electronic decay in CH2I2

Author

Fukuzawa, Hironobu, Takanashi, Tsukasa, Kukk, Edwin, Motomura, Koji, Wada, Shin-ichi, Nagaya, Kiyonobu, Ito, Yuta, Nishiyama, Toshiyuki, Nicolas, Christophe, Kumagai, Yoshiaki, Iablonskyi, Denys, Mondal, Subhendu, Tachibana, Tetsuya, You, Daehyun, Yamada, Syuhei, Sakakibara, Yuta, Asa, Kazuki, Sato, Yuhiro, Sakai, Tsukasa, Matsunami, Kenji, Umemoto, Takayuki, Kariyazono, Kango, Kajimoto, Shinji, Sotome, Hikaru, Johnsson, Per, Schöffler, Markus S., Kastirke, Gregor, Kooser, Kuno, Liu, Xiao-Jing, Asavei, Theodor, Neagu, Liviu, Molodtsov, Serguei, Ochiai, Kohei, Kanno, Manabu, Yamazaki, Kaoru, Owada, Shigeki, Ogawa, Kanade, Katayama, Tetsuo, Togashi, Tadashi, Tono, Kensuke, Yabashi, Makina, Ghosh, Aryya, Gokhberg, Kirill, Cederbaum, Lorenz S., Kuleff, Alexander I., Fukumura, Hiroshi, Kishimoto, Naoki, Rudenko, Artem, Miron, Catalin, Kono, Hirohiko, and Ueda, Kiyoshi

Published
2019
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4. Electron spectroscopic study of nanoplasma formation triggered by intense soft x-ray pulses.

Author

Niozu, Akinobu, Yokono, Naomichi, Nishiyama, Toshiyuki, Fukuzawa, Hironobu, Sakurazawa, Tomohiro, Matsuda, Kazuhiro, Takanashi, Tsukasa, You, Daehyun, Li, Yiwen, Ono, Taishi, Gaumnitz, Thomas, Schöffler, Markus, Grundmann, Sven, Wada, Shin-ichi, Carpeggiani, Paolo, Xu, Wei Qing, Liu, Xiao Jing, Owada, Shigeki, Tono, Kensuke, and Togashi, Tadashi

Subjects
SOFT X rays, THERMAL electrons, ELECTRON emission, ELECTRON spectroscopy, ELECTRONS, FREE electron lasers, ULTRASHORT laser pulses
Abstract

Using electron spectroscopy, we investigated the nanoplasma formation process generated in xenon clusters by intense soft x-ray free electron laser (FEL) pulses. We found clear FEL intensity dependence of electron spectra. Multistep ionization and subsequent ionization frustration features are evident for the low FEL-intensity region, and the thermal electron emission emerges at the high FEL intensity. The present FEL intensity dependence of the electron spectra is well addressed by the frustration parameter introduced by Arbeiter and Fennel [New J. Phys. 13, 053022 (2011)]. [ABSTRACT FROM AUTHOR]

Published
2019
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5. Photo-ionization and fragmentation of Sc3N@C80 following excitation above the Sc K-edge.

Author

Obaid, Razib, Schnorr, Kirsten, Wolf, Thomas J. A., Takanashi, Tsukasa, Kling, Nora G., Kooser, Kuno, Nagaya, Kiyonobu, Wada, Shin-ichi, Fang, Li, Augustin, Sven, You, Daehyun, Campbell, Eleanor E. B., Fukuzawa, Hironobu, Schulz, Claus P., Ueda, Kiyoshi, Lablanquie, Pascal, Pfeifer, Thomas, Kukk, Edwin, and Berrah, Nora

Subjects
FULLERENES, HARD X-rays, DAUGHTER ions, CHARGE exchange, AUGER effect, ELECTRONIC probes, CHARGE transfer, PHASE transitions
Abstract

We have investigated the ionization and fragmentation of a metallo-endohedral fullerene, Sc3N@C80, using ultrashort (10 fs) x-ray pulses. Following selective ionization of a Sc (1s) electron (hν = 4.55 keV), an Auger cascade leads predominantly to either a vibrationally cold multiply charged parent molecule or multifragmentation of the carbon cage following a phase transition. In contrast to previous studies, no intermediate regime of C2 evaporation from the carbon cage is observed. A time-delayed, hard x-ray pulse (hν = 5.0 keV) was used to attempt to probe the electron transfer dynamics between the encapsulated Sc species and the carbon cage. A small but significant change in the intensity of Sc-containing fragment ions and coincidence counts for a delay of 100 fs compared to 0 fs, as well as an increase in the yield of small carbon fragment ions, may be indicative of incomplete charge transfer from the carbon cage on the sub-100 fs time scale. [ABSTRACT FROM AUTHOR]

Published
2019
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6. Probing gaseous molecular structure by molecular-frame photoelectron angular distributions.

Author

Fukuzawa, Hironobu, Yamada, Syuhei, Sakakibara, Yuta, Tachibana, Tetsuya, Ito, Yuta, Takanashi, Tsukasa, Nishiyama, Toshiyuki, Sakai, Tsukasa, Nagaya, Kiyonobu, Saito, Norio, Oura, Masaki, Stener, Mauro, Decleva, Piero, and Ueda, Kiyoshi

Subjects
PHOTOELECTRONS, MOLECULAR structure, MOLECULAR probes, TIME-dependent density functional theory, DEPENDENCY (Psychology)
Abstract

Carbon 1s photoelectron angular distributions of an iodomethane molecule were measured relative to the recoil-frame determined by the momentum correlation between I+ and C H 3 + at photoelectron energies of 3, 6.1, and 12 eV. The energy dependent behavior of the recoil-frame photoelectron angular distributions is reproduced reasonably well by the time-dependent density functional theory with B-spline methods. We discuss potential applications of the fully differential photoelectron angular distribution measurements in the molecular frame to three-dimensional molecular structural determinations identifying the directions and lengths of the bonds. [ABSTRACT FROM AUTHOR]

Published
2019
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7. Resonant X-ray emission spectroscopy from broadband stochastic pulses at an X-ray free electron laser

Author

Fuller, Franklin D., Loukianov, Anton, Takanashi, Tsukasa, You, Daehyun, Li, Yiwen, Ueda, Kiyoshi, Fransson, Thomas, Yabashi, Makina, Katayama, Tetsuo, Weng, Tsu-Chien, Alonso-Mori, Roberto, Bergmann, Uwe, Kern, Jan, Yachandra, Vittal K., Wernet, Philippe, Yano, Junko, Fuller, Franklin D., Loukianov, Anton, Takanashi, Tsukasa, You, Daehyun, Li, Yiwen, Ueda, Kiyoshi, Fransson, Thomas, Yabashi, Makina, Katayama, Tetsuo, Weng, Tsu-Chien, Alonso-Mori, Roberto, Bergmann, Uwe, Kern, Jan, Yachandra, Vittal K., Wernet, Philippe, and Yano, Junko

Abstract

X-ray absorption and X-ray free electron lasers are important tools to study chemical and structural dynamics, but spectral details like pre-edge features are inherently hard to detect. Here, the authors show that stochastic spectroscopy can yield similar spectral information to monochromatic spectroscopies, while increasing signal yield and reducing acquisition time. Hard X-ray spectroscopy is an element specific probe of electronic state, but signals are weak and require intense light to study low concentration samples. Free electron laser facilities offer the highest intensity X-rays of any available light source. The light produced at such facilities is stochastic, with spikey, broadband spectra that change drastically from shot to shot. Here, using aqueous ferrocyanide, we show that the resonant X-ray emission (RXES) spectrum can be inferred by correlating for each shot the fluorescence intensity from the sample with spectra of the fluctuating, self-amplified spontaneous emission (SASE) source. We obtain resolved narrow and chemically rich information in core-to-valence transitions of the pre-edge region at the Fe K-edge. Our approach avoids monochromatization, provides higher photon flux to the sample, and allows non-resonant signals like elastic scattering to be simultaneously recorded. The spectra obtained match well with spectra measured using a monochromator. We also show that inaccurate measurements of the stochastic light spectra reduce the measurement efficiency of our approach.

Published
2021
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8. Suppression of thermal nanoplasma emission in clusters strongly ionized by hard x-rays

Author

Kumagai, Yoshiaki, Jurek, Zoltan, Xu, Weiqing, Saxena, Vikrant, Fukuzawa, Hironobu, Motomura, Koji, Iablonskyi, Denys, Nagaya, Kiyonobu, Wada, Shin-ichi, Ito, Yuta, Takanashi, Tsukasa, Yamada, Shuhei, Sakakibara, Yuta, Hiraki, Toshiyuki Nishiyama, Umemoto, Takayuki, Patanen, Minna, Bozek, John D., Dancus, Ioan, Cernaianu, Mihail, Miron, Catalin, Bauer, Tobias, Mucke, Melanie, Kukk, Edwin, Owada, Shigeki, Togashi, Tadashi, Tono, Kensuke, Yabashi, Makina, Son, Sang-Kil, Ziaja, Beata, Santra, Robin, Ueda, Kiyoshi, Kumagai, Yoshiaki, Jurek, Zoltan, Xu, Weiqing, Saxena, Vikrant, Fukuzawa, Hironobu, Motomura, Koji, Iablonskyi, Denys, Nagaya, Kiyonobu, Wada, Shin-ichi, Ito, Yuta, Takanashi, Tsukasa, Yamada, Shuhei, Sakakibara, Yuta, Hiraki, Toshiyuki Nishiyama, Umemoto, Takayuki, Patanen, Minna, Bozek, John D., Dancus, Ioan, Cernaianu, Mihail, Miron, Catalin, Bauer, Tobias, Mucke, Melanie, Kukk, Edwin, Owada, Shigeki, Togashi, Tadashi, Tono, Kensuke, Yabashi, Makina, Son, Sang-Kil, Ziaja, Beata, Santra, Robin, and Ueda, Kiyoshi

Abstract

Using electron and ion spectroscopy, we studied the electron and nuclear dynamics in similar to 50 000-atom large krypton clusters, following excitation with an intense hard x-ray pulse. Beyond the single pulse experiment, we also present the results of a time-resolved, x-ray pump-near-infrared probe measurement that allows one to learn about the time evolution of the system. After core ionization of the atoms by x-ray photons, trapped Auger and secondary electrons form a nanoplasma in which the krypton ions are embedded, according to the already published scenario. While the ion data show expected features, the electron emission spectra miss the expected pump-probe delay-dependent enhancement except for a slight enhancement in the energy range below 2 eV. Theoretical simulations help to reveal that, due to the deep trapping potential of the ions during the long time expansion accompanied by electron-ion recombination, thermal emission from the transient nanoplasma becomes quenched.

Published
2021
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9. Suppression of thermal nanoplasma emission in clusters strongly ionized by hard x-rays

Author

Kumagai, Yoshiaki, primary, Jurek, Zoltan, additional, Xu, Weiqing, additional, Saxena, Vikrant, additional, Fukuzawa, Hironobu, additional, Motomura, Koji, additional, Iablonskyi, Denys, additional, Nagaya, Kiyonobu, additional, Wada, Shin-ichi, additional, Ito, Yuta, additional, Takanashi, Tsukasa, additional, Yamada, Shuhei, additional, Sakakibara, Yuta, additional, Hiraki, Toshiyuki Nishiyama, additional, Umemoto, Takayuki, additional, Patanen, Minna, additional, Bozek, John D, additional, Dancus, Ioan, additional, Cernaianu, Mihail, additional, Miron, Catalin, additional, Bauer, Tobias, additional, Mucke, Melanie, additional, Kukk, Edwin, additional, Owada, Shigeki, additional, Togashi, Tadashi, additional, Tono, Kensuke, additional, Yabashi, Makina, additional, Son, Sang-Kil, additional, Ziaja, Beata, additional, Santra, Robin, additional, and Ueda, Kiyoshi, additional

Published
2021
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11. Characterizing crystalline defects in single nanoparticles from angular correlations of single-shot diffracted X-rays

Author

Niozu, Akinobu, primary, Kumagai, Yoshiaki, additional, Nishiyama, Toshiyuki, additional, Fukuzawa, Hironobu, additional, Motomura, Koji, additional, Bucher, Maximilian, additional, Asa, Kazuki, additional, Sato, Yuhiro, additional, Ito, Yuta, additional, Takanashi, Tsukasa, additional, You, Daehyun, additional, Ono, Taishi, additional, Li, Yiwen, additional, Kukk, Edwin, additional, Miron, Catalin, additional, Neagu, Liviu, additional, Callegari, Carlo, additional, Di Fraia, Michele, additional, Rossi, Giorgio, additional, Galli, Davide E., additional, Pincelli, Tommaso, additional, Colombo, Alessandro, additional, Owada, Shigeki, additional, Tono, Kensuke, additional, Kameshima, Takashi, additional, Joti, Yasumasa, additional, Katayama, Tetsuo, additional, Togashi, Tadashi, additional, Yabashi, Makina, additional, Matsuda, Kazuhiro, additional, Nagaya, Kiyonobu, additional, Bostedt, Christoph, additional, and Ueda, Kiyoshi, additional

Published
2020
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12. Multi-particle momentum correlations extracted using covariance methods on multiple-ionization of diiodomethane molecules by soft-X-ray free-electron laser pulses

Author

You, Daehyun, primary, Fukuzawa, Hironobu, additional, Luo, Yu, additional, Saito, Shu, additional, Berholts, Marta, additional, Gaumnitz, Thomas, additional, Huttula, Marko, additional, Johnsson, Per, additional, Kishimoto, Naoki, additional, Myllynen, Hanna, additional, Nemer, Ahmad, additional, Niozu, Akinobu, additional, Patanen, Minna, additional, Pelimanni, Eetu, additional, Takanashi, Tsukasa, additional, Wada, Shin-ichi, additional, Yokono, Naomichi, additional, Owada, Shigeki, additional, Tono, Kensuke, additional, Yabashi, Makina, additional, Nagaya, Kiyonobu, additional, Kukk, Edwin, additional, and Ueda, Kiyoshi, additional

Published
2020
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13. Real-time observation of X-ray-induced intramolecular and interatomic electronic decay in CH2I2

Author

30273436, Fukuzawa, Hironobu, Takanashi, Tsukasa, Kukk, Edwin, Motomura, Koji, Wada, Shin-ichi, Nagaya, Kiyonobu, Ito, Yuta, Nishiyama, Toshiyuki, Nicolas, Christophe, Kumagai, Yoshiaki, Iablonskyi, Denys, Mondal, Subhendu, Tachibana, Tetsuya, You, Daehyun, Yamada, Syuhei, Sakakibara, Yuta, Asa, Kazuki, Sato, Yuhiro, Sakai, Tsukasa, Matsunami, Kenji, Umemoto, Takayuki, Kariyazono, Kango, Kajimoto, Shinji, Sotome, Hikaru, Johnsson, Per, Schöffler, Markus S., Kastirke, Gregor, Kooser, Kuno, Liu, Xiao-Jing, Asavei, Theodor, Neagu, Liviu, Molodtsov, Serguei, Ochiai, Kohei, Kanno, Manabu, Yamazaki, Kaoru, Owada, Shigeki, Ogawa, Kanade, Katayama, Tetsuo, Togashi, Tadashi, Tono, Kensuke, Yabashi, Makina, Ghosh, Aryya, Gokhberg, Kirill, Cederbaum, Lorenz S., Kuleff, Alexander I., Fukumura, Hiroshi, Kishimoto, Naoki, Rudenko, Artem, Miron, Catalin, Kono, Hirohiko, Ueda, Kiyoshi, 30273436, Fukuzawa, Hironobu, Takanashi, Tsukasa, Kukk, Edwin, Motomura, Koji, Wada, Shin-ichi, Nagaya, Kiyonobu, Ito, Yuta, Nishiyama, Toshiyuki, Nicolas, Christophe, Kumagai, Yoshiaki, Iablonskyi, Denys, Mondal, Subhendu, Tachibana, Tetsuya, You, Daehyun, Yamada, Syuhei, Sakakibara, Yuta, Asa, Kazuki, Sato, Yuhiro, Sakai, Tsukasa, Matsunami, Kenji, Umemoto, Takayuki, Kariyazono, Kango, Kajimoto, Shinji, Sotome, Hikaru, Johnsson, Per, Schöffler, Markus S., Kastirke, Gregor, Kooser, Kuno, Liu, Xiao-Jing, Asavei, Theodor, Neagu, Liviu, Molodtsov, Serguei, Ochiai, Kohei, Kanno, Manabu, Yamazaki, Kaoru, Owada, Shigeki, Ogawa, Kanade, Katayama, Tetsuo, Togashi, Tadashi, Tono, Kensuke, Yabashi, Makina, Ghosh, Aryya, Gokhberg, Kirill, Cederbaum, Lorenz S., Kuleff, Alexander I., Fukumura, Hiroshi, Kishimoto, Naoki, Rudenko, Artem, Miron, Catalin, Kono, Hirohiko, and Ueda, Kiyoshi

Abstract

The increasing availability of X-ray free-electron lasers (XFELs) has catalyzed the development of single-object structural determination and of structural dynamics tracking in real-time. Disentangling the molecular-level reactions triggered by the interaction with an XFEL pulse is a fundamental step towards developing such applications. Here we report real-time observations of XFEL-induced electronic decay via short-lived transient electronic states in the diiodomethane molecule, using a femtosecond near-infrared probe laser. We determine the lifetimes of the transient states populated during the XFEL-induced Auger cascades and find that multiply charged iodine ions are issued from short-lived (∼20 fs) transient states, whereas the singly charged ones originate from significantly longer-lived states (∼100 fs). We identify the mechanisms behind these different time scales: contrary to the short-lived transient states which relax by molecular Auger decay, the long-lived ones decay by an interatomic Coulombic decay between two iodine atoms, during the molecular fragmentation.

Published
2019

14. Ultrafast Structural Dynamics of Nanoparticles in Intense Laser Fields

Author

Nishiyama, Toshiyuki, primary, Kumagai, Yoshiaki, additional, Niozu, Akinobu, additional, Fukuzawa, Hironobu, additional, Motomura, Koji, additional, Bucher, Maximilian, additional, Ito, Yuta, additional, Takanashi, Tsukasa, additional, Asa, Kazuki, additional, Sato, Yuhiro, additional, You, Daehyun, additional, Li, Yiwen, additional, Ono, Taishi, additional, Kukk, Edwin, additional, Miron, Catalin, additional, Neagu, Liviu, additional, Callegari, Carlo, additional, Di Fraia, Michele, additional, Rossi, Giorgio, additional, Galli, Davide E., additional, Pincelli, Tommaso, additional, Colombo, Alessandro, additional, Kameshima, Takashi, additional, Joti, Yasumasa, additional, Hatsui, Takaki, additional, Owada, Shigeki, additional, Katayama, Tetsuo, additional, Togashi, Tadashi, additional, Tono, Kensuke, additional, Yabashi, Makina, additional, Matsuda, Kazuhiro, additional, Bostedt, Christoph, additional, Nagaya, Kiyonobu, additional, and Ueda, Kiyoshi, additional

Published
2019
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15. Photo-ionization and fragmentation of Sc3N@C80 following excitation above the Sc K-edge

Author

Obaid, Razib, primary, Schnorr, Kirsten, additional, Wolf, Thomas J. A., additional, Takanashi, Tsukasa, additional, Kling, Nora G., additional, Kooser, Kuno, additional, Nagaya, Kiyonobu, additional, Wada, Shin-ichi, additional, Fang, Li, additional, Augustin, Sven, additional, You, Daehyun, additional, Campbell, Eleanor E. B., additional, Fukuzawa, Hironobu, additional, Schulz, Claus P., additional, Ueda, Kiyoshi, additional, Lablanquie, Pascal, additional, Pfeifer, Thomas, additional, Kukk, Edwin, additional, and Berrah, Nora, additional

Published
2019
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17. Following the Birth of a Nanoplasma Produced by an Ultrashort Hard-X-Ray Laser in Xenon Clusters

Author

30273436, Kumagai, Yoshiaki, Fukuzawa, Hironobu, Motomura, Koji, Iablonskyi, Denys, Nagaya, Kiyonobu, Wada, Shin-ichi, Ito, Yuta, Takanashi, Tsukasa, Sakakibara, Yuta, You, Daehyun, Nishiyama, Toshiyuki, Asa, Kazuki, Sato, Yuhiro, Umemoto, Takayuki, Kariyazono, Kango, Kukk, Edwin, Kooser, Kuno, Nicolas, Christophe, Miron, Catalin, Asavei, Theodor, Neagu, Liviu, Schöffler, Markus S., Kastirke, Gregor, Liu, Xiao-jing, Owada, Shigeki, Katayama, Tetsuo, Togashi, Tadashi, Tono, Kensuke, Yabashi, Makina, Golubev, Nikolay V., Gokhberg, Kirill, Cederbaum, Lorenz S., Kuleff, Alexander I., Ueda, Kiyoshi, 30273436, Kumagai, Yoshiaki, Fukuzawa, Hironobu, Motomura, Koji, Iablonskyi, Denys, Nagaya, Kiyonobu, Wada, Shin-ichi, Ito, Yuta, Takanashi, Tsukasa, Sakakibara, Yuta, You, Daehyun, Nishiyama, Toshiyuki, Asa, Kazuki, Sato, Yuhiro, Umemoto, Takayuki, Kariyazono, Kango, Kukk, Edwin, Kooser, Kuno, Nicolas, Christophe, Miron, Catalin, Asavei, Theodor, Neagu, Liviu, Schöffler, Markus S., Kastirke, Gregor, Liu, Xiao-jing, Owada, Shigeki, Katayama, Tetsuo, Togashi, Tadashi, Tono, Kensuke, Yabashi, Makina, Golubev, Nikolay V., Gokhberg, Kirill, Cederbaum, Lorenz S., Kuleff, Alexander I., and Ueda, Kiyoshi

Abstract

X-ray free-electron lasers (XFELs) made available a new regime of x-ray intensities, revolutionizing the ultrafast structure determination and laying the foundations of the novel field of nonlinear x-ray optics. Although earlier studies revealed nanoplasma formation when an XFEL pulse interacts with any nanometer-scale matter, the formation process itself has never been decrypted and its timescale was unknown. Here we show that time-resolved ion yield measurements combined with a near-infrared laser probe reveal a surprisingly ultrafast population (∼ 12 fs), followed by a slower depopulation (∼ 250 fs) of highly excited states of atomic fragments generated in the process of XFEL-induced nanoplasma formation. Inelastic scattering of Auger electrons and interatomic Coulombic decay are suggested as the mechanisms populating and depopulating, respectively, these excited states. The observed response occurs within the typical x-ray pulse durations and affects x-ray scattering, thus providing key information on the foundations of x-ray imaging with XFELs.

Published
2018

19. Following the Birth of a Nanoplasma Produced by an Ultrashort Hard-X-Ray Laser in Xenon Clusters

Author

Kumagai, Yoshiaki, primary, Fukuzawa, Hironobu, additional, Motomura, Koji, additional, Iablonskyi, Denys, additional, Nagaya, Kiyonobu, additional, Wada, Shin-ichi, additional, Ito, Yuta, additional, Takanashi, Tsukasa, additional, Sakakibara, Yuta, additional, You, Daehyun, additional, Nishiyama, Toshiyuki, additional, Asa, Kazuki, additional, Sato, Yuhiro, additional, Umemoto, Takayuki, additional, Kariyazono, Kango, additional, Kukk, Edwin, additional, Kooser, Kuno, additional, Nicolas, Christophe, additional, Miron, Catalin, additional, Asavei, Theodor, additional, Neagu, Liviu, additional, Schöffler, Markus S., additional, Kastirke, Gregor, additional, Liu, Xiao-jing, additional, Owada, Shigeki, additional, Katayama, Tetsuo, additional, Togashi, Tadashi, additional, Tono, Kensuke, additional, Yabashi, Makina, additional, Golubev, Nikolay V., additional, Gokhberg, Kirill, additional, Cederbaum, Lorenz S., additional, Kuleff, Alexander I., additional, and Ueda, Kiyoshi, additional

Published
2018
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20. Application of Matched-Filter Concepts to Unbiased Selection of Data in Pump-Probe Experiments with Free Electron Lasers

Author

30273436, Callegari, Carlo, Takanashi, Tsukasa, Fukuzawa, Hironobu, Motomura, Koji, Iablonskyi, Denys, Kumagai, Yoshiaki, Mondal, Subhendu, Tachibana, Tetsuya, Nagaya, Kiyonobu, Nishiyama, Toshiyuki, Matsunami, Kenji, Johnsson, Per, Piseri, Paolo, Sansone, Giuseppe, Dubrouil, Antoine, Reduzzi, Maurizio, Carpeggiani, Paolo, Vozzi, Caterina, Devetta, Michele, Faccialà, Davide, Calegari, Francesca, Castrovilli, Mattea, Coreno, Marcello, Alagia, Michele, Schütte, Bernd, Berrah, Nora, Plekan, Oksana, Finetti, Paola, Ferrari, Eugenio, Prince, Kevin, Ueda, Kiyoshi, 30273436, Callegari, Carlo, Takanashi, Tsukasa, Fukuzawa, Hironobu, Motomura, Koji, Iablonskyi, Denys, Kumagai, Yoshiaki, Mondal, Subhendu, Tachibana, Tetsuya, Nagaya, Kiyonobu, Nishiyama, Toshiyuki, Matsunami, Kenji, Johnsson, Per, Piseri, Paolo, Sansone, Giuseppe, Dubrouil, Antoine, Reduzzi, Maurizio, Carpeggiani, Paolo, Vozzi, Caterina, Devetta, Michele, Faccialà, Davide, Calegari, Francesca, Castrovilli, Mattea, Coreno, Marcello, Alagia, Michele, Schütte, Bernd, Berrah, Nora, Plekan, Oksana, Finetti, Paola, Ferrari, Eugenio, Prince, Kevin, and Ueda, Kiyoshi

Abstract

Pump-probe experiments are commonly used at Free Electron Lasers (FEL) to elucidate the femtosecond dynamics of atoms, molecules, clusters, liquids and solids. Maximizing the signal-to-noise ratio of the measurements is often a primary need of the experiment, and the aggregation of repeated, rapid, scans of the pump-probe delay is preferable to a single long-lasting scan. The limited availability of beamtime makes it impractical to repeat measurements indiscriminately, and the large, rapid flow of single-shot data that need to be processed and aggregated into a dataset, makes it difficult to assess the quality of a measurement in real time. In post-analysis it is then necessary to devise unbiased criteria to select or reject datasets, and to assign the weight with which they enter the analysis. One such case was the measurement of the lifetime of Intermolecular Coulombic Decay in the weakly-bound neon dimer. We report on the method we used to accomplish this goal for the pump-probe delay scans that constitute the core of the measurement; namely we report on the use of simple auto- and cross-correlation techniques based on the general concept of “matched filter”. We are able to unambiguously assess the signal-to-noise ratio (SNR) of each scan, which then becomes the weight with which a scan enters the average of multiple scans. We also observe a clear gap in the values of SNR, and we discard all the scans below a SNR of 0.45. We are able to generate an average delay scan profile, suitable for further analysis: in our previous work we used it for comparison with theory. Here we argue that the method is sufficiently simple and devoid of human action to be applicable not only in post-analysis, but also for the real-time assessment of the quality of a dataset.

Published
2017

21. Evidence for Efficient Pathway to Produce Slow Electrons by Ground-state Dication in Clusters

Author

You, Daehyun, primary, Fukuzawa, Hironobu, additional, Sakakibara, Yuta, additional, Takanashi, Tsukasa, additional, Ito, Yuta, additional, Maliyar, Gianluigi G., additional, Motomura, Koji, additional, Nagaya, Kiyonobu, additional, Nishiyama, Toshiyuki, additional, Asa, Kazuki, additional, Sato, Yuhiro, additional, Saito, Norio, additional, Oura, Masaki, additional, Schöffler, Markus, additional, Kastirke, Gregor, additional, Hergenhahn, Uwe, additional, Stumpf, Vasili, additional, Gohkberg, Kirill, additional, Kuleff, Alexander I., additional, Cederbaum, Lorenz S., additional, and Ueda, Kiyoshi, additional

Published
2017
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22. Application of Matched-Filter Concepts to Unbiased Selection of Data in Pump-Probe Experiments with Free Electron Lasers

Author

Callegari, Carlo, primary, Takanashi, Tsukasa, additional, Fukuzawa, Hironobu, additional, Motomura, Koji, additional, Iablonskyi, Denys, additional, Kumagai, Yoshiaki, additional, Mondal, Subhendu, additional, Tachibana, Tetsuya, additional, Nagaya, Kiyonobu, additional, Nishiyama, Toshiyuki, additional, Matsunami, Kenji, additional, Johnsson, Per, additional, Piseri, Paolo, additional, Sansone, Giuseppe, additional, Dubrouil, Antoine, additional, Reduzzi, Maurizio, additional, Carpeggiani, Paolo, additional, Vozzi, Caterina, additional, Devetta, Michele, additional, Faccialà, Davide, additional, Calegari, Francesca, additional, Castrovilli, Mattea, additional, Coreno, Marcello, additional, Alagia, Michele, additional, Schütte, Bernd, additional, Berrah, Nora, additional, Plekan, Oksana, additional, Finetti, Paola, additional, Ferrari, Eugenio, additional, Prince, Kevin, additional, and Ueda, Kiyoshi, additional

Published
2017
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23. Ultrafast Coulomb explosion of a diiodomethane molecule induced by an X-ray free-electron laser pulse

Author

Takanashi, Tsukasa, primary, Nakamura, Kosuke, additional, Kukk, Edwin, additional, Motomura, Koji, additional, Fukuzawa, Hironobu, additional, Nagaya, Kiyonobu, additional, Wada, Shin-ichi, additional, Kumagai, Yoshiaki, additional, Iablonskyi, Denys, additional, Ito, Yuta, additional, Sakakibara, Yuta, additional, You, Daehyun, additional, Nishiyama, Toshiyuki, additional, Asa, Kazuki, additional, Sato, Yuhiro, additional, Umemoto, Takayuki, additional, Kariyazono, Kango, additional, Ochiai, Kohei, additional, Kanno, Manabu, additional, Yamazaki, Kaoru, additional, Kooser, Kuno, additional, Nicolas, Christophe, additional, Miron, Catalin, additional, Asavei, Theodor, additional, Neagu, Liviu, additional, Schöffler, Markus, additional, Kastirke, Gregor, additional, Liu, Xiao-Jing, additional, Rudenko, Artem, additional, Owada, Shigeki, additional, Katayama, Tetsuo, additional, Togashi, Tadashi, additional, Tono, Kensuke, additional, Yabashi, Makina, additional, Kono, Hirohiko, additional, and Ueda, Kiyoshi, additional

Published
2017
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24. Femtosecond Time-resolved Study on Nanoplasma Dynamics of Xenon Clusters Irradiated with High Intensity Hard X-rays at SACL

Author

Kumagai, Yoshiaki, primary, Fukuzawa, Hironobu, additional, Motomura, Koji, additional, Iablonskyi, Denis, additional, Nagaya, Kiyonobu, additional, Wada, Shin-ich, additional, Ito, Yuta, additional, Takanashi, Tsukasa, additional, Sakakibara, Yuta, additional, You, Daehyun, additional, Nishiyama, Toshiyuki, additional, Asa, Kazuki, additional, Sato, Yuhiro, additional, Umemoto, Takayuki, additional, Kariyazono, Kango, additional, Kukk, Edwin, additional, Kooser, Kuno, additional, Nicolas, Christophe, additional, Miron, Catalin, additional, Asavei, Theodor, additional, Neagu, Liviu, additional, Schöffler, Markus, additional, Kastirke, Gregor, additional, Liu, Xiao-jing, additional, Owada, Shigeki, additional, Katayama, Tetsuo, additional, Togashi, Tadashi, additional, Tono, Kensuke, additional, Yabashi, Makina, additional, Yao, Makoto, additional, and Ueda, Kiyoshi, additional

Published
2016
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27. Real-time observation of X-ray-induced intramolecular and interatomic electronic decay in CH2I2.

Author

Fukuzawa, Hironobu, Takanashi, Tsukasa, Kukk, Edwin, Motomura, Koji, Wada, Shin-ichi, Nagaya, Kiyonobu, Ito, Yuta, Nishiyama, Toshiyuki, Nicolas, Christophe, Kumagai, Yoshiaki, Iablonskyi, Denys, Mondal, Subhendu, Tachibana, Tetsuya, You, Daehyun, Yamada, Syuhei, Sakakibara, Yuta, Asa, Kazuki, Sato, Yuhiro, Sakai, Tsukasa, and Matsunami, Kenji

Abstract

The increasing availability of X-ray free-electron lasers (XFELs) has catalyzed the development of single-object structural determination and of structural dynamics tracking in real-time. Disentangling the molecular-level reactions triggered by the interaction with an XFEL pulse is a fundamental step towards developing such applications. Here we report real-time observations of XFEL-induced electronic decay via short-lived transient electronic states in the diiodomethane molecule, using a femtosecond near-infrared probe laser. We determine the lifetimes of the transient states populated during the XFEL-induced Auger cascades and find that multiply charged iodine ions are issued from short-lived (∼20 fs) transient states, whereas the singly charged ones originate from significantly longer-lived states (∼100 fs). We identify the mechanisms behind these different time scales: contrary to the short-lived transient states which relax by molecular Auger decay, the long-lived ones decay by an interatomic Coulombic decay between two iodine atoms, during the molecular fragmentation. Understanding strong X-ray induced phenomena is important for applications of X-ray free-electron laser imaging. Here, the authors show time-resolved measurements of X-ray free-electron laser induced electronic decay of CH2I2 molecule probed with NIR pulses and identify mechanisms behind different transient states lifetimes. [ABSTRACT FROM AUTHOR]

Published
2019
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28. Photo-ionization and fragmentation of Sc 3 N@C 80 following excitation above the Sc K-edge.

Author

Obaid R, Schnorr K, Wolf TJA, Takanashi T, Kling NG, Kooser K, Nagaya K, Wada SI, Fang L, Augustin S, You D, Campbell EEB, Fukuzawa H, Schulz CP, Ueda K, Lablanquie P, Pfeifer T, Kukk E, and Berrah N

Abstract

We have investigated the ionization and fragmentation of a metallo-endohedral fullerene, Sc 3 N@C 80 , using ultrashort (10 fs) x-ray pulses. Following selective ionization of a Sc (1s) electron (hν = 4.55 keV), an Auger cascade leads predominantly to either a vibrationally cold multiply charged parent molecule or multifragmentation of the carbon cage following a phase transition. In contrast to previous studies, no intermediate regime of C 2 evaporation from the carbon cage is observed. A time-delayed, hard x-ray pulse (hν = 5.0 keV) was used to attempt to probe the electron transfer dynamics between the encapsulated Sc species and the carbon cage. A small but significant change in the intensity of Sc-containing fragment ions and coincidence counts for a delay of 100 fs compared to 0 fs, as well as an increase in the yield of small carbon fragment ions, may be indicative of incomplete charge transfer from the carbon cage on the sub-100 fs time scale.

Published
2019
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