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X-ray spectroscopy of ultrafast-decaying core-excited ionic states in atomsтезисы доклада
- Авторы: ILCHEN M., MEYER M., KISELEV M., GRYZLOVA E., ZATSARINNY O., GRUM-GRZHIMAILO A., MAZZA T., BAUMANN T., BOLL R., De FANIS A., GRYCHTOL P., MONTANO J., MUSIC V., OVCHARENKO Y., RENNHACK N., RIVAS D., SCHMIDT P., WAGNER R., ZIOLKOWSKI P., BERRAH N., ERK B., JOHNSSON P., KÜSTNER-WETEKAM C., MARDER L., MARTINS M., OTT C., PFEIFER T., ROLLES D., PATHAK S.
- Сборник: Report of Abstracts Science@FELs 2020
- Тезисы
- Год издания: 2020
- Первая страница: 33
- Последняя страница: 33
- Аннотация: Highly intense X-ray pulses from X-ray free-electron lasers (XFELs) allow to study in the shortwavelength regime non-linear, photo-induced processes in atoms and molecules. These can includesequential and non-sequential multiphoton ionization and excitation processes. Sequential ionizationprocesses in the X-rays involve core-shells and occur in competition with ultrafast relaxation viaAuger emission; when the X-ray intensity is high enough, this competition becomes effective andthe population of transient highly excited ions exposed to the radiation becomes significant, sothat it is possible to perform a spectroscopic characterization on it. By using the intense pulsesfrom the SASE3 soft X-ray undulators at European XFEL, we could, for the first time, studythe core-hole excitation of transient, highly excited atoms by means of resonant Auger electronspectroscopy employing the Small Quantum Systems (SQS) instrument. Neon was ionized at the 1sshell and,depending on the photon energy, either sequentially ionized to Ne2+ 1s02s22p6 or excited todifferent Ne+ 1s02s22p6np states within the same fs X-ray pulse. Thanks to the extremely efficienttunability of the SASE3 undulator, it was possible to scan the photon energy across the 1s12s22p6 !1s02s22p6np resonances with photon energy steps of 1 eV (much smaller than the bandwidth). Theresulting Auger electron spectra were recorded by electron time-of-flight spectrometers. The resultsof these measurements are compared to previous studies of single- photon processes populatingthe same final states and with theoretical results based on R-matrix calculations. The comparisonof the experimental results with the theoretical model allow to address the relevance of shake-upprocesses in the resonant Auger decay pattern for the particular case of the double core hole excited1s02s22p6np ionic state in comparison to the neutral 1s12s22p6np. These results are benchmarkingthe performance of the SQS endstation at European XFEL and demonstrate the novel possibilitieswhich have been opened up in particular for investigations of non-linear phenomena and ultrafastdecaying transient states in the X-ray domain.
- Добавил в систему: Грызлова Елена Владимировна