TY - JOUR AU - Mazza, Tommaso AU - Ilchen, Markus AU - Kiselev, M. D. AU - Gryzlova, E. V. AU - Baumann, Thomas AU - Boll, Rebecca AU - De Fanis, A. AU - Grychtol, P. AU - Montaño, J. AU - Music, Valerija AU - Ovcharenko, Y. AU - Rennhack, N. AU - Rivas, D. E. AU - Schmidt, Philipp AU - Wagner, Rene AU - Ziolkowski, Pawel AU - Berrah, N. AU - Erk, Benjamin AU - Johnsson, P. AU - Küstner-Wetekam, C. AU - Marder, L. AU - Martins, Michael AU - Ott, Christian AU - Pathak, Shashank AU - Pfeifer, Thomas AU - Rolles, Daniel AU - Zatsarinny, O. AU - Grum-Grzhimailo, A. N. AU - Meyer, Michael TI - Mapping Resonance Structures in Transient Core-Ionized Atoms JO - Physical review / X VL - 10 IS - 4 SN - 2160-3308 CY - College Park, Md. PB - APS M1 - PUBDB-2021-00009 SP - 041056 PY - 2020 AB - The nature of transient electronic states created by photoabsorption critically determines the dynamics of the subsequently evolving system. Here, we investigate K-shell photoionized atomic neon by absorbing a second photon within the Auger-decay lifetime of 2.4 fs using the European XFEL, a unique high-repetition-rate, wavelength-tunable x-ray free-electron laser. By high-resolution electron spectroscopy, we map out the transient Rydberg resonances unraveling the details of the subsequent decay of the hollow atom. So far, ultra-short-lived electronic transients, which are often inaccessible by experiments, were mainly inferred from theory but are now addressed by nonlinear x-ray absorption. The successful characterization of these resonances with femtosecond lifetimes provides the basis for a novel class of site-specific, nonlinear, and time-resolved studies with strong impact for a wide range of topics in physics and chemistry. LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000600284700002 DO - DOI:10.1103/PhysRevX.10.041056 UR - https://bib-pubdb1.desy.de/record/453555 ER -