TY - JOUR AU - Wallauer, R. AU - Raths, M. AU - Stallberg, K. AU - Münster, L. AU - Brandstetter, D. AU - Yang, X. AU - Güdde, J. AU - Puschnig, P. AU - Soubatch, S. AU - Kumpf, C. AU - Bocquet, F. C. AU - Tautz, F. S. AU - Höfer, U. TI - Tracing orbital images on ultrafast time scales JO - Science / Science now VL - 371 IS - 6533 SN - 1095-9203 CY - Washington, DC PB - Assoc.73085 M1 - FZJ-2021-01342 SP - 1056 - 1059 PY - 2021 AB - Frontier orbitals determine fundamental molecular properties such as chemical reactivities. Although electron distributions of occupied orbitals can be imaged in momentum space by photoemission tomography, it has so far been impossible to follow the momentum-space dynamics of a molecular orbital in time, for example, through an excitation or a chemical reaction. Here, we combined time-resolved photoemission using high laser harmonics and a momentum microscope to establish a tomographic, femtosecond pump-probe experiment of unoccupied molecular orbitals. We measured the full momentum-space distribution of transiently excited electrons, connecting their excited-state dynamics to real-space excitation pathways. Because in molecules this distribution is closely linked to orbital shapes, our experiment may, in the future, offer the possibility of observing ultrafast electron motion in time and space. LB - PUB:(DE-HGF)16 C6 - 33602865 UR - <Go to ISI:>//WOS:000625876100056 DO - DOI:10.1126/science.abf3286 UR - https://juser.fz-juelich.de/record/891059 ER -