RT Journal Article
SR Electronic
T1 Tracing orbital images on ultrafast time scales
JF Science
JO Science
FD American Association for the Advancement of Science
SP eabf3286
DO 10.1126/science.abf3286
A1 Wallauer, R.
A1 Raths, M.
A1 Stallberg, K.
A1 Münster, L.
A1 Brandstetter, D.
A1 Yang, X.
A1 Güdde, J.
A1 Puschnig, P.
A1 Soubatch, S.
A1 Kumpf, C.
A1 Bocquet, F. C.
A1 Tautz, F. S.
A1 Höfer, U.
YR 2021
UL http://science.sciencemag.org/content/early/2021/02/17/science.abf3286.abstract
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 to observe ultrafast electron motion in time and space.