Article published in Nature Photonics.
Tracking electron motion in molecules is the key to understanding and controlling chemical transformations. Contemporary techniques in attosecond science are able to generate and trace the consequences of this motion in real time, but not in real space. Scanning tunnelling microscopy, on the other hand, can locally probe the valence electron density in molecules, but cannot alone provide dynamical information at this ultrafast timescale. Here we show that, by combining scanning tunnelling microscopy and attosecond technologies, quantum electronic coherences induced in molecules by <6-fs-long carrier-envelope-phase-stable near-infrared laser pulses can be directly visualized at ångström-scale spatial and subfemtosecond temporal resolutions. We demonstrate concurrent real-space and -time imaging of coherences involving the valence orbitals of perylenetetracarboxylic dianhydride molecules, and full control over the population of the involved orbitals. This approach opens the way to the unambiguous observation and manipulation of electron dynamics in complex molecular systems.
Acknowledgements: The research leading to this work has been carried out within the framework of the COST Action CA18222 (AttoChem), funded by the European Cooperation in Science and Technology (www.cost.eu). It has been partially funded by MCIN/ AEI /10.13039/501100011033 (grant ref. PID2019-105458RB-I00) and the Comunidad de Madrid (project Y2018/NMT-5028, FULMATEN-CM, co-funded at 50% by the European Social Fund of the Community of Madrid). [Full article]