29 November 2023
Photo: UHH, Marvin Reuner
The team tried to find out how photoelectron momentum microscopy can be used to make a movie of photo-induced motion of electrons in a molecule.
What are the capabilities offered by attosecond extreme ultraviolet and X-ray pulses for probing photon-induced electron dynamics in molecules? A theoretical study on this question by Daria Gorelova’s team was chosen for the Focus Days “Research Highlights in the Eyes of Editors”.
Editors of Physical Review A sift through countless papers and review them according to scientific standards. However, looking back at the past year, there are works that they particularly enjoyed publishing, and Daria Gorelova’s work is among them. The professor of physics at Universität Hamburg and researcher in the Cluster of Excellence “CUI: Advanced Imaging of Matter” was invited by Physical Review A to present the study from her group during this year’s Focus Days at the Atomic Physics Workshop at the Max Planck Institute for the Physics of Complex Systems in Dresden.
Understanding photo-induced dynamics in molecules and molecular systems is relevant for gaining insight into such processes as photosynthesis or solar-energy conversion into electricity in solar cells based on organic semiconductors. However, photo-induced processes are governed by electron motion that is extremely fast and takes place on an attosecond (10-18 sec) timescale.
Revealing the details of electronic motion within a molecule in real time
One technique for analyzing these processes is photoelectron momentum microscopy. A light pulse ionizes a sample, leading to the detachment of a photoelectron. The momentum distribution of the detached photoelectron encodes information about the shape of an orbital or a bond in the real space from which the electron was detached. So, photoelectrons detached by an attosecond light pulse can encode the state of the molecule at the instant of the measurement.
Photoelectron momentum distributions captured by attosecond photoelectron momentum microscopy can reveal details of electronic motion within a molecule in real time and with Angstrom (10-10 m) spatial resolution. “Attosecond photoelectron momentum microscopy has a big potential to become a novel technique to measure electronic motion,” Daria Gorelova says. “We hope that our theoretical study motivates further developments of time-resolved photoelectron momentum microscopy, bringing its time-resolution down to attosecond time region. Such a technique will provide novel capabilities to make electron movies in molecules.”
Marvin Reuner and Daria Popova-Gorelova
“Attosecond imaging of photoinduced dynamics in molecules using time-resolved photoelectron momentum microscopy”
Phys. Rev. A 107, 023101 (2023)