Gessner Group @ Berkeley Lab

At the Forefront of Ultrafast X-ray Science

Our group explores ultrafast dynamics in molecules, clusters, and interfacial systems by a variety of state-of-the-art time-resolved XUV and X-ray spectroscopy as well as X-ray and electron imaging techniques. We strive to provide the most detailed understanding possible of the atomic-scale couplings, correlations and dynamics that govern collective behavior in atomic clusters, chemical transformations in molecules, and solar light harvesting processes in molecular and condensed phase systems. Our experiments reach sensitivities on the level of single electrons, atoms, and molecules, and cover temporal scales ranging from femtoseconds to microseconds. We employ laboratory based femtosecond XUV transient absorption, XUV photoelectron and ion imaging, X-ray free electron laser (X-FEL) and synchrotron based time-resolved X-ray spectroscopy and coherent diffractive imaging techniques, as well as ultrafast electron diffraction (UED) to study ultrafast reaction dynamics in molecules, energy and charge transfer dynamics at interfaces relevant for solar light harvesting applications, as well as the fundamental dynamics underlying the coupled and correlated motion in ground state, excited state, and highly ionized atomic clusters.

Working across boundaries of a variety of scientific disciplines, our group is a lively mixture of chemists and physicists with diverse backgrounds and origins, joined by their excitement for science and the knowledge that our team's diversity is key to our successes. Together with our international collaborators, we push the boundaries of knowledge in an environment fostered by mutual respect, personal growth, and a shared passion for scientific excellence.

More details of our research projects can be found here, our list of publications can be found here.

We frequently have openings for internships, graduate projects, and postdoctoral research opportunities. Feel free to contact us.

Recent News

Successful Picosecond Time-Resolved Ambient-Pressure X-ray Photoelectron Spectroscopy campaign at the ALS

Smiling faces after our team successfully completed the first picosecond time-resolved ambient pressure XPS experiment on photoinduced charge-transfer dynamics in a nanoplasmonic solar light harvesting system at the Advanced Light Source. Many thanks to the ALS staff for all their support!

Anisotropic Nanoplasma Dynamics work published in Physical Review Letters

A big thank you to all our collaborators from around the globe for making this possible, and congratulations to Camila on achieving this exceptional feat in the world of ultrafast X-ray imaging.

UXSS 2022 at SLAC National Accelerator Laboratory

Zach and Sahan joined the Ultrafast X-ray Summer School 2022, a 4 day workshop that introduces students and postdocs to the opportunities and ultrafast science available at X-ray Free Electron Lasers (FELs), such as LCLS. 

Selected Recent Publications