Dr. Daniel Keefer

Daniel Keefer graduated at LMU Munich, where he obtained a bachelor’s degree in chemistry and biochemistry (2012) and a master’s degree in chemistry (2014), including a research internship at Uppsala University. After his studies, he joined the group of Prof. Regina de Vivie-Riedle at LMU and obtained his PhD in theoretical chemistry in 2019, working on quantum molecular dynamics in complex environments and quantum optimal control. Daniel then moved to the University of California in Irvine for his postdoctoral studies, supported by a Feodor Lynen Research Fellowship of the Alexander von Humboldt foundation. In the group of Prof. Shaul Mukamel, he worked on the design and simulation of ultrafast X-ray spectroscopy for the probing of molecular photochemistry. In 2023, he joined the Max-Planck-Institute for Polymer Research in Mainz as a group leader in the Department of Molecular Spectroscopy. Daniel was awarded the ERC Starting Grant in 2023.

Research Interests

Elementary processes in nature, materials, and synthesis critically rely on ultrafast chemical transformations of individual molecules. Daniel’s research group simulates these transformations and their spectroscopic observables. Our goal is to design and extract signatures of the critical moments in nuclear and electronic dynamics that decisively influence photochemical outcomes. To this end we employ an advanced simulation protocol comprising (quantum) molecular dynamics, electronic structure theory, time-resolved spectroscopy, and quantum optimal control. Our simulations directly address and utilize cutting-edge experimental technology, such as X-ray free electron lasers, providing intense atto- and femtosecond (1 fs = 10-15 s) light fields to access the natural timescale of nuclear and electronic motion.

Recent publications

1.
Otterpohl, F.; Keefer, D.; Mukamel, S.; Thorwart, M.: Coherent Ultrafast Stimulated X-Ray Raman Spectroscopy of Dissipative Conical Intersections. Physical Review Letters 133 (9), 098001 (2024)
2.
Dodia, M.; Rouxel, J. R.; Cho, D.; Zhang, Y.; Keefer, D.; Bonn, M.; Nagata, Y.; Mukamel, S.: Water Solvent Reorganization upon Ultrafast Resonant Stimulated X-ray Raman Excitation of a Metalloporphyrin Dimer. Journal of Chemical Theory and Computation 20 (10), pp. 4254 - 4264 (2024)
3.
Jaiswal, V. K.; Montorsi, F.; Aleotti, F.; Segatta, F.; Keefer, D.; Mukamel, S.; Nenov, A.; Conti, I.; Garavelli, M.: Ultrafast photochemistry and electron-diffraction spectra in n → (3s) Rydberg excited cyclobutanone resolved at the multireference perturbative level. The Journal of Chemical Physics 160 (16), 164316 (2024)
4.
Cavaletto, S. M.; Nam, Y.; Rouxel, J. R.; Keefer, D.; Yong, H.; Mukamel, S.: Attosecond monitoring of nonadiabatic molecular dynamics by transient x-ray transmission spectroscopy. Journal of Chemical Theory and Computation 19 (8), pp. 2327 - 2339 (2023)
5.
Keefer, D.; Cavaletto, S. M.; Rouxel, J. R.; Garavelli, M.; Yong, H.; Mukamel, S.: Ultrafast x-ray probes of elementary molecular events. Annual Review of Physical Chemistry 74, pp. 73 - 97 (2023)
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