Freiburg 2024 – scientific programme

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MO: Fachverband Molekülphysik

MO 15: Spectroscopy of Metal Clusters

MO 15.2: Talk

Wednesday, March 13, 2024, 15:00–15:15, HS 3042

Ultrafast Dynamics of Mass-selected Neutral Cerium Clusters Probed by Femtosecond NeNePo Spectroscopy — Max Grellmann¹, Nikita Kavka², •Jiaye Jin¹, Roland Mitrić², and Knut R. Asmis¹ — ¹Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig — ²Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Germany

Cerium clusters have unique physical properties, making them a subject of current research. The studies on sizes-selected clusters isolated in the gas phase provides information on the inherent cluster properties in the absence of a perturbing environment. Here, we report our results on electronic-state-selected vibrational wave-packet dynamics for the mass-selected neutral cerium clusters (Ce₂₋₄) in a cryogenic ion trap probed by two-color femtosecond pump-probe spectroscopy involving the negative-neutral-positive excitation scheme (fs-NeNePo). High-level CASSCF calculations and quantum dynamic simulations are performed to disentangle the observed oscillatory nuclear wave-packet dynamics on the dense potential energy surface (PES) for the neutral Ce₂, which arises mainly from two electronic states containing superconfigurations in Π symmetry. Both of the fs-NeNePo spectra for Ce₃ and Ce₄ show coherent vibrational wave-packet dynamics that decay rapidly within 2 picoseconds, suggesting the presence of crossed PESs. These valuable results demonstrate complex electronic and vibrational structures of neutral cerium clusters and the potential of fs-NeNePo to study femtosecond dynamics of mass-selected, neutral and tag-free lanthanide clusters with high density of states.

Keywords: Ultrafast Dyanmics; Metal Clusters; Vibrational Wave Packet; Cerium; Electronic Structures