Ultrafast electronic dynamics in Helium nanodroplets studied by femtosecond time-resolved EUV photoelectron imaging |
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| Oliver Gessner | |
| Lawrence Berkeley National Laboratory | |
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The emerging field of ultrafast x-ray science is at a point at which its true potential for revealing electronic and structural dynamics in chemical and material sciences can be demonstrated. In particular, the study of complex systems will provide critical benchmarks for the transition from a specialists’ discipline to a widely-used tool. We have performed the first femtosecond EUV-pump, IR-probe experiment to study the photoionization dynamics of pure Helium nanodroplets below the atomic Helium IP. The droplets are comprised of thousands up to millions of atoms at a temperature of ~0.4 K. The superfluid clusters constitute a unique cryogenic matrix for the creation, isolation and spectroscopy of regular and exotic species, such as free radicals and molecules in high-spin states. Using femtosecond time-resolved photoelectron velocity-map imaging spectroscopy we have monitored the electronic relaxation dynamics of Helium droplets from the initial EUV excitation to the emergence of both neutral and charged products in real-time. |