@article{MedinaLagdsmandBenLtaiefetal.2023, author = {Medina, Cristian and L{\ae}gdsmand, Asbj{\o}rn {\O}rnemark and Ben Ltaief, Ltaief and Hoque, Ziaul and Roos, Andreas Hult and Jurkovičov{\´a}, Lucie and Hort, Ondřej and Finke, Ondřej and Albrecht, Martin and Nejdl, Jaroslav and Stienkemeier, Frank and Andreasson, Jakob and Klimešov{\´a}, Eva and Krikunova, Maria and Heidenreich, Andreas and Mudrich, Marcel}, title = {Long-lasting XUV activation of helium nanodroplets for avalanche ionization}, series = {New Journal of Physics}, volume = {25}, journal = {New Journal of Physics}, publisher = {Institute of Physics (IOP)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-17701}, year = {2023}, abstract = {We study the dynamics of avalanche ionization of pure helium nanodroplets activated by a weak extreme-ultraviolet (XUV) pulse and driven by an intense near-infrared (NIR) pulse. In addition to a transient enhancement of ignition of a nanoplasma at short delay times \${\sim}200\$ fs, long-term activation of the nanodroplets lasting up to a few nanoseconds is observed. Molecular dynamics simulations suggest that the short-term activation is caused by the injection of seed electrons into the droplets by XUV photoemission. Long-term activation appears due to electrons remaining loosely bound to photoions which form stable 'snowball' structures in the droplets. Thus, we show that XUV irradiation can induce long-lasting changes of the strong-field optical properties of nanoparticles, potentially opening new routes to controlling avalanche-ionization phenomena in nanostructures and condensed-phase systems.}, language = {en} } @article{SishodiaBenLtaiefScheeletal.2026, author = {Sishodia, Keshav and Ben Ltaief, Ltaief and Scheel, Niklas and F{\"o}ldes, Istv{\´a}n B. and Roos, Andreas Hult and Albrecht, Martin and Staněk, Maty{\´a}š and Jurkovičov{\´a}, Lucie and Hort, Ondrej and Nejdl, Jaroslav and Garc{\´i}a-Alfonso, Ernesto and Halberstadt, Nadine and Andreasson, Jakob and Klimešov{\´a}, Eva and Krikunova, Maria and Krishnan, Sivarama and Heidenreich, Andreas and Mudrich, Marcel}, title = {XUV fluorescence as a probe of interatomic coulombic decay of resonantly excited He nanodroplets}, series = {Scientific Reports}, volume = {16}, journal = {Scientific Reports}, number = {1}, publisher = {Springer Nature}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-21050}, year = {2026}, abstract = {Superfluid He nanodroplets resonantly excited by extreme ultraviolet (XUV) pulses can relax via interatomic coulombic decay (ICD), generally considered an ultrafast process. Here, we introduce a novel approach to probe the dynamics of ICD in He nanodroplets over timescales ranging from femtoseconds to nanoseconds. Our method relies on detecting XUV fluorescence emitted from the nanodroplets as they are driven into a nanoplasma by subsequent intense infrared pulses. Nanoplasma ignition is facilitated by tunnel ionization of XUV-excited He∗ atoms attached to the droplets; it thus serves as a sensitive probe of their relaxation dynamics. The observed nanosecond-scale decay is attributed to ICD between pairs of He∗ atoms undergoing roaming motion on the droplet surface, as supported by quantum-mechanical and classical model calculations.}, language = {en} }