Collective Autoionization in Multiply-Excited Systems: A novel ionization process observed in Helium Nanodroplets
Abstract
Free electron lasers (FELs) offer the unprecedented capability to study reaction dynamics and image the structure of complex systems. When multiple photons are absorbed in complex systems, a plasma-like state is formed where many atoms are ionized on a femtosecond timescale. If multiphoton absorption is resonantly-enhanced, the system becomes electronically-excited prior to plasma formation, with subsequent decay paths which have been scarcely investigated to date. Here, we show using helium nanodroplets as an example that these systems can decay by a new type of process, named collective autoionization. In addition, we show that this process is surprisingly efficient, leading to ion abundances much greater than that of direct single-photon ionization. This novel collective ionization process is expected to be important in many other complex systems, e.g. macromolecules and nanoparticles, exposed to high intensity radiation fields.
Keywords
Cite
@article{arxiv.1311.7514,
title = {Collective Autoionization in Multiply-Excited Systems: A novel ionization process observed in Helium Nanodroplets},
author = {A. C. LaForge and M. Drabbels and N. Brauer and M. Coreno and M. Devetta and M. Di Fraia and P. Finetti and C. Grazioli and R. Katzy and V. Lyamayev and T. Mazza and M. Mudrich and P. OKeeffe and Y. Ovcharenko and P. Piseri and O. Plekan and K. C. Prince and R. Richter and S. Stranges and C. Callegari and T. Moeller and F. Stienkemeier},
journal= {arXiv preprint arXiv:1311.7514},
year = {2020}
}