Fall-back time for photo-ionized Cs atoms attached to superfluid 4He nanodroplets François Coppens, Johannes von Vangerow, Antonio Leal, Manuel Barranco, Nadine Halberstadt, Marcel Mudrich, Martí Pi and Frank Stienkemeier Eur. Phys. J. D, 73 5 (2019) 94 Published online: 07 May 2019 DOI: 10.1140/epjd/e2019-90692-0