Measurements of the lifetimes of electron bubbles in large size selected He-4(N)- droplets

The lifetimes of electron bubbles in large size selected He-4(N)- droplets have been measured in a molecular beam experiment to lie between 2 . 10(-3) and 0.2 s in droplets with sizes between N approximate to 10(5) and 10(7) atoms, respectively. The dependence of the lifetimes on the electric fields used to size select the droplets, on the energies of the incident electron s, and on the infrared radiation emitted from the apparatus walls were inve stigated and taken into account. The experimental lifetimes are many orders of magnitude smaller than predicted by earlier theories but consistent wit h a recent theory published by the authors in Phys. Rev. Lett. 81, 3892 (19 98. (C) 1999 American Institute of Physics. [S0021-9606(99)01016-8].