Physical Sciences and Mathematics Commons^™

Formation Of Even-Numbered Hydrogen Cluster Cations In Ultracold Helium Droplets, S. Jaksch, A. Mauracher, A. Bacher, S. Denifl, F. Ferreira De Silva, H. Schoebel, Olof E. Echt, T. D. Maerk, M. Probst, D. K. Bohme, P. Scheier

Physics & Astronomy

Neutral hydrogen clusters are grown in ultracold helium nanodroplets by successive pickup of hydrogen molecules. Even-numbered hydrogen cluster cations are observed upon electron-impact ionization with and without attached helium atoms and in addition to the familiar odd-numbered H(n)(+). The helium matrix affects the fragmentation dynamics that usually lead to the formation of overwhelmingly odd-numbered H(n)(+). The use of high-resolution mass spectrometry allows the unambiguous identification of even-numbered H(n)(+) up to n congruent to 120 by their mass excess that distinguishes them from He(n)(+), mixed He(m)H(n)(+), and background ions. The large range in size of these hydrogen cluster ions is unprecedented, …