Large ion clusters H N+ of Rydberg Matter: Stacks of planar clusters H 7

Abstract

Hydrogen and alkali atoms can form low-density metallic phases, in their most well-ordered form called Rydberg Matter (RM). RM consists mainly of small six-fold symmetric planar clusters in point group D 6h as shown by rotational spectroscopy. In their “sleeping top” (dark) state they can form stacks of clusters, as recently observed by 39K nuclear spin-flip transitions. Stacks of clusters H 7 are now directly observed by TOF-MS, using a laser intensity of <10 15 W cm −2. The TOF-MS resolution is high and the excitation level is found to be n B = 1. The Coulomb explosion process giving the ions observed involves rupture of an H 7 cluster in the stack and probably also addition of a proton to a cluster stack. Further mechanisms are discussed. RM clusters of the stack type can be larger than the previously observed limit for planar RM clusters of N = 91. That no N = 7 clusters but only larger planar RM clusters were detected in previous rotational spectroscopy studies is now suggested to be due to formation of cluster stacks.