Large ion clusters HN+ of Rydberg Matter: Stacks of planar clusters H7

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 D6h 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 H7 are now directly observed by TOF-MS, using a laser intensity of <1015 W cm−2. The TOF-MS resolution is high and the excitation level is found to be nB = 1. The Coulomb explosion process giving the ions observed involves rupture of an H7 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.

Figure optionsDownload high-quality image (151 K)Download as PowerPoint slideResearch highlights▶ Clusters H7 of the lowest state of condensed atomic hydrogen form H(1) are identified by MS. ▶ Clusters H7 of this type are planar and form stacks with up to more than ten clusters in each stack. ▶ A common ion fragment contains three clusters H7. ▶ The H7 cluster stacks are less sensitive to the applied electric field than other H(1) cluster forms.