Stability and Cooling of the C 2− 7  Dianion

• Published in: Physical review letters Vol. 131; no. 11
• Main Authors: Najeeb, P. K., Stockett, Mark H., Anderson, Emma K., Kristiansson, Moa, Reinhed, Peter, Simonsson, Ansgar, Rosén, Stefan, Thomas, Richard D., Chartkunchand, K. C., Gnaser, H., Golser, R., Hanstorp, D., Larson, Åsa, Cederquist, Henrik, Schmidt, Henning T., Zettergren, Henning
• Format: Journal Article
• Language: English
• Published: 2023
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.131.113003

We have studied the stability of the smallest long-lived all carbon molecular dianion (<img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?C_%7B7%7D%5E%7B2-%7D" data-classname="equation" />) in new time domains and with a single ion at a time using a cryogenic electrostatic ion-beam storage ring. We observe spontaneous electron emission from internally excited dianions on millisecond timescales and monitor the survival of single colder <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?C_%7B7%7D%5E%7B2-%7D" data-classname="equation" /> molecules on much longer timescales. We find that their intrinsic lifetime exceeds several minutes—6 orders of magnitude longer than established from earlier experiments on <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?C_%7B7%7D%5E%7B2-%7D" data-classname="equation" />. This is consistent with our calculations of vertical electron detachment energies predicting one inherently stable isomer and one isomer which is stable or effectively stable behind a large Coulomb barrier for <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?C_%7B7%7D%5E%7B2-%7D" data-classname="equation" data-title="" />→<img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?C_%7B7%7D%5E%7B-%7D" data-classname="equation" data-title="" />+e − separation.