Abstract
C-60(2-) and C-70(2-) dianions have been produced by electrospray of the monoanions and subsequent electron pickup in a Na vapor cell. The dianions were stored in an electrostatic ring and their decay by electron emission was measured up to 1 s after injection. While C-70(2-) ions are stable on this time scale, except for a small fraction of the ions which have been excited by gas collisions, most of the C-60(2-) ions decay on a millisecond time scale, with a lifetime depending strongly on their internal temperature. The results can be modeled as decay by electron tunneling through a Coulomb barrier, mainly from thermally populated triplet states about 120 meV above a singlet ground state. At times longer than about 100 ms, the absorption of blackbody radiation plays an important role for the decay of initially cold ions. The tunneling rates obtained from the modeling, combined with WKB estimates of the barrier penetration, give a ground-state energy 200 +/- 30 meV above the energy of the monoanion plus a free electron and a ground-state lifetime of the order of 20 s. (c) 2006 American Institute of Physics.
Department
Physics
Publication Date
1-10-2006
Journal Title
Journal of Chemical Physics
Publisher
AMERICAN INSTITUTE OF PHYSICS
Digital Object Identifier (DOI)
10.1063/1.2155435
Document Type
Article
Recommended Citation
The following article appeared in J. Chem. Phys. 124, 024310 (2006); doi: 10.1063/1.2155435 and may be found at http://dx.doi.org/10.1063/1.2155435.
Rights
© 2006 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.