Near-infrared photoabsorption by C60 dianions in a storage ring
| Autor: | Shigeo Tomita, Umesh Kadhane, Olof Echt, Preben Hvelplund, B. Concina, Jimmy Rangama, M. B. Suhr Kirketerp, Henning Zettergren, Sophie E. Canton, Klavs Hansen, E. Bonderup, Bo Liu, J. S. Forster, Subhasis Panja, A. E. K. Sundén, Jens Ulrik Andersen, S. Brøndsted Nielsen, Kristian Støchkel |
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| Rok vydání: | 2009 |
| Předmět: |
Jahn-Teller
Near Infrared Photon absorptions Lowest unoccupied molecular orbital Photoabsorption Vapor cells Jahn–Teller effect General Physics and Astronomy Aromatic hydrocarbons Laser induced Absorption band Infrared spectroscopy HOMO/LUMO Chemistry Singlet ground state Dianions Molecular orbitals Wind tunnels Atomic physics Ground state Monoanions Infrared devices Electronic structure Electronic levels Absorption spectroscopy Electrons Electron spin resonance measurements Spin dynamics Molecular electronic transition Electron transfer Gasphase Jahn-Teller couplings Potential energy Internal conversions Electron spin resonance spectroscopy Gas absorption Electronic transition Light absorption Physical and Theoretical Chemistry Quadrupole deformations Electron detachments Coulomb barrier Time dependence Near-infrared absorption Cell membranes Dianion |
| Zdroj: | Journal of Chemical Physics Kadhane, U, Andersen, J U, Bonderup, E, Concina, B J M F, Hvelplund, P, Kirketerp, M-B S, Liu, B, Nielsen, S B, Panja, S, Rangama, J, Støchkel, K, Tomita, S, Zettergren, H, Hansen, K, Sundén, A E K, Canton, S E, Echt, O & Forster, J S 2009, ' Near-infrared photoabsorption by C 60 dianions in a storage ring ', Journal of Chemical Physics, vol. 131, no. 014301 . https://doi.org/10.1063/1.3149775 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.3149775 |
| Popis: | We present a detailed study of the electronic structure and the stability of C(60) dianions in the gas phase. Monoanions were extracted from a plasma source and converted to dianions by electron transfer in a Na vapor cell. The dianions were then stored in an electrostatic ring, and their near-infrared absorption spectrum was measured by observation of laser induced electron detachment. From the time dependence of the detachment after photon absorption, we conclude that the reaction has contributions from both direct electron tunneling to the continuum and vibrationally assisted tunneling after internal conversion. This implies that the height of the Coulomb barrier confining the attached electrons is at least approximately 1.5 eV. For C(60)(2-) ions in solution electron spin resonance measurements have indicated a singlet ground state, and from the similarity of the absorption spectra we conclude that also the ground state of isolated C(60)(2-) ions is singlet. The observed spectrum corresponds to an electronic transition from a t(1u) lowest unoccupied molecular orbital (LUMO) of C(60) to the t(1g) LUMO+1 level. The electronic levels of the dianion are split due to Jahn-Teller coupling to quadrupole deformations of the molecule, and a main absorption band at 10,723 cm(-1) corresponds to a transition between the Jahn-Teller ground states. Also transitions from pseudorotational states with 200 cm(-1) and (probably) 420 cm(-1) excitation are observed. We argue that a very broad absorption band from about 11,500 cm(-1) to 13,500 cm(-1) consists of transitions to so-called cone states, which are Jahn-Teller states on a higher potential-energy surface, stabilized by a pseudorotational angular momentum barrier. A previously observed, high-lying absorption band for C(60)(-) may also be a transition to a cone state. |
| Databáze: | OpenAIRE |
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