Experimental observation of a very high second electron affinity for ZrF{sub 6} from photodetachment of gaseous ZrF{sub 6}{sup 2{minus}} doubly charged anions
The authors report a photodetachment photoelectron spectroscopy study of a doubly charged anion, ZrF{sub 6}{sup 2{minus}}, in the gas phase at two photo energies: 6.424 (193 nm) and 7.865 (157 nm) eV. The adiabatic detachment energy, i.e., the second electron affinity of ZrF{sub 6}, was measured to be extremely high, 2.9(0.2) eV. The vertical detachment energy (VDE) was measured to be 3.4(0.1) eV. Two excited states were also observed for the ZrF{sub 6}{sup {minus}} singly charged anion with VDEs at 4.0 and 4.6 eV, respectively. The repulsive Coulomb barrier, and hence the intramolecular Coulomb repulsion in ZrF{sub 6}{sup 2{minus}}, was estimated from the photon-energy-dependent spectra to be {approximately}2.4 eV. The ZrF{sub 6}{sup 2{minus}} dianion was observed to be metastable with a half-life of {approximately}4 s under the experimental conditions, confirming theoretical predictions that ZrF{sub 6}{sup 2{minus}} is thermodynamically unstable against loss of an F{sup {minus}}, despite its extremely high electronic stability. The authors also performed experiment for the singly charged ZrF{sub 5}{sup {minus}}, but could not observe photodetachment even at 157 nm, the highest photon energy available to us. Thus, the estimated electron affinity of ZrF{sub 5} is larger than 7.8 eV, the highest electron affinity yet confirmed experimentally.
- Research Organization:
- Washington State Univ., Richland, WA (US)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 20075896
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 104, Issue 19; Other Information: PBD: 18 May 2000; ISSN 1089-5639
- Country of Publication:
- United States
- Language:
- English
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