Counterintuitive effects of the electron correlation in the first-excited state of the hydrogen moleculeJian Wang1, 2, J. M. Mercero1, I. Silanes1 and J. M. Ugalde1
1 Kimika Fakultatea, Euskal Herriko Unibertsitatea and Donostia International Physics Center - P.K. 1072, 20080 Donostia, Euskadi, Spain
2 School of Science, Huzhou University - 313000 Huzhou, PRC
received 16 August 2006; accepted in final form 29 September 2006
published online 20 October 2006
The first-excited state of the hydrogen molecule has a potential energy curve with two minima, labeled as E and F, respectively. In the transition from the E minimum to the F minimum, the mean interelectronic distance decreases as the nuclear distance increases, which is in contrast to the behavior of the ground state. Previously the F minimum has been identified as arising from the configuration. Our results suggest that it rather arises from the combination of the and configurations, which leads to the formation of an instant ionic pair, , with the unshared electron pair resonating between the two hydrogen nuclei.
31.25.Jf - Electron correlation calculations for atoms and ions: excited states.
31.10.+z - Theory of electronic structure, electronic transitions, and chemical binding.
31.15.Ar - Ab initio calculations.
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