Renner-Teller nonadiabatic coupling terms: An ab-initio study of the HNH molecule

G. Halász, A. Vibók, R. Baer, M. Baer

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Abstract

In this Communication we present the first theoretical/numerical treatment of nonadiabatic coupling terms (NACT) that originate from the Renner-Teller (RT) model, namely, those that follow from the splitting of an electronic level of a linear molecule when it becomes bent. These two newly formed states are characterized by different symmetries and are designated as A and B. Our main findings: (1) The RT NACTs are quantized as long as they are calculated close enough to collinear configuration of the molecule (in this case HNH). Their value is τ=1 (the Jahn-Teller values in similar situations, are τ=12). (2) Calculation of RT NACTs at bent configurations (i.e., at a distance from the linear axis) yield decreased values, sometimes by more than 50%. This last finding implies that in strongly bent configurations the two-state Hilbert subspace (formed by the above mentioned A and B states) is affected by upper states, most likely via Jahn-Teller conical intersections. (3) This study has also important practical implications. The fact that the RT NACTs decrease in (strongly) bent situations implies that analyzing spectroscopic data employing only the two Π -states may not be sufficient in order to achieve the required accuracy.

Original languageEnglish
JournalThe Journal of Chemical Physics
Volume124
Issue number8
DOIs
Publication statusPublished - 2006

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Molecules
configurations
molecules
electronic levels
intersections
Communication
communication
symmetry

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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Renner-Teller nonadiabatic coupling terms : An ab-initio study of the HNH molecule. / Halász, G.; Vibók, A.; Baer, R.; Baer, M.

In: The Journal of Chemical Physics, Vol. 124, No. 8, 2006.

Research output: Contribution to journalArticle

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