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Updated: Jun 19, 2026

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Electronic absorption spectrum of a nonlinear carbon chain: trans-C6H4+
Mitsunori Araki1, Tomasz Motylewski, Przemyslaw Kolek
1Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
Abstract:
The 2Bg-X2Au transition of a nonlinear carbon chain trans-C6H4+, and trans-C6D4+, has been observed in the gas phase. The spectra were detected in the 580 nm region by direct absorption with a cavity ringdown technique through a supersonic planar discharge. Though the rotational structure is not resolved, the band profiles were analyzed using a "total spectral fitting" procedure using ground-state constants calculated by the CASSCF and CASPT2 methods. The molecular constants in the upper state could thus be determined.
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