The effect of substituents on the vibronic structure of the electronic spectra of alpha,omega-dithienylpolyenes: A computational study

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DOIResolve DOI: http://doi.org/10.1063/1.1381576
AuthorSearch for: ; Search for:
TypeArticle
Journal titleThe Journal Of Chemical Physics
Volume115
Issue3
Pages12981311; # of pages: 14
Subjectab initio calculations; excited states; ground states; molecular force constants; polymers; spectra; vibronic states
AbstractWe present a quantum chemical investigation of the vibronic structure in the electronic spectra of three alpha,omega-dithienylpolyenes. Equilibrium structures and vibrational force fields of ground and excited electronic states are computed at semiempirical and ab initio levels of theory. The molecular parameters are employed to calculate displacement parameters for totally symmetric modes which are then used to model the vibronic structure of emission and absorption spectra. The observed spectral features are well reproduced by the computed spectra and two characteristic frequency regions are identified for the emission spectra. The first, above 1500 cm–1, is due to the C[Double Bond]C stretching activity typical of trans polyenes. In addition, the strong activity in emission around 1430 cm–1 is rationalized by considering that the two etherocyclic rings add, to the central polyenic chain, a conjugated carbon skeleton with cis linkages. In analogy with the oligomers of thiophene, the cis linkages, along with vibronic coupling, are responsible for the remarkable activity observed in emission in this frequency region.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada; NRC Steacie Institute for Molecular Sciences
Peer reviewedYes
NPARC number12327384
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Record identifier59d27fd4-91ae-48d5-89a2-fe327f420927
Record created2009-09-10
Record modified2017-03-23
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