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dc.contributor.authorGieseking, Rebecca L.
dc.contributor.authorRavva, Mahesh Kumar
dc.contributor.authorCoropceanu, Veaceslav
dc.contributor.authorBredas, Jean-Luc
dc.date.accessioned2016-05-04T14:01:40Z
dc.date.available2016-05-04T14:01:40Z
dc.date.issued2016-05-04
dc.identifier.citationBenchmarking Density Functional Theory Approaches for the Description of Symmetry-Breaking in Long Polymethine Dyes 2016 The Journal of Physical Chemistry C
dc.identifier.issn1932-7447
dc.identifier.issn1932-7455
dc.identifier.doi10.1021/acs.jpcc.6b02100
dc.identifier.urihttp://hdl.handle.net/10754/608228
dc.description.abstractLong polymethines are well-known experimentally to symmetry-break, which dramatically modifies their linear and nonlinear optical properties. Computational modeling could be very useful to provide insight into the symmetry-breaking process, which is not readily available experimentally; however, accurately predicting the crossover point from symmetric to symmetry-broken structures has proven challenging. Here, we benchmark the accuracy of several DFT approaches relative to CCSD(T) geometries. In particular, we compare analogous hybrid and long-range corrected (LRC) functionals to clearly show the influence of the functional exchange term. Although both hybrid and LRC functionals can be tuned to reproduce the CCSD(T) geometries, the LRC functionals are better performing at reproducing the geometry evolution with chain length and provide a finite upper limit for the gas-phase crossover point; these methods also provide good agreement with the experimental crossover points for more complex polymethines in polar solvents. Using an approach based on LRC functionals, a reduction in the crossover length is found with increasing medium dielectric constant, which is related to localization of the excess charge on the end groups. Symmetry-breaking is associated with the appearance of an imaginary frequency of b2 symmetry involving a large change in the degree of bond-length alternation. Examination of the IR spectra show that short, isolated streptocyanines have a mode at ~1200 cm-1 involving a large change in bond-length alternation; as the polymethine length or the medium dielectric increases, the frequency of this mode decreases before becoming imaginary at the crossover point.
dc.description.sponsorshipThis work was primarily supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health under Award Number R21NS084353. We acknowledge stimulating discussions with Drs. T. Körzdörfer, S.R. Marder, and J.W. Perry.
dc.language.isoen
dc.publisherAmerican Chemical Society (ACS)
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/acs.jpcc.6b02100
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.6b02100.
dc.titleBenchmarking Density Functional Theory Approaches for the Description of Symmetry-Breaking in Long Polymethine Dyes
dc.typeArticle
dc.contributor.departmentKAUST Solar Center (KSC)
dc.contributor.departmentLaboratory for Computational and Theoretical Chemistry of Advanced Materials
dc.contributor.departmentMaterial Science and Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalThe Journal of Physical Chemistry C
dc.eprint.versionPost-print
dc.contributor.institutionSchool of Chemistry and Biochemistry and Center for Organic Materials for All-Optical Switching Georgia Institute of Technology, Atlanta, Georgia 30332-0400
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)
kaust.personRavva, Mahesh Kumar
kaust.personBredas, Jean-Luc
refterms.dateFOA2017-04-25T00:00:00Z
dc.date.published-online2016-05-04
dc.date.published-print2016-05-12


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