Anticipating Acene-Based Chromophore Spectra with Molecular Orbital Arguments
| Autor: | Matthew Y. Sfeir, Luis M. Campos, Timothy J. H. Hele, Nandini Ananth, Eric G. Fuemmeler, Elango Kumarasamy, Samuel N. Sanders |
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| Rok vydání: | 2019 |
| Předmět: |
Chemical Physics (physics.chem-ph)
010304 chemical physics FOS: Physical sciences Electronic structure Chromophore 010402 general chemistry 01 natural sciences Spectral line 0104 chemical sciences 3. Good health Pentacene chemistry.chemical_compound Monomer Tetracene chemistry Chemical physics Physics - Chemical Physics 0103 physical sciences Molecular orbital Physical and Theoretical Chemistry Acene |
| Zdroj: | The Journal of Physical Chemistry A. 123:2527-2536 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/acs.jpca.8b12222 |
| Popis: | Recent synthetic studies on the organic molecules tetracene and pentacene have found certain dimers and oligomers to exhibit an intense absorption in the visible region of the spectrum which is not present in the monomer or many previously-studied dimers. In this article we combine experimental synthesis with electronic structure theory and spectral computation to show that this absorption arises from an otherwise dark charge-transfer excitation 'borrowing intensity' from an intense UV excitation. Further, by characterizing the role of relevant monomer molecular orbitals, we arrive at a design principle that allows us to predict the presence or absence of an additional absorption based on the bonding geometry of the dimer. We find this rule correctly explains the spectra of a wide range of acene derivatives and solves an unexplained structure-spectrum phenomenon first observed seventy years ago. These results pave the way for the design of highly absorbent chromophores with applications ranging from photovoltaics to liquid crystals. 29 pages, 63 pages with SI, 5 figures |
| Databáze: | OpenAIRE |
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