Limitations of Generic Chromophore Concept for Femtosecond Vibrational Coherences
| Autor: | Tomasz Skóra, Piotr Petelenz, Marcin Andrzejak |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Physics
Wave packet Chromophore Molecular physics Spectral line Surfaces Coatings and Films Electronic Optical and Magnetic Materials Pentacene chemistry.chemical_compound General Energy chemistry Ab initio quantum chemistry methods Normal mode Femtosecond Physics::Atomic and Molecular Clusters Singlet state Physics::Chemical Physics Physical and Theoretical Chemistry |
| Zdroj: | The Journal of Physical Chemistry C. 124:3529-3535 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/acs.jpcc.9b11772 |
| Popis: | The spectrum of vibrational coherences modulating transient triplet–triplet absorption of bis-triisopropylsilylethynylpentacene that propagate in the course of the fission process from the singlet state of this molecule to the triplet manifold has been lately reproduced by ab initio calculations. This has led to the conclusion that, contrary to a recent hypothesis, spontaneous generation of coherent vibrational wave packets is not a constitutive feature of singlet exciton fission. Here we demonstrate by calculations that the corresponding spectrum of unsubstituted pentacene is significantly different, so that the two systems cannot be viewed as different models of the same generic chromophore. This shows that femtosecond pump–probe spectra of vibrational coherences are sensitive to subtle features of molecular structure, which we identify here, thereby rationalizing the registered spectral differences. The crucial factor is the substituent-induced coupling between some pentacene normal modes that in other... |
| Databáze: | OpenAIRE |
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