Schweke, D. and Baumgarten, H. and Haas, Yehuda and Rettig, W. and Dick, Bernhard (2005) Charge-transfer-type fluorescence of 4-(1H-pyrrol-1-yl)benzonitrile (PBN) and N-phenylpyrrole (PP) in cryogenic matrixes: Evidence for direct excitation of the CT band. JOURNAL OF PHYSICAL CHEMISTRY A, 109 (4). pp. 576-585. ISSN 1089-5639,
Full text not available from this repository. (Request a copy)Abstract
The fluorescence spectrum of PBN in a neat argon matrix is excitation-wavelength-dependent: at short excitation wavelengths, it consists of dual emission assigned to a charge-transfer (CT) state and a much weaker band assigned to the locally excited (LE) state. The CT emission is broad and almost completely devoid of vibrational structure, whereas the LE band is characterized by vibrationally resolved emission. At long excitation wavelengths, only CT emission is observed, indicating that the CT state is populated directly by light absorption and not via the LE state. Comparison with jet-cooled spectra of the bare molecule allows the unambiguous assignment of the LE spectrum and the location of the 0,0 band. The matrix LE emission spectrum is blue-shifted with respect to that of the gas phase, showing that the dipole moment of the LE state is smaller than that of the ground state. The fluorescence spectrum of PBN in an argon matrix does not change appreciably when acetonitrile (AN) is added to the matrix, in contrast to the case of N-phenylpyrrol (PP) (Schweke, D.; Haas, Y. J. Phys. Chem. A 2003, 107, 9554), for which addition of AN results in the appearance of two well separated emission bands. The different photophysical behaviors of PP and PBN in an argon matrix (and in supersonic jets) are analyzed by a simple model that considers the restriction of large-amplitude motions in the matrix. The implications of these low-temperature studies for understanding the properties of these systems in liquid solution are discussed.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | MOLECULAR-DYNAMICS SIMULATIONS; MONTE-CARLO SIMULATIONS; TRANSFER STATES; EXCITED-STATE; LIQUID ACETONITRILE; DUAL FLUORESCENCE; PYRROLOBENZONITRILE; CONFORMATION; SPECTROSCOPY; MINIMIZATION; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry III - Physical Chemistry (Molecular Spectroscopy and Photochemistry) > Prof. Dr. Bernhard Dick |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 28 May 2021 09:54 |
| Last Modified: | 28 May 2021 09:54 |
| URI: | https://pred.uni-regensburg.de/id/eprint/36490 |
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