Vibrational excitation and energy redistribution after ultrafast internal conversion in 4-nitroaniline
| Autor: | Wolfgang Werncke, Matteo Rini, Jens Dreyer, Klaus-Werner Brzezinka, Thomas Elsaesser, V. Kozich, A. Kummrow |
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| Rok vydání: | 2002 |
| Předmět: |
education.field_of_study
Chemistry Overtone Population Analytical chemistry General Physics and Astronomy Overtone band Molecular physics Hot band Photoexcitation symbols.namesake Picosecond symbols Physics::Chemical Physics Physical and Theoretical Chemistry education Raman spectroscopy Raman scattering |
| Zdroj: | The Journal of Chemical Physics. 117:719-726 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.1482698 |
| Popis: | Nonequilibrium vibrational excitations of para-nitroaniline (PNA, 4-nitroaniline) occurring after internal conversion from the photoexcited charge transfer state are studied by picosecond anti-Stokes Raman scattering. Vibrational excess populations with distinctly different picosecond rise and decay times are found for a number of modes with frequencies between 860 and 1510 cm−1, including the overtone of a non-Raman active mode. A nonthermal distribution of vibrational populations exists up to about 6 ps after photoexcitation. The time-resolved experiments are complemented by steady-state infrared and Raman measurements as well as calculations based on density functional theory, providing a detailed analysis of the steady-state vibrational spectra of PNA and two of its isotopomers. A weakly Raman active vibration at about 1510 cm−1 displays the fastest rise time and a pronounced excess population and—thus—represents the main accepting mode. We suggest that an out-of-plane mode giving rise to the overtone... |
| Databáze: | OpenAIRE |
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