Communication: Ultrafast time-resolved ion photofragmentation spectroscopy of photoionization-induced proton transfer in phenol-ammonia complex
| Autor: | Po-Yuan Cheng, Jr-Wei Ho, Ching-Chi Shen, Yi-Wei Chen, Tsung-Ting Tsai |
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| Rok vydání: | 2014 |
| Předmět: |
Time Factors
Proton Chemistry Spectrum Analysis General Physics and Astronomy Photoionization Photochemical Processes Photochemistry Spectral line Ion Phenols Fragmentation (mass spectrometry) Ammonia Ionization Femtosecond Quantum Theory Protons Physical and Theoretical Chemistry Atomic physics Spectroscopy |
| Zdroj: | The Journal of Chemical Physics. 141:171103 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.4901329 |
| Popis: | Photoionization-induced proton transfer (PT) in phenol-ammonia (PhOH-NH3) complex has been studied using ultrafast time-resolved ion photofragmentation spectroscopy. Neutral PhOH-NH3 complexes prepared in a free jet are photoionized by femtosecond [1+1] resonance-enhanced multiphoton ionization via the S1 state, and the subsequent dynamics occurring in the cations is probed by delayed pulses that result in ion fragmentation. The observed temporal evolutions of the photofragmentation spectra are consistent with an intracomplex PT reaction. The experiments revealed that PT in [PhOH-NH3](+) cation proceeds in two distinct steps: an initial impulsive wave-packet motion in ~70 fs followed by a slower relaxation of about 1 ps that stabilizes the system into the final PT configuration. These results indicate that for a barrierless PT system, even though the initial PT motions are impulsive and ultrafast, the reaction may take a much longer time scale to complete. |
| Databáze: | OpenAIRE |
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