| Autor: |
Scott Hopkins, W., Marta, Rick A., Steinmetz, Vincent, McMahon, Terry B. |
| Zdroj: |
Physical Chemistry Chemical Physics (PCCP); 11/21/2015, Vol. 17 Issue 43, p28548-28555, 8p |
| Abstrakt: |
A combination of infrared multiple photon dissociation (IRMPD) spectroscopy and density functional theory calculations have been employed to study the structures and mode-specific dissociation pathways of the proton-bound dimer of 3-trifluoromethylphenylalanine (3-CF3-Phe) and trimethylamine (TMA). Three structural motifs are identified: canonical (charge-solvated), zwitterionic (charge-separated), and TMA-bridged. In the 1000–1350 cm−1 region, similar spectra are observed in the TMA·H+ and 3-CF3-Phe·H+ product channels. At wavenumbers above 1350 cm−1, infrared excitation of charge-solvated structures leads exclusively to production of protonated TMA, while excitation of zwitterionic or TMA-bridged structures results exclusively in production of protonated 3-CF3-Phe. The cluster potential energy landscape is topologically mapped and mechanisms for isomerization and mode-selective dissociation are proposed. In particular, cluster transparency as a result of IR-induced isomerization is implicated in deactivation of some IRMPD channels. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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