Communication: Ultrafast time-resolved ion photofragmentation spectroscopy of photoionization-induced proton transfer in phenol-ammonia complex.
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.
Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan.
Ching-Chi
CC
Shen
Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan.
Tsung-Ting
TT
Tsai
Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan.
Jr-Wei
JW
Ho
Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan.
Yi-Wei
YW
Chen
Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan.
Po-Yuan
PY
Cheng
D000641:Ammonia / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D055668:Photochemical Processes; D011522:Protons; D011789:Quantum Theory; D013057:Spectrum Analysis; D013997:Time Factors
D010636:Phenols; D011522:Protons; D000641:Ammonia