Caught in the act: Excited-state Proton Transfer to the solvent followed in real time by non-linear THz spectroscopy

摘要: We have investigated the solvent response after photoexcitation using Optical Pump THz Probe (OPTP) spectroscopy with sub-ps time resolution in combination quantum-chemical modeling. Excited State Proton Transfer (ESPT) is found to be facilitated by excitation of an intermolecular stretch (H pyranine -O water ) triggered instantaneous (< 100 fs) redistribution charge density. Initiation proton transfer observed on a scale 0.4 ps, i.e. much shorter than anticipated before. Our results demonstrate exceptional sensitivity OPTP, which enables us follow motion into hydrogen bond network exploring transport transient configurations real time.