Water-Mediated Excited State Proton Transfer of Pyranine-Acetate in Aqueous Solution: Vibrational Fingerprints from Ab Initio Molecular Dynamics.

ABSTRACT: In this work, we simulate the excited state proton transfer (ESPT) reaction involving the pyranine photoacid and an acetate molecule as proton acceptor, connected by a bridge water molecule. We employ ab initio molecular dynamics combined with an hybrid quantum/molecular mechanics (QM/MM) framework. Furthermore, a time-resolved vibrational analysis based on the wavelet-transform allows one to identify two low frequency vibrational modes that are fingerprints of the ESPT event: a ring wagging and ring breathing. Their composition suggests their key role in optimizing the structure of the proton donor-acceptor couple and promoting the ESPT event. We find that the choice of the QM/MM partition dramatically affects the photoinduced reactivity of the system. The QM subspace was gradually extend

SUBMITTER: Chiariello MG 

PROVIDER: S-EPMC8279639 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature