State-resolved infrared spectrum of the protonated water dimer: revisiting the characteristic proton transfer doublet peak.

ABSTRACT: The infrared (IR) spectra of protonated water clusters encode precise information on the dynamics and structure of the hydrated proton. However, the strong anharmonic coupling and quantum effects of these elusive species remain puzzling up to the present day. Here, we report unequivocal evidence that the interplay between the proton transfer and the water wagging motions in the protonated water dimer (Zundel ion) giving rise to the characteristic doublet peak is both more complex and more sensitive to subtle energetic changes than previously thought. In particular, hitherto overlooked low-intensity satellite peaks in the experimental spectrum are now unveiled and mechanistically assigned. Our findings rely on the comparison of IR spectra obtained using two highly accurate potential energy

SUBMITTER: Larsson HR 

PROVIDER: S-EPMC9517273 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature