Abstract

Using molecular dynamics simulations, we investigate the fluctuations of the hydrogen-bond network in liquid water and its relation to vibrational spectroscopy. We show that the high-frequency shoulder, which is most evidently found in Raman spectra of the OH stretch vibration of isotope diluted water, is (at least to a certain extent) related to a three-fold hydrogen-bonded ring. This suggests that it is not always sufficient to classify individual water molecules when studying some aspects of hydrogen-bond dynamics, rather, one should consider the topology of the local structure around a given water molecule.