LIQUID WATER - DENSITY-OF-STATES SPECTRA OF SOLVATED WATER-MOLECULES WITH SPECIFIC COORDINATION

Using the trajectories obtained in molecular dynamics simulations of l iquid water at T = 305 K, the density of states for the hydrogen atoms of ''solvated water molecules'', specifically those which are hydroge n bonded to either 2, or 3, or 4, or 5 water molecules, have been comp uted. Our analysis reveals that liquid water can be modelled as a dyna mical mixture of solvated water molecules with different coordination numbers (from two to five). The corresponding spectra reveal major var iations at all frequencies. In particular, the spectra of the 3-hydrog en-bonded water molecules, when compared with the 4-hydrogen-bonded wa ter molecules, are red-shifted by almost-equal-to 120 cm-1 in the libr ational region, by almost-equal-to 3 5 cm-1 in the bending region, and blue-shifted by almost-equal-to 35 and almost-equal-to 75 cm-1 for th e symmetric and asymmetric stretching, respectively.