Knowledge Bank

Two anomalies, apparently inexplicable in terms of presently acceptable theories of liquid water, are noted when infrared spectra of liquid water and simple inorganic hydrates are compared. These anomalies are explained in terms of a Maxwellian distribution of random collisional interactions between water molecules, which when put in quantitative form reveal that (1) most molecules in the liquid are highly distorted by collisional perturbations, and (2) there is a broad distribution of distortion among the molecules in the liquid. When translated into vibrational dynamics, this leads to a continuous distribution of $\nu 1$ and $\nu 3$ modes of varying distorted molecules. It is shown that in its stretching motion, liquid water behaves dynamically as a continuum of OH bond oscillators of different frequencies, demonstrating both weak, but detectable, inter- and intramolecular vibrational interactions. A new interpretation of the infrared spectrum of liquid water is given in terms of this model, and other spectral evidence is offered in support of it.