Autocorrelation Functions of the Translational and Rotational Velocities of Water

The autocorrelation functions of the translational and rotational velocities of rigid water molecules with different potentials of interatomic interaction are calculated by means of molecular dynamics. Spectral distributions are constructed for all functions. The translational spectra of each model have maxima at characteristic frequencies of 46 and 260 cm −1 ; rotational spectra, at 533 and 900 cm −1 . However, the weak correlation between translational and rotational motions results in characteristic translational frequencies in rotational spectra as well.