To understand the vibrational dynamics of MP2 water, we calculate the density of states (VDOS) from the Fourier Transform of the velocity-velocity auto-correlation function at different temperatures. As shown in Fig. , classical MD simulations overestimate the OH-stretch mode and bend mode by around 300 cm -1 and 40 -1 compared to experiment at room temperature (with the experimental OH stretch at 3380 cm). In quantum simulations, the O-H stretching frequency is red- shifted from 3685 cm -1 to 3524 cm -1 (from TRPMD) and 3442 cm -1 (PACMD), with the latter agreeing better with the experiment. NQEs also contribute to the improvement of the bending mode (experimentally 1637 cm -1 in the IR measurement) from 1693 (classical) to 1624 (quantum). While the agreement of MP2 calculations with experiments is very good, that of revPBE0-D3 water is somewhat better, particularly for the O-H stretching peak . The PACMD results for the librational and bending modes in water are reasonably good across the range of temperatures studied, but the agreement between the experimental and PACMD O-H stretching modes improves as the temperature is decreased, with quantum results at 240 K giving the best agreement with experiments. IV. CONCLUSIONS