The O-H stretching peak (ν OH ) is located at approximately 3800 cm -1 in both QM and ML simulations (in vacuo), aligning well with previous reports on the accuracy of the ANI-2x model in capturing vibrational modes of organic molecules. The experimental gas-phase νOH value for phenol is reported around 3656 cm -1 , 87 meaning our QM and ML simulations overestimate its value by ∼150 cm -1 . The QM prediction of the phenol O-H stretching at the B3LYP/6-31G* level has been reported to be ∼100 cm -1 86 lower than the experimental value. This highlights the large dependence of this magnitude on the level of theory, and the ability of in vacuo ML MD simulations to reproduce the analogue QM level accurately.