In contrast, DFT harmonic analysis overestimates the frequency by about 200 cm -1 and AIMD makes the overestimation slightly worse. Despite the great success of CNEO-MD in reproducing the main bands of the experimental IR spectra, we point out a small feature that seems absent in CNEO-MD: a diffuse feature that lies about 380 cm -1 above the dominant peak in both experimental spectra. 12,89 With several high level methods, this feature has been attributed to various overtones and combination bands, especially the combination band involving the O-O stretch mode. 12,90 AIMD seems to have fortuitously captured some diffuse feature at around 3200 cm -1 , but far from the experimental reference, and for CNEO-MD, this feature is not observed in the spectrum. The reason is that although CNEO-MD accounts for quantum nuclear delocalization effects, it is still based on classical MD, and it is known in the past that the accurate description of overtones, combination bands, and Fermi resonances have been particularly challenging for classical MD. Therefore, these features should not be anticipated from either AIMD or CNEO-MD, although some Fermi resonance has been fortunately captured by CNEO-MD in the past. The frequencies of free O-H stretches can be accurately described with both CNEO harmonic analysis and CNEO-MD, which is consistent with the results from all previous investigations.