To further demonstrate the applicability of WS+MD and SWS+MD for the calculation of vibrational properties and to compare the performance of MD with harmonic and VPT2 vibrational models, we have performed three additional sets of calculations for different molecular systems. We have chosen benzene (C 6 H 6 ), protonated methane cation (CH + 5 ) and protonated serine octamer (Ser 8 H + , (C 3 H 7 NO 3 ) 8 H + , see Fig. ). For all of them there have been published high quality experimental and theoretical data. Benzene is an example of a simple and semi-rigid system, for which are available experimental rotational constants with respective theoretical anharmonic corrections , vibrational and photoelectron (PE) spectra . CH + 5 was taken as a system with large amplitude motions (LAMs) requiring treatment beyond the localized vibrational harmonic and VPT2 approximations. Ser 8 H + is used to demonstrate the increasing computational expenses of the VPT2 approach compared to MD.