In addition to aforementioned popular methods based on static calculations, there is another category of methods that is based on dynamic simulations and employs time au-tocorrelation functions to obtain vibrational spectra. Among them, a widely-used method is classical molecular dynamics (MD) , which treats nuclei as classical particles and let them evolve classically on PESs following Newton's laws of motion. Within the classical MD framework, ab initio MD (AIMD) is generally more accurate than force-field-based MD because the PESs used in AIMD are obtained through ab initio electronic structure calculations, such as DFT. However, classical MD can only take into account limited amount of anharmonicty through dynamic simultations on PESs at a finite temperature and often needs empirical scaling factors for highly anharmonic systems. An improved way to incorporate more anharmonicity in MD simulations is through quasi-or semi-classical methods .