The first method employs a systematic conformational search, followed by a potential energy surface (PES) expansion around each identified structure. This approach, which we termed Q/s, computes the nuclear partition function by assuming a harmonic PES and treats vibrational modes at a quantum mechanical level (with rotational and translational contributions considered semiclassically and classically, respectively). The second method, termed C/d, calculates populations by conducting a classical molecular dynamics (MD) simulation, thus treating nuclear motion fully classically.