<italic>Ab initio</italic>path-integral molecular dynamics and the quantum nature of hydrogen bonds

Ab initiopath-integral molecular dynamics and the quantum nature of hydrogen bonds

Feng Yexin¹, Chen Ji¹, Li Xin-Zheng^{2, 3, †,}, Wang Enge^{1, 3}

Illustration of how the mapping from the canonical quantum system to a classical polymer is done in the path-integral statistical mechanics. The polymer is composed ofPreplicas of the real molecule. In each replica, the potential is determined by the potential of the system at the specific spatial configuration of this replica. In between the replicas, the neighboring images (beads) of the same atoms are linked by springs. The spring constant is determined bym_jandω_Pas, where. Therefore, the higher the temperature and the heavier the nucleus, the stronger the interaction between the beads. In the limit ofT→ ∞ andm_j→ ∞, one arrives at the classical limit when all images overlap with each other. The partition function of the quantum system as shown on the left equals the configurational partition function of the polymer on the right asP→ ∞.