Newton-X contains a method to correct zero-point-energy (ZPE) leakage, the local-pair (LP) ZPE correction. The method is tailored for on-the-fly propagation and does not require Hessian matrices, which are too expensive to be tracked during dynamics. LP-ZPE monitors the mean kinetic energy of high-frequency atom pairs instead of the normal modes. If this mean value drops below a threshold, the pair is topped up with energy pumped from other pairs.