The problem associated with the zero-point energy (ZPE) leak in classical trajectory calculations is well known. Since ZPE is a manifestation of the quantum uncertainty principle, there are no restrictions on energy during the classical propagation of nuclei. This phenomenon can lead to unphysical results, such as forming products without the ZPE in the internal vibrational degrees of freedom (DOFs). The ZPE leakage also permits reactions below the quantum threshold for the reaction. We have developed a new Hessian-free method, inspired by the Lowe-Andersen thermostat model, to prevent energy dipping below a threshold in the local-pair (LP) vibrational DOFs. The idea is to pump the leaked energy to the corresponding local vibrational mode taken from the other vibrational DOFs. We have applied the new correction protocol on the ab-initio ground-state molecular dynamics simulation of the water dimer (H₂O)₂, which dissociates due to unphysical ZPE spilling from high-frequency OH modes. The LP-ZPE method has been able to prevent the ZPE spilling of the OH stretching modes by pumping back the leaked energy into the corresponding modes, while this energy is taken from the other modes of the dimer itself, keeping the system as a microcanonical ensemble.

中文翻译：

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防止经典轨迹中零点能量泄漏的无 Hessian 方法

与经典轨迹计算中的零点能量 (ZPE) 泄漏相关的问题是众所周知的。由于 ZPE 是量子不确定性原理的体现，因此在原子核的经典传播过程中对能量没有限制。这种现象会导致非物理结果，例如在内部振动自由度 (DOF) 中形成没有 ZPE 的产品。ZPE 泄漏还允许反应低于反应的量子阈值。我们开发了一种新的无 Hessian 方法，受 Lowe-Andersen 恒温器模型的启发，以防止能量下降到局部对 (LP) 振动自由度的阈值以下。这个想法是将泄漏的能量泵送到从其他振动自由度获取的相应局部振动模式。₂ O) ₂，由于非物理 ZPE 从高频 OH 模式溢出而解离。LP-ZPE 方法已经能够通过将泄漏的能量泵回相应的模式来防止 OH 拉伸模式的 ZPE 溢出，而这种能量来自二聚体本身的其他模式，使系统保持为微规范系综.