求助审稿人问Cp2k跑AIMD模拟过程中自旋状态的处理和泛函选择的回复

吞木木

各位老师好，
    我之前用Cp2K跑了几段高温NVT系综的长时间的AIMD（基于PBE纯泛函）的模拟，同时结合Gaussian进行了一些量化计算（基于M062X混合泛函），手稿投出去后审稿人关于模拟的方法和技术问题提出了几个“致命性”的技术问题，我并不知道怎么回复这些问题，还望各位老师给几个建议。


    问题1：动力学计算和量化计算泛函选择不同的问题，详情如下：
    One weak point of the paper is that the Gaussian calculations are performed using a different functional and temperature. The temperature is not the real problem, since the Gaussian calculations only take T to make the typical corrections in the rigid rotor/harmonic oscillator approximation. The main issue is the choice of the functional. M062X is a hybrid functional, while PBE (used in the MD simulations)is a pure GGA functional.
    问题2：跑AIMD模拟过程中自旋状态的如何处理的问题，详情如下：
    Another technical point I am not sure is the way in which the ab initio MD simulations performed using CP2K deal with spin states. I guess that the authors start their simulations with a closed shell system S=0. However, along the simulation radical species appear. I am not sure how CP2K deals with this situation. In localized basis sets codes this would mean that the system would evolve as an open shell singlet state (meaning that the overall spin state is kept equal to 0). However, DFT may fail in describing the electronic structure of those complex systems. I am not an expert in CP2K type simulations, so I am not sure about how this issue should be handled. If spin states occur in the process an adiabatic simulation, such as the ones performed in the paper, are completeley inadequate.

    希望各位老师能够给出几点建议帮助学生回答这两个问题，感谢感谢！

sobereva

1 说清楚换泛函的理由。杂化泛函跑AIMD过于昂贵，而当前泛函跑AIMD精度又已经够了，算单点用更好的泛函有充分的理由
参考下文
量子化学研究中切换泛函应当注意的问题
http://sobereva.com/415（http://bbs.keinsci.com/thread-9878-1-1.html）

2 没体系信息没法说。如果模拟过程中确实可能出现对称破缺状态，需要考虑审稿人说的问题。注意并不是模拟过程中断键就一定会经历对称破缺态，诸如闭壳层体系涉及成键-断键的化学反应的过渡态大多也不是对称破缺态。

吞木木

sobereva 发表于 2024-9-20 18:32
1 说清楚换泛函的理由。杂化泛函跑AIMD过于昂贵，而当前泛函跑AIMD精度又已经够了，算单点用更好的泛函有充 ...

感谢卢天老师的耐心回复，对学生帮助很大