School of Chemistry and Chemical Engineering and Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China.
State Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
J Phys Chem A. 2023 May 11;127(18):4027-4042. doi: 10.1021/acs.jpca.3c01065. Epub 2023 May 2.
The energy transfer, dissociations, and chemical reactions between O and N play an important role in the re-entry process of aircraft and many atmospheric, combustion, and plasma processes. Recently, Varga et al. (., , , 024310) developed a full-dimensional high-precision potential energy surface (PES) of the ground triplet electronic state for the O and N system based on ca. 55,000 data points, whose energies were calculated by multi-state complete-active-space second-order perturbation theory/minimally augmented correlation-consistent polarized valence triple-zeta electronic structure calculations plus dynamically scaled external correlation. The fitting function adopted the many-body expansion form with the four-body interactions fitted by the permutationally invariant polynomial in terms of bond-order functions of the six interatomic distances (MB-PIP). In this work, we refit the PES of the NO system by two methods based on the same data set that was used by Varga et al. The first uses the permutation invariant polynomial-neural network (PIP-NN) method to fit the entire energy of the 55,000 data points. In the second approach, the PIP-NN method is used to fit only the four-body interaction component, a similar treatment in the MB-PIP method, and the resulting PES is named MB-PIP-NN. Then, the performances of these new PESs and the MB-PIP PES are comprehensively and systematically compared, such as comparisons of various scans, properties of stationary points, and dynamics simulations. Possible improvements for the PES of NO are suggested. A more reliable PES of the system can be constructed in terms of data sampling range, electronic structure calculation level, and fitting method for high-temperature calculation and simulation in the future.
O 和 N 之间的能量转移、离解和化学反应在飞机再入过程以及许多大气、燃烧和等离子体过程中起着重要作用。最近，Varga 等人（.,,, 024310）基于约 55,000 个数据点，利用多态完全活性空间二级微扰理论/最小增强相关一致极化价三-zeta 电子结构计算加动态缩放外部相关，为 O 和 N 体系的基态三重电子态开发了一个全维高精度势能面（PES）。所采用的拟合函数采用多体展开形式，四体相互作用采用六原子间距离的置换不变多项式拟合（MB-PIP）的键序函数。在这项工作中，我们使用与 Varga 等人使用的相同数据集的两种方法重新拟合了 NO 体系的 PES。第一种方法使用置换不变多项式神经网络（PIP-NN）方法拟合 55,000 个数据点的整个能量。在第二种方法中，PIP-NN 方法仅用于拟合四体相互作用分量，类似于 MB-PIP 方法中的处理方式，所得 PES 命名为 MB-PIP-NN。然后，综合系统地比较了这些新 PES 和 MB-PIP PES 的性能，例如各种扫描、驻点性质和动力学模拟的比较。对 NO 的 PES 提出了可能的改进。可以根据数据采样范围、电子结构计算水平和拟合方法来构建更可靠的体系 PES，以便在未来进行高温计算和模拟。
