Three‐dimensional accurate potential energy surfaces around the local minima of NO2− and NO2 were calculated with the SAC/SAC‐CI analytical energy gradient method. Therefrom, the ionization photoelectron spectra of NO2−, the equilibrium geometries and adiabatic electron affinity of NO2, and the vibrational frequencies including harmonicity and anharmonicity of NO2− and NO2 were obtained. The calculated electron affinity was in reasonable agreement with the experimental value. The SAC‐CI photoelectron spectra of NO2− at 350 K and 700 K including the rotational effects were calculated using the Franck–Condon approximation. The theoretical spectra reproduced well the fine experimental photoelectron spectra observed by Ervin et al. (J. Phys. Chem. 1988, 92, 5405). The results showed that the ionizations from many vibrational excited states as well as the vibrational ground state are included in the experimental photoelectron spectra especially at 700 K and that the rotational effects are important to reproduce the experimental photoelectron spectra of both temperatures. The SAC/SAC‐CI theoretical results supported the analyses of the spectra by Ervin et al., except that we could show some small contributions from the asymmetric‐stretching mode of NO2−. © 2018 Wiley Periodicals, Inc.

中文翻译：

---

NO2 - 的光电子谱：振动-旋转结构的 SAC-CI 梯度研究

使用 SAC/SAC-CI 分析能量梯度方法计算了 NO2− 和 NO2 局部最小值周围的三维精确势能面。由此，获得了NO2-的电离光电子谱、NO2的平衡几何结构和绝热电子亲和势，以及NO2-和NO2的谐波和非谐波振动频率。计算的电子亲和力与实验值合理一致。使用 Franck-Condon 近似计算 NO2− 在 350 K 和 700 K 下的 SAC-CI 光电子谱，包括旋转效应。理论光谱很好地再现了 Ervin 等人 观察到的精细实验光电子光谱。(J. Phys. Chem. 1988, 92, 5405)。结果表明，来自许多振动激发态和振动基态的电离都包含在实验光电子谱中，尤其是在 700 K 时，并且旋转效应对于再现两种温度的实验光电子谱很重要。SAC/SAC-CI 理论结果支持 Ervin 等人的光谱分析，除了我们可以显示 NO2− 的不对称拉伸模式的一些小的贡献。© 2018 Wiley Periodicals, Inc. 除了我们可以展示 NO2− 的不对称拉伸模式的一些小的贡献。© 2018 Wiley Periodicals, Inc. 除了我们可以展示 NO2− 的不对称拉伸模式的一些小的贡献。© 2018 Wiley Periodicals, Inc.