Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland.
Phys Chem Chem Phys. 2011 Jun 28;13(24):11678-85. doi: 10.1039/c1cp20295b. Epub 2011 May 19.
We report non-resonant inelastic X-ray scattering experiments of several gaseous samples in the inner-shell excitation energy range. The experimental near-edge spectra from all the K-edges of N(2), N(2)O, and CO(2) including the momentum transfer dependence are presented. The results are analyzed using density functional theory calculations that accurately reproduce the experimental spectral features. We observe vibrational effects in the measured spectrum and in the calculations the atomic motion is modeled using the Franck-Condon approximation and the linear coupling model. Our findings show that vibrational effects cannot be neglected in the analysis of high resolution inelastic X-ray scattering spectroscopy. The results also support the validity of the transition potential approximation for calculating core excited state potential energy surfaces.
我们报告了在原子内壳层激发能范围内几种气态样品的非共振非弹性 X 射线散射实验。给出了来自 N(2)、N(2)O 和 CO(2)所有 K 边的实验近边谱，包括动量转移依赖关系。使用密度泛函理论计算对结果进行了分析，该计算准确地再现了实验谱特征。我们观察到测量光谱中的振动效应，在计算中，原子运动使用 Franck-Condon 近似和线性耦合模型进行建模。我们的发现表明，在分析高分辨率非弹性 X 射线散射光谱时，振动效应不能被忽略。结果还支持了用于计算核心激发态势能面的跃迁势近似的有效性。
