Department of Physics, University of Helsinki, Helsinki, Finland.
Phys Chem Chem Phys. 2013 Jun 21;15(23):9231-8. doi: 10.1039/c3cp50512j. Epub 2013 May 8.
We report a study on the temperature dependence of the core-electron excitation spectra of CO2 and N2, performed using non-resonant inelastic X-ray scattering spectroscopy. The spectra were measured at two temperatures (300 K and 850 K) and at high pressure (40 bar). For CO2 a clear temperature dependence was observed at the C and O near-edge regions. The spectra of CO2 were simulated by density functional theory calculations, and the temperature was accounted for by sampling the initial state molecular geometries using the Metropolis algorithm. This model is able to account for the experimentally observed temperature dependence of the spectrum. The experiment fortifies the status of the non-resonant inelastic X-ray scattering spectroscopy as a valuable technique for physics and chemistry for in situ studies under extreme sample conditions. Especially in the case of gas phase the sample conditions of considerably elevated temperature and pressure are unfeasible for many other spectroscopic techniques.
我们报告了一项关于 CO2 和 N2 芯电子激发谱随温度变化的研究，该研究使用了非共振非弹性 X 射线散射光谱学。在两种温度（300 K 和 850 K）和高压（40 巴）下测量了光谱。对于 CO2，在 C 和 O 近边区域观察到了明显的温度依赖性。通过密度泛函理论计算模拟了 CO2 的光谱，并通过使用 Metropolis 算法对初始状态分子几何形状进行抽样来考虑温度。该模型能够解释实验观测到的光谱随温度的变化。该实验巩固了非共振非弹性 X 射线散射光谱学作为一种在极端样品条件下进行物理和化学原位研究的有价值技术的地位。特别是在气相的情况下，对于许多其他光谱技术来说，温度和压力都显著升高的样品条件是不可行的。
