Inkinen Juho, Niskanen Johannes, Sakko Arto, Ruotsalainen Kari O, Pylkkänen Tuomas, Galambosi Szabolcs, Hakala Mikko, Monaco Giulio, Hämäläinen Keijo, Huotari Simo
Department of Physics, University of Helsinki , P.O. Box 64, FI-00014 Helsinki, Finland.
J Phys Chem A. 2014 May 8;118(18):3288-94. doi: 10.1021/jp5019058. Epub 2014 Apr 28.
We report a study on the temperature dependence of the valence electron excitation spectrum of CO2 performed using nonresonant inelastic X-ray scattering spectroscopy. The excitation spectra were measured at the temperatures of 300 and 850 K with momentum-transfer values of 0.4-4.8 Å(-1), i.e., from the dipole limit to the higher-multipole regime, and were simulated using high-level coupled cluster calculations on the dipole and quadrupole level. The results demonstrate the emergence of dipole-forbidden excitations owing to temperature-induced bending mode activation and finite momentum transfer.
我们报告了一项利用非共振非弹性X射线散射光谱法对二氧化碳价电子激发光谱的温度依赖性进行的研究。激发光谱是在300和850 K的温度下，动量转移值为0.4 - 4.8 Å⁻¹（即从偶极极限到更高多极子区域）时测量的，并使用偶极和四极水平的高级耦合簇计算进行了模拟。结果表明，由于温度诱导的弯曲模式激活和有限的动量转移，出现了偶极禁戒激发。
