Extracting the electronic structure signal from X-ray and electron scattering in the gas phase
Extracting the electronic structure signal from X-ray and electron scattering in the gas phase
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DOI：
10.1107/s1600577524000067
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发表时间：
2024-03-01
影响因子：
2.5
通讯作者：
Weber，Peter M.
中科院分区：
文献类型：
--
作者：
Northey，Thomas;Kirrander，Adam;Weber，Peter M.
用独立原子模型(IAM)和从头算电子结构计算方法研究了自由气相分子的X射线和电子散射。IAM描述了分子几何对散射的影响，但没有考虑到价电子的重新分布，例如，化学键。通过研究氟仿(CHF_3)、1，3-环己二烯(C_6H_8)和萘(C_10H_8)三种分子的总散射，即能量积分散射，发现电子再分布效应主要存在于散射信号中动量传递的小到中等值(Q_≤_8_ ？−_1)，在2≤_Q_≤_3_ _−_1处贡献最大。这使得能够更清楚地识别在小Q和中等Q时散射与IAM近似的偏差，并提供价电子结构对散射信号影响的测量。
X-ray and electron scattering from free gas-phase molecules is examined using the independent atom model (IAM) and ab initio electronic structure calculations. The IAM describes the effect of the molecular geometry on the scattering, but does not account for the redistribution of valence electrons due to, for instance, chemical bonding. By examining the total, i.e. energy-integrated, scattering from three molecules, fluoroform (CHF3), 1,3-cyclohexadiene (C6H8) and naphthalene (C10H8), the effect of electron redistribution is found to predominantly reside at small-to-medium values of the momentum transfer (q ≤ 8 Å−1) in the scattering signal, with a maximum percent difference contribution at 2 ≤ q ≤ 3 Å−1. A procedure to determine the molecular geometry from the large-q scattering is demonstrated, making it possible to more clearly identify the deviation of the scattering from the IAM approximation at small and intermediate q and to provide a measure of the effect of valence electronic structure on the scattering signal.