N2O多层膜局域结构的多重散射簇理论研究

利用多重散射簇(multiple scattering cluster, MSC)方法计算了N2O多层膜中氮原子的1s芯态近边X射线吸收精细结构(near edge X-ray absorption fine structure, NEXAFS)谱,首次给出N2O多层膜局域结构的模型. MSC研究显示多层膜中N2O分子以短程有序的分层错位链结构排列,并求得链中相邻分子间距为0.233 nm和相邻分子层之间距离为0.240～0.245 nm.用自洽场离散变分(discrete variation, DV)Xα方法计算的N2O多层膜电子结构支持了MSC的计算结果;阐明了NEXAFS谱中弱结构的物理起源.对N2O多层膜中分子之间相互作用的分析显示N2O多层膜的结构具有分子自组装的特性.

Theoretical Studies of Multiple-scattering-cluster Theory of Local Structure of N2O Multilayer

The multiple-scattering-cluster(MSC) method has been employed to calculate the nitrogen 1s near edge X-ray absorption fine structure(NEXAFS) of the N2O multilayer. The local structure model of the N2O multilayer has been proposed for the first time. The MSC calculation shows that the N2O molecules in the multilayer are arranged as layered dislocation chains, which show a short-range order. The distances between the neighbor molecules and between the neighbor molecular layers are equal to 0.233 nm and 0.240～0.245 nm, respectively. The self-consistent field (SCF) DV-Xα method has been employed to calculate the electronic structure of the N2O multilayer, which confirms the MSC results, and reveals the physical origin of the weak features in the N 1s NEXAFS spectrum. The analysis of the interaction between the N2O molecules has shown that the structure of the N2O multilayer shows a self-assembly characteristic.