二己二硫醚多层膜局域结构的近边x射线吸收精细结构研究

Near edge x-ray absorption fine structure studies of local structure of dihexyldisulfide multilayer

利用多重散射团簇(MSC)方法计算了二己二硫醚[CH3(CH2)5S]2单分子和多分子硫原子近边x射线吸收精细结构(NEXAFS)谱,给出了二己二硫醚多层膜的局域结构模型.MSC研究显示多层膜中二己二硫醚分子作平行有序排列,彼此相距0.47nm,其横截面呈规则的正方形.利用离散变分Xα方法计算了二己二硫醚单分子和多分子的电子结构,验证了MSC的计算结果;并阐明了NEXAFS谱中各峰的物理起源.对多层膜中分子之间的相互作用进行了讨论,发现多层膜的局域结构有分子自组装的特性.

The multiple-scattering cluster （MSC） method is employed to calculate the S Is near edge x-ray absorption fine structure （NEXAFS） of single dihexyldisulfide molecule and dihexyldisulfide multilayer. The local structure model of the dihexyldisulfide multilayer is proposed. The MSC calculation shows that the neighboring dihexyldisulfide molecules are parallelly arranged in an ordered square cross section with side of 0.47 nm. The discrete variational Xα method is employed to calculate the electronic structure of the single molecule and muhilayer, which confirms the MSC results, and reveals the physical origin of all the features in the S Is NEXAFS spectrum. The analysis of the interaction between the dihexyldisulfide molecules shows that the local structure of the multilayer has the property of self-assemblage.