Nitrous Oxide, And Two Had Two Sulfide Molecules Nexafs Study Of Self-assembly

NEXAFS (Near-edge X-rays Absorption Fine Structure) is a reliable method in studying the atomic and electronic structure of the condensed matter, especially for the disorder system, in which it has been identified as the "fingerprint analysis" of the local structure, and exhibits itself a high precision. The method is suitable for studying the local structure of the molecular self-assembly system. In this paper, we mainly utilize the multiple-scattering cluster (MSC) and DV-Xa methods to approach the NEXAFS spectra for the N2O multilayer and the N2O adsorbed on the Cu(100) and Ag(110) surfaces, and obtain their atomic structures and electronic states information. As for the N2O multilayer, the MSC calculation shows that it is a self-assembly system. Due to the electric and covalent interaction the N2O molecules make up a parallel dislocation chain. The molecular chains form a stable single layer by the coupling each other. At last the molecular layers stack one by one, thereupon become into a N2O multilayer by the electric and covalent interaction. Optimizetion calculation shows that the distance between the neighbor molecular layers (0.240 nm) is close to the distance between the neighbor molecules (0.238 nm) in the same molecular chain. They display the same characteristics. But the distance between the neighbor molecular chains is 0.478 nm, which is much bigger than the distance between the molecular layers, and this fact implies that the molecular chains in the same layer are coupling by the weak Van de Waals force. The MSC and DV-Xa methods have been employed to analyze the physical origin of all resonances in N 1 s NEXAFS spectrum of the N2O multilayer, in which the two intense peaks are both theπresonances, after these there are five weak features, named as s1,σ, s2, w1 and w2, in which the weak featuresσand w2 are both theσ-resonances, while the other weak features don't correspond to the LUMOs, which are all the satellites of the peaks 1 and 2 due to the shake up effect of the N nuclei in the N2O molecules. Furthermore, the ionic potential of the N2O molecular self-assembly layer seriously weakens theσresonance, and makes it to be a weak feature. As to the N2O/Cu(100) and N2O/Ag(110) systems, we find that they are both the weak molecule adsorbption systems. The adsorption model of them are the same each other, that is, the NT atom of the N2O molecule attachs the surface. The conclusion is different from that of mentioned by Ceballos et al.As to dihexyldisulfide multilayer, we find that the linear dihexyldisulfide molecules are arranged in parallel each other, and show the cross section just like the (100) face. The distance between the neighbor molecules is 0.47 nm, so the interaction between them is only the weak Van de Waals force, which makes the dihexyldisulfide multilayer to be a stable molecular self-assembly system.