报 告 人：美国劳伦斯－伯克利国家实验室 Xiaosong Liu博士
报告题目："Explore the Electronic and Structural Properties of Tailored Surfaces with Soft X-Ray Spectroscopy"
Abstract: Surface science has made great strides towards tailoring surface properties via self-assembly organic molecules. It is now possible to functionalize surfaces with complex biomolecules, such as DNA, peptides and proteins. However, probes of the chemical orbitals involved in this process have remained scarce. I will show how NEXAFS (Near Edge X-ray Absorption Fine Structure spectroscopy) can be used to characterize the assembly of biological molecules at surfaces in atom- and orbital-specific fashion. The technique is illustrated by self-assembled monolayers with customized terminal groups. Applications are demonstrated by Ribonuclease A, a small protein containing 124 amino acids. The N 1s absorption edge is particularly useful for characterizing proteins, because it selectively interrogates the PI* orbitals in nucleobases and the peptide bonds in proteins. Information about the orientation of molecular orbitals is obtained from the polarization dependence of NEXAFS. Quantitative models are developed to explain the polarization dependence in terms of molecular orientation and structure.
I may also present some new work of biomimetic dyes solar cell in time allows.