一种测量吸附分子列向的方法——利用近阈结构谱和选择定则

局域分子轨道不易受环境影响，因此当分子被吸附且未被破坏时，跃迁到局域分子轨道产生的近阈结构谱基本不受环境影响.对于固定列向的吸附分子，当用偏振X射线测量其近阈结构谱时，相对强度将与偏振方向和分子列向有关.根据这一特性，基于选择定则可以判断吸附分子的列向. 关键词： 量子数亏损理论 近阈结构 选择定则 分子列向

A method to determine the orientations of adsorbed molecules by near edge structures and selection rules

Since non-diffuse molecular orbitals （NMOs） are insensitive to environment，when molecules are adsorbed and not broken，the near edge structures involving NMOs will still resemble structures of corresponding free molecules. If we probe adsorbed molecules with polarized X-ray photons，relative intensities of photoabsorption spectra near molecular edges will be different for various geometric arrangement of X-ray polarization. Such features can be used to determine orientations of adsorbed molecules.