The QQ part represents the photoionization cross-sections of an isolated atom, while the CQ part (the DIF) may represent most of the important influence of the macroscopic effects, e.g.

• 创建高密度体系中原子或分子精确的光电离截面表达式以及表征体系宏观介电性质和粒子之间的相互作用对原子或分子光电离截面影响程度的介电影响函数是本课题研究的主要目的和创新点。