[交流] 【求助】charge population

A disadvantage of the use of a plane wave (PW) basis set is that, due to the delocalized nature of the basis states, it provides no information regarding the localization of the electrons in the system. In contrast, a Linear Combination of Atomic Orbitals (LCAO) basis set provides a natural way of specifying quantities such as atomic charge, bond population, charge transfer etc.

Population analysis in CASTEP is performed using a projection of the PW states onto a localized basis using a technique described by Sanchez-Portal et al. (1995). Population analysis of the resulting projected states is then performed using the Mulliken formalism (Mulliken, 1955). This technique is widely used in the analysis of electronic structure calculations performed with LCAO basis sets.

Originally posted by xuelian172 at 2010-11-22 16:11:55:
请教：我看文献怎么分析的都有了，说charge population不能有负值，还有的说负值的意思是离子键，请大侠们告诉我一下，charge population 的定义是什么？到底是怎么一回事？？