像LDA, DFT, PAW, CGA (maybe wrong?), etc...

听过很多这些名词，也知道基本的意思，可是对于他们之间的从属关系一直是糊里糊涂的。哪位做计算的大牛能够帮忙解释一下，各种计算的basis，有缺点，它们之间的关系，等等。

以前一直以为LDA都是一样的，直到前几天和一个教授聊天，才知道LDA只是最基本的一种方法而已，就像spectroscopy。spectroscopy中有IR, UV, PL, 等等。LDA扩展下去会怎么样呢？

请教~~~

thanks

不是大牛，所以只是简单说说看我的理解：
LDA: local density approximation. LDA indicate any density functional theory where the value of ε(xc) at some position r could be computed exclusively from the value of ρ at that position
DFT: density functional theory
PAW: projector augmented wave (PAW) potentials? an all-electron DFT within the frozen core approximation
CGA: I guess this should be "GGA" which mean generalized gradient approximation. In GGA, correlation and exchange functional depends not only on the local value of the density, but on the extent to which the density is locally changing, i.e., the gradient of the density.

从属关系？都属于DFT，LDA是采用一种比较简单的方法来表示DFT里的Exchange-correlation Functionals, 这种方法有一定的缺陷。而GGA则是对LDA进行一些correction，现代计算程序中大部分采用的是GGA方法，最常用的exchange functionals比如B,CAM, FT97, O, PW, mPW,B86, LG, P, PBE, and mPBE。而常用的correlation functionals 有B88, P86, and PW91, LYP

Normally, we use Gassian (e.g. g03) or slater (e.g. ADF) functions as basis set, while CPMD, VASP, PAW use plane wave as a basis set instead. More faster!