ABINIT-PAW方法使用（1）

PAW方法参考文献；

[1] "Projector augmented-wave method", P.E. Blochl, Physical Review B 50, 17953 (1994)
[2] "From ultrasoft pseudopotentials to the projector augmented-wave method", G. Kresse and D. Joubert, Physical Review B 59, 1758 (1999)

The implementation of the PAW method in ABINIT is detailed in the following paper, describing specific notations and formulations:

[3] "Implementation of the projector augmented-wave method in the ABINIT code: Application to the study of iron under pressure", M. Torrent, F. Jollet, F. Bottin, G. Zerah, and X. Gonze, Computational Materials Science 42, 337 (2008)  

PAW在ABINIT上使用需要指定特殊指定pawecutdg

pawecutdg
Mnemonics: PAW - Energy CUToff for the Double Grid
PAWECUTDG  必须大于等于ECUT，对于典型的PAW计算，如果ECUT 取15的数量级，PAWECUTDG应该在40左右的量级，选用更大的PAWECUTDG 不会显著增加计算时间，只会增加内存。并且如果ECUT足够大，不必设定一个较大的PAWECUTDG。

PAWECUTDG总需要做收敛测试，大小一般取为至少两倍得的ECUT,并且在计算中保持不变。

与PAWECUTDG相联系的是 ngfftdg

PAWECUTDG-----Define the energy cut-off for the fine FFT grid---截断能

NGFFTDY----- Number of Grid points for Fast Fourier Transform---格点数

PAW输入变量

Looking at the ~abinit/doc/input_variables/varbas.html file, you can find input ABINIT keywords specific to PAW. They are to be used when tuning the computation, in order to gain accuracy or save CPU time.
Warning : in a standard computation, these variables should not be modified !

Variables that can be used to gain accuracy (in ascending order of importance):

pawxcdev: control the accuracy of exchange-correlation on-site potentials (try pawxcdev=2 to increase accuracy).
mqgriddg: control the accuracy of spline fits to transfer densities/potentials from FFT grid to spherical grid.
pawnzlm: control the computation of moments of spherical densities that should be zero by symmetry.

Variables that can be used to save memory (in ascending order of importance):

pawstgylm: control the storage of spherical harmonics computed around atoms.

pawmixdg: control on which grid the potential/density is mixed during SCF cycles.
pawlcutd: control the number of angular momenta to take into account in on-site densities.
pawlmix: control the number of ρ_ij to be mixed during SCF cycle.

Variables that can be used to save CPU time (in ascending order of importance):

pawnhatxc: control the numerical treatment of gradients of compensation charge density in case of GGA
pawstgylm: control the storage of spherical harmonics computed around atoms.
pawlcutd: control the number of angular momenta to take into account in on-site densities.
pawlmix: control the number of ρ_ij to be mixed during SCF cycle.
bxctmindg: can be used to decrease the size of fine FFT grid for a given value of pawecutdg.

7.e PAW+U

本文纯属自学只用，可能很多错误。。。误导嫌疑，本人概不负责。