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子虚乌有5388

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[交流] 【其他】关于GW(准粒子计算能带结构等)方法的工作 已有6人参与

想做关于准粒子计算能带,激发态,光谱等的工作,大家讨论下,这个算起来是不是很费劲?目前能算准粒子的软件可算多大体系?
另外这方面工作少的原因是不是和计算很耗时间有关系?

谢谢大家指点讨论!
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sweetwind88

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子虚乌有5388(金币+1): 2010-08-03 12:45:35
xiaohunhun(金币+1):xiexie 2010-08-05 20:58:48
是非常耗时的事情。
change
3楼2010-08-03 00:09:22
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hedaors

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子虚乌有5388(金币+1):我打算计算光吸收谱 要用到这个 看来只能罢手了 2010-08-02 23:25:50
qasd(金币+1):谢谢 2010-08-03 07:25:41
这个非常耗时。

并不是所有工作都必须要用 gw 近似的,由于计算量太大,所以一般非必须的话都不会算。
2楼2010-08-02 23:24:07
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fzx2008

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子虚乌有5388(金币+1): 2010-08-03 22:28:06
xiaohunhun(金币+1):xiexie 2010-08-05 20:57:30
体系稍大点都算不动!
6楼2010-08-03 21:04:40
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xiaomagh

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★ ★
子虚乌有5388(金币+1): 2010-08-08 18:26:05
zzy870720z(金币+2):谢谢分享 2010-08-08 18:47:40
我看到过一个计算的例子 , 贴给大家看看。

-------------------------------------------------------------------------
GW Band Structure Plots
To obtain band structure plots from the GW method, first you have to perform a
DFT calculation. The INCAR file I used for DFT on Si looks like this:
ISTART = 0
ISYM = 0
ICHARG = 2
ISMEAR = 0
SIGMA = 0.1
LORBIT = 11
NSW = 200
IBRION = 2
ISIF = 3
EDIFF = 0.0001
EDIFFG = -0.01

KPOINTS file for the run is:
Monkhorst Pack
0
Gamma
4 4 4
0 0 0

POSCAR file is:
Si
5.38936000000000
0.5000000000000000 0.5000000000000000 0.0000000000000000
0.0000000000000000 0.5000000000000000 0.5000000000000000
0.5000000000000000 0.0000000000000000 0.5000000000000000
2
Direct
0.0000000000000000 0.0000000000000000 0.0000000000000000
0.2500000000000000 0.2500000000000000 0.2500000000000000
POTCAR file is supplied with VASP 5.2, remember to use paw pseudopotentials so that in the band structure calculation the Wigner-Seitz radius for Si need not be directly specified in INCAR.

After this run completes you are ready to perform the HF-type (HSE06)
calculation. Change the INCAR file to:
ISTART = 1
ICHARG = 2
EDIFF = 0.0001
EDIFFG = -0.01
ENCUT = 400
ENAUG = 800
LREAL = .FALSE.
LWAVE = .TRUE.
LCHARG = .TRUE.
NELM = 200
NSW = 0
IBRION = -1
LMAXMIX = 4
ISMEAR = 0
SIGMA = 0.1
NSIM = 4
IALGO = 48
ISYM = 0
LHFCALC = .TRUE.
HFSCREEN = 0.2
ALGO = Damped
TIME = 0.4
ENCUTFOCK = 0
NKRED = 2
AEXX = 0.25

Keep the other files constant for this run (e.g. KPOINTS, POSCAR, POTCAR need not be changed).
Once this run has completed, add to the bottom of the INCAR file from the HSE06 calculation:
LOPTICS = .TRUE.
This step calculates the dielectric matrix Once this run has completed, change ALGO = Damped to ALGO = Gwo and
ICHARG = 2 to ICHARG = 11 and add:
NOMEGA = 50
ENCUTGW = 100
LORBIT = 11
and change the KPOINTS file to:
k-points along high symmetry lines
20 ! 20 intersections
Line-mode
rec
0 0 0 ! gamma
0.5 0.0 0 ! X
0.5 0.0 0 ! X
0.5 0.5 0.0 ! M
0.5 0.5 0.0 ! M
0.0 0.0 0.0 ! gamma
0.0 0.0 0.0 ! gamma
0.5 0.5 0.0 ! M
0.5 0.5 0.0 ! M
0.5 0.5 0.5 ! R
0.5 0.5 0.5 ! R
0.0 0.0 0.0 ! gamma
These values are the points of high symmetry along the lines of high symmetry
within the first Brillouin Zone of the Si unit cell structure in reciprocal space. And that’s it! Once complete you can plot the PROCAR, EIGENVAL, and DOSCAR files from the output of this run as described in the previous posts. The band structure plot produced from the plotting utility is shown below.

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7楼2010-08-08 12:35:34
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