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标题: 使用VASP进行结构优化结构不收敛和DOS计算态密度曲线不对 [打印本页]

作者
Author: qmingD 时间: 2024-9-22 14:42
标题: 使用VASP进行结构优化结构不收敛和DOS计算态密度曲线不对
各位老师好！我所计算的结构是Na4Fe3(PO4)2P2O7，在结构优化的过程当中容易出现力收敛的值忽大忽小的问题，要么就是花费很长时间结构也收敛不了。最后就算是结构收敛了算出来的DOS图形状和文献上的对比也不太对，想请教一下大家接下来该怎样优化。
下面是我的所使用的INCAR
ISTART =  0          (Read existing wavefunction; if there)
ISPIN =  2          (Spin polarised DFT)
ICHARG =  2       (Non-self-consistent: GGA/LDA band structures)
LREAL  = Auto       (Projection operators: automatic)
ENCUT  =  520       (Cut-off energy for plane wave basis set, in eV)
PREC =  N    (Precision level)
LWAVE  = .F.       (Write WAVECAR or not)
LCHARG = .F.       (Write CHGCAR or not)
ADDGRID= .TRUE.       (Increase grid; helps GGA convergence)
# LVTOT  = .TRUE.    (Write total electrostatic potential into LOCPOT or not)
# LVHAR  = .TRUE.    (Write ionic + Hartree electrostatic potential into LOCPOT or not)
# NELECT =          (No. of electrons: charged cells; be careful)
# LPLANE = .TRUE.    (Real space distribution; supercells)
NPAR = 4          (Max is no. nodes; don't set for hybrids8
NCORE = 4
# NWRITE = 2          (Medium-level output)
# KPAR = 2          (Divides k-grid into separate groups
# NGX = 500       (FFT grid mesh density for nice charge/potential plots)
# NGY = 500       (FFT grid mesh density for nice charge/potential plots)
# NGZ = 500       (FFT grid mesh density for nice charge/potential plots)
#NBANDS = 550

ISIF =  3          (Stress/relaxation: 2-Ions, 3-Shape/Ions/V, 4-Shape/Ions)
Electronic Relaxation
ISMEAR = 0          (Gaussian smearing; metals:1)
SIGMA  =  0.2       (Smearing value in eV; metals:0.2)
NELM =  300          (Max electronic SCF steps)
#NELMIN =  6          (Min electronic SCF steps)
EDIFF  =  1E-06       (SCF energy convergence; in eV)
#GGA  =  PS          (PBEsol exchange-correlation)
AMIX = 0.2

Ionic Relaxation
ISYM = 0
#IMAGES = 5
NSW = 200       (Max electronic SCF steps)
IBRION = 1          (Algorithm: 0-MD; 1-Quasi-New; 2-CG)
#LAECHG = .T.
#POTIM = 0
#ICHAIN=0
#LCLIMB=.T.
#LNEBCELL = .TRUE.
#IOPT= 3
EDIFFG = -0.02    (Ionic convergence; eV/AA)
# ISM =  2          (Symmetry: 0=none; 2=GGA; 3=hybrids)
ALGO = N
IVDW = 11
#LMAXMIX = 4
DFT+U Calculation
LDAU = .TRUE.       (Activate DFT+U)
LDATYPE=  2          (Dudarev; only U-J matters)
LDAUL  = 0 2 0 0       (Orbitals for each species)
LDAUU  =  0 4.9 0 0       (U for each species)
LDAUJ  =  0 0 0  0    (J for each species)
LMAXMIX=  4          (Mixing cut-off; 4-d, 6-f)
MAGMOM= 16*0.6 12*5.0 16*0.6 60*0.6

作者
Author: 1372133091 时间: 2024-9-29 11:29
本帖最后由 1372133091 于 2024-9-29 11:46 编辑

可以尝试输入合适的NEDOS值，例如“NEDOS=1000”，具体情况要根据得出的DOS判断

作者
Author: qmingD 时间: 2024-9-29 21:00

1372133091 发表于 2024-9-29 11:29
可以尝试输入合适的NEDOS值，例如“NEDOS=1000”，具体情况要根据得出的DOS判断

好的感谢！这个nedos会对dos的峰图形状有影响是吗

作者
Author: 1372133091 时间: 2024-9-29 22:23

qmingD 发表于 2024-9-29 21:00
好的感谢！这个nedos会对dos的峰图形状有影响是吗

是的，VASP-viki中有相关解释https://www.vasp.at/wiki/index.php/NEDOS

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