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标题: ZnCO3超胞之后结构优化没有收敛趋势 [打印本页]

作者
Author: Drizzy 时间: yesterday 13:32
标题: ZnCO3超胞之后结构优化没有收敛趋势
我在超胞之后加了一些水分子，参数设置的其实也不高，已经跑了四天左右了依旧没有收敛趋势，请老师们帮忙解答一下是哪里出了问题。目前已经跑了三十五个离子步。
INCAR参数
#SYSTEM =  qvasp
DFT-D3 Correction
IVDW =  12          (DFT-D3 method of method with no damping)

Global Parameters
ISTART =  0          (Read existing wavefunction, if there)
ISPIN  =  1          (Non-Spin polarised DFT)
# ICHARG =  11       (Non-self-consistent: GGA/LDA band structures)
LREAL  = Auto    (Projection operators: automatic)
ENCUT  =  450       (Cut-off energy for plane wave basis set, in eV)
# PREC =  Accurate (Precision level: Normal or Accurate, set Accurate when perform structure lattice relaxation calculation)
LWAVE  = F       (Write WAVECAR or not)
LCHARG = F       (Write CHGCAR or not)
ADDGRID= .TRUE.       (Increase grid, helps GGA convergence)
LASPH  = .TRUE.       (Give more accurate total energies and band structure calculations)
PREC = Accurate    (Accurate strictly avoids any aliasing or wrap around errors)
# 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)
# NWRITE = 2          (Medium-level output)
# KPAR = 2          (Divides k-grid into separate groups)
# NGXF = 300       (FFT grid mesh density for nice charge/potential plots)
# NGYF = 300       (FFT grid mesh density for nice charge/potential plots)
# NGZF = 300       (FFT grid mesh density for nice charge/potential plots)

Lattice Relaxation
NSW =  300       (number of ionic steps)
ISMEAR =  0          (gaussian smearing method )
SIGMA  =  0.1       (please check the width of the smearing)
IBRION =  2          (Algorithm: 0-MD, 1-Quasi-New, 2-CG)
ISIF =  2          (optimize atomic coordinates and lattice parameters)
POTIM  =  0.5
EDIFFG = -5E-02    (Ionic convergence, eV/A)
EDIFF = 1E-5
NELM = 100

POSCAR
smithnoite (1 0 4)
1.00000000000000
10.8310449999999996 0.0000000000000000 -9.9600270000000002
   0.0000000000000000 18.7599200000000010 0.0000000000000000
25.5534940000000006 0.0000000000000000 27.7881830000000001
H C O Zn
18 48 153 48

KPOINTS
K-Spacing Value to Generate K-Mesh: 0.040
0
Gamma
4 4 1
0.0  0.0  0.0

作者
Author: UW_0728. 时间: yesterday 14:16
这么大的体系VASP本来就不怎么跑得动；而且35个离子步这个数目也不算多，我遇到很多体系得一百多步甚至二百步才能收敛

作者
Author: Drizzy 时间: yesterday 14:23

UW_0728. 发表于 2026-2-17 14:16
这么大的体系VASP本来就不怎么跑得动；而且35个离子步这个数目也不算多，我遇到很多体系得一百多步甚至二百 ...

好的老师，我问了其他的老师说加上NPAR=2，然后prec=N，k点我自己的想法是弄成1×1×1，有参考文献是这样做的，不知道这样有没有用

作者
Author: UW_0728. 时间: yesterday 14:43

Drizzy 发表于 2026-2-17 14:23
好的老师，我问了其他的老师说加上NPAR=2，然后prec=N，k点我自己的想法是弄成1×1×1，有参考文献是这样 ...

考虑到你的体系里面有较多过渡金属Zn，个人认为k点设2*2*1最好，不过1*1*1（只考虑gamma点）也够用，可以接受；

NPAR这种参数对于改善VASP内部并行确实有用，但对于这么大体系效果并不显著，毕竟之所以耗时这么大显然八九成都是因为这个体系对于VASP来讲太大了；

结构优化任务中PREC应当保持原来的Accurate，避免用Normal，以防受力方面计算精度不够导致更大的几何优化难收敛问题；ADDGRID= .TRUE.可以去掉，能够节约一点耗时

作者
Author: Drizzy 时间: yesterday 14:48

UW_0728. 发表于 2026-2-17 14:43
考虑到你的体系里面有较多过渡金属Zn，个人认为k点设2*2*1最好，不过1*1*1（只考虑gamma点）也够用，可以 ...

好的，感谢老师

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