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各位大佬:
新手问题多多,遇到一个12年一个同学在小*虫一样的问题(http://mu****g.com/t-4798737-1),但是没有找到解决办法,请大家帮忙看看。
我用一天锐钛矿tio2做测试,发现力没有达到收敛标准,就提示已经达到了收敛精度,并且停止了。如下:
程序结束提示达到收敛标准
2 F= -.10740797E+03 E0= -.10740797E+03 d E =-.776677E+00
trial-energy change: -0.776677 1 .order -0.850772 -1.729269 0.027725
step: 0.9790(harm= 0.9842) dis= 0.09998 next Energy= -107.408261 (dE=-0.777E+00)
bond charge predicted
N E dE d eps ncg rms rms(c)
DAV: 1 -0.107408172007E+03 -0.20244E-03 -0.21718E-01 9600 0.175E+00 0.755E-02
DAV: 2 -0.107408290460E+03 -0.11845E-03 -0.19065E-03 17920 0.202E-01 0.439E-02
DAV: 3 -0.107408258465E+03 0.31996E-04 -0.82213E-05 11584 0.436E-02 0.198E-02
DAV: 4 -0.107408256735E+03 0.17296E-05 -0.39445E-05 18048 0.288E-02 0.698E-03
DAV: 5 -0.107408256291E+03 0.44422E-06 -0.40044E-06 10304 0.901E-03 0.339E-03
DAV: 6 -0.107408256218E+03 0.72734E-07 -0.58195E-07 16832 0.396E-03 0.502E-04
DAV: 7 -0.107408256251E+03 -0.33053E-07 -0.24497E-08 10880 0.818E-04 0.203E-04
DAV: 8 -0.107408256265E+03 -0.14161E-07 -0.90587E-10 6272 0.170E-04 0.748E-05
DAV: 9 -0.107408256268E+03 -0.26193E-08 -0.29326E-10 4864 0.943E-05
3 F= -.10740826E+03 E0= -.10740826E+03 d E =-.776963E+00
curvature: -0.44 expect dE=-0.631E-07 dE for cont linesearch -0.631E-07
trial: gam=-0.00029 g(F)= 0.144E-06 g(S)= 0.000E+00 ort = 0.499E-03 (trialstep = 0.996E+00)
search vector abs. value= 0.100E-09
reached required accuracy - stopping structural energy minimisation
vaspkit 产生的incar 和我自己写的incar结果一样
Global Parameters
ISTART = 1 (Read existing wavefunction, if there)
ISPIN = 1 (Non-Spin polarised DFT)
# ICHARG = 11 (Non-self-consistent: GGA/LDA band structures)
LREAL = .FALSE. (Projection operators: automatic)
# ENCUT = 400 (Cut-off energy for plane wave basis set, in eV)
# PREC = Normal (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 hybrids)
# 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)
Electronic Relaxation
ISMEAR = 0 (Gaussian smearing, metals:1)
SIGMA = 0.05 (Smearing value in eV, metals:0.2)
NELM = 90 (Max electronic SCF steps)
NELMIN = 6 (Min electronic SCF steps)
EDIFF = 1E-05 (SCF energy convergence, in eV)
# GGA = PS (PBEsol exchange-correlation)
Ionic Relaxation
NSW = 100 (Max ionic steps)
IBRION = 2 (Algorithm: 0-MD, 1-Quasi-New, 2-CG)
ISIF = 2 (Stress/relaxation: 2-Ions, 3-Shape/Ions/V, 4-Shape/Ions)
EDIFFG = -1E-02 (Ionic convergence, eV/AA)
# ISYM = 2 (Symmetry: 0=none, 2=GGA, 3=hybrids)
我的incar
SYSTEM= tio2 OPT #第一行为注释行
ISTART = 0 #如何生成波函数,首次结构优化用0。如果进行能带、电子结构计算,使用ISTART=1(读取优化的波函数,比CHGCAR快),ICHARG=11
ICHARG = 2 #如何获得初始电荷密度,首次结构优化用2,通过原子电荷叠加初猜电荷密度。算能带和dos需要用11,读取前面的CHGCAR
LWAVE = .FALSE.
LCHARG = .FALSE.
ISMEAR = 0 #决定电子轨道分数占据。0适用于导体、半导体和绝缘体.
#对于金属体系来说,也可以使用ISMEAR = 1,SIGMA = 0.01
#算dos时,ISMEAR =-5(K大于4),可以得到一个非常平滑的DOS图
#如果体系很大,只能适用gamma点来算,可以使用ISMEAR = 0;SIGMA = 0.01。
SIGMA = 0.05 #展宽默认为0.2.对于半导体和绝缘体,k小于4,sigma可以取小点,比如0.01-0.05。对于金属,取0.1足够。对于分子取0.02
LREAL = F #Default= .FALSE.,精确就用倒空间,不要求就实空间.超过20个原子都推荐设。true比较保险,不容易出错
ENCUT = 400 #截断能, ENCUT的最小值应为所有元素中ENMAX的最大值或1.3倍左右.第一次为了获得稳定的晶格常数,可以设置为600
EDIFF = 1E-05 # 能量收敛标准ev.结构优化的时候,EDIFF=1E-5, EDIFFG =-0.01 至 -0.03 都是被认可的
NELM = 60
ALGO = Normal #不写就默认为Normal,DAV算法,收敛性好,但速度慢.结构好可以用Fast
IBRION = 2 #2代表离子原子位置优化.不写就默认为-1,即原子位置不优化,一般1用于静态计算
POTIM = 0.1 # 离子移动步距,一般在0.1——0.5间.如果初始结构很差,设置较小的POTIM可以有效的避免过度矫正,比如0.01
ISIF = 2 #2代表只优化原子位置,3代表原子和晶胞都优化,6只优化晶胞。对于切片或二维材料、多变量不能用3
#Tips:复杂的结构优化过程,可以分步优化,即初始只优化离子(ISIF=2)→优化晶胞(ISIF=6)→优化离子和晶胞(ISIF=3)
NSW = 100 #最大离子步数,单点能计算,如果晶胞优化后进行静态计算,NSW需要设置为0
EDIFFG = -2E-02 #不写即默认,此时EDIFFG = EDIFF×10,即能量收敛,正数为能量收敛ev。负数表示力收敛,ev/埃,一般在-0.01-0.05间
#4态密度和能带相关
#NEDOS = 2000 #DOS点的个数,通常设置1000-3000
#EMIN
#EMAX #计算态密度的能量窗口
#LORBIT #总态密度投影,10:投影到s、p、d、f轨道.11:投影到s、px、py、pz.....轨道
#NBANDS #总能带数
#5磁性和加U以及偶极矫正
#ISPIN = 1 #1为默认值,表示不进行自旋极化计算。2表示需要进行自旋极化计算
#MAGMOM = 原子个数*磁矩 #如果原子的MAGMOM为负值,则写成原子数乘负的磁矩,如氧10*-2
#IVDW #范德华力计算方法
#LDA+U
#LDIPOL = .TRUE. #偶极矫正,Slab模型一般都需要加上这个参数
#IDIPOL = 3 #偶极矫正,Slab模型一般都需要加上这个参数
poscar
O2 Ti
1.0
3.7300000191 0.0000000000 0.0000000000
0.0000000000 3.7300000191 0.0000000000
0.0000000000 0.0000000000 9.3699998856
Ti O
4 8
Cartesian
0.000000000 0.000000000 0.000000000
1.865000010 1.865000010 4.684999943
0.000000000 1.865000010 2.342499971
1.865000010 0.000000000 7.027499914
0.000000000 0.000000000 1.874000005
1.865000010 1.865000010 6.558999808
0.000000000 1.865000010 4.216499837
1.865000010 0.000000000 8.901499780
1.865000010 0.000000000 5.153500049
0.000000000 1.865000010 0.468499966
1.865000010 1.865000010 2.811000077
0.000000000 0.000000000 7.496000020
KPOINTS
K-Spacing Value to Generate K-Mesh: 0.030
0
Gamma
8 8 8
0.0 0.0 0.0
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