常用INCAR文件例子

常用INCAR文件例子

1. Static calculations

Just remove the WAVECAR file and start from scratch, no parameters must be specified in the INCAR file. The defaults for

ISTART = 0 # startjob: no WAVECAR file

ICHARG = 2 # charge: from atoms

INIWAV = 1 # random initialization for wf.

NELM = 40 # maximum of 40 electronic steps

NELMIN = 2 # minimum of two steps

NELMDL = -5 # no update of charge for 3 steps

EDIFF = 10E-4 # accuracy for electronic minimization

2. Continuation of a calculation

In some cases it makes sense to start from an old WAVECAR file (for instance to continue relaxation or to continue with an increased energy cutoff ENCUT). In this case just keep the WAVECAR file and start VASP. Again, an empty INCAR file will suffice.

ISTART = 1 # continue from WAVECAR file

ICHARG = 0 # charge from wavefunctions

NELM = 40 # maximum of 40 electronic steps

NELMIN = 2 # minimum of two steps

NELMDL = 0 # immediately update charge

You can set ICHARG=1 by hand if an old CHGCAR file exists. If the charge sloshing is significant this will save a few steps, compared to the default setting. To continue relaxation from a previous run copy the CONTCAR file to POSCAR.

3. Recommended minimum setup

Although the previous calculations can be performed using an empty INCAR file it is recommended to specify a few parameter always manually

PREC = Normal # precision normal

ENCUT = 300 # cutoff used throughout all calculations

LREAL = .FALSE. or Auto # real space projection yes / no

ISMEAR = 0 or 1 or -5 # method to determine partial occupancies

These four parameters should be present in all calculations. They completely control the technical accuracy of the calculations in particular the basis sets (ENCUT), and wether the real space projection scheme is used or not. Total energies of two calculations should be only compared and subtracted, if the first three parameters are set identically in both calculations.

Ideally the parameter ISMEAR should be also identical throughout all calculations (but this might be difficult in some cases).

4. Efficient relaxation from an unreasonable starting guess

If you want to do an efficient relaxation from a configuration that is not close to the minimum, set the following values in the INCAR file (for briefness the recommended setup is lacking

NELMIN = 5 # do a minimum of four electronic steps

EDIFF = 1E-2 # low accuracy

EDIFFG = -0.3 # accuracy of ions not too high

NSW = 10 # 10 ionic steps in ions

IBRION = 2 # use CG algorithm

This way only low accuracy will be required in the first few steps, but since a minimum of 5 electronic steps is done the accuracy of the calculated electronic groundstate will gradually improve. If you are a slightly advanced user you can also use the damped MD algorithm, which is usually more efficient than the CG one:

IBRION = 1 ; SMASS = 0.4 # damped MD

POTIM = 0.4 # time step needs to chosen with care

In this case, a too large POTIM will result in divergence.

5. Efficient relaxation from a pre-converged starting guess

Close to a local minimum the variable-metric (RMM-DIIS algorithm) is most efficient. INCAR file (for briefness the recommended setup is lacking):

NELMIN = 8 # do a minimum of ten electronic steps

EDIFF = 1E-5 # high accuracy for electronic groundstate

EDIFFG = -0.01 # small tolerance for ions

NSW = 20 # 20 ionic steps should do

MAXMIX = 80 # keep dielectric function between ionic movements

IBRION = 1 # use RMM-DIIS algorithm for ions

NFREE = 10 # estimated degrees of freedom of the system

Now very accurate forces are required (EDIFF is small). In addition a minimum of eight electronic steps is done between each ionic updated, so that the electronic ground state is always calculated with very high accuracy. NELMIN=8 is only required for systems with extreme charge sloshing which are very hard to converge electronically. For most systems values between NELMIN=4 and NELMIN=6 are sufficient.

6. Molecular dynamics

Please see section 9.7.

7. Making the calculations faster

Use the following lines in the INCAR file to improve the efficiency of VASP for large systems: ALGO = Fast # RMM-DIIS algorithm for electrons

LREAL = A # evaluate projection operators in real space

NSIM = 4 # blocked algorithm update, four bands at a time

INCAR中常用关键词：

注释行：SYSTEM

初始化参数-电荷和波函数：ISTART, ICHARG, INIWAY

电子结构优化：

平面波截断动能和缀加电荷截断值：ENCUT, ENAUG

电子优化方法：ALGO, IALGO, LDIAG

自恰迭代步数和收敛标准：NELM, NELMIN, NELMDL, EDIFF 原子结构优化：

位置移动方法、步长和步数：IBRION, NFREE, POTIM, NSW

分子动力学：SMASS, TEBEG, TEEND, POMASS, NBLOCK, KBLOCK, PSTRESS 收敛标准：EDIFFG

态密度计算：

smearing方法：ISMEAR, SIGMA

能量范围：EMIN, EMAX, NEDOS

分波态密度：RWIGS, LORBIT

其他：

计算精度：PREC

磁性计算：ISPIN, MAGMOM, NUPDOWN

交换关联函数：GGA, VOSKOWN

结构优化参数：ISIF

等等

Smearing方法的选择：

总能/DOS计算：

k点数目大于4：布洛赫修正的四面体方法，ISMEAR=-5

k点数目小于4：Gaussian方法，ISMEAR=0，设置Sigma

计算力或结构优化：

半导体和绝缘体：同上

金属：M-P方法，N=1或2，设置Sigma

能带计算：ISMEAR和SIGMA采用默认值

不管何种体系、计算什么性质采用ISMEAR=0，并选择合适的SIGMA值都能得到合理的结果

线性四面体方法和布洛赫修正的线性四面体方法一定要检验能量收敛情况

赝势选择：

赝势分类原则如下，

根据方法不同有Ultra-soft赝势（USPP）和增广平面波赝势（PAW）

根据交换关联函数不同有LDA和GGA（又可以再分为PW91和PBE）

根据半芯态处理有X，X_sv和X_pv

根据ENMAX的不同有X，X_s和X_h

计算磁性材料，所计算体系含有碱金属、碱土金属、周期表左边的3d过渡元素、镧系

和锕系元素时推荐采用PAW势。下表列出采用何种PAW以及ENCUT值至少取多少。

B_h 700 B 318 B_s 250C_h 700

C 400

C_s 273

N_h 700

N 400

N_s 250

O_h 700

O 400

O_s 250

F_h 700

F 400

F_s 250

Al 240 Al_h 295

Si 245

Si_h 380

P 270

P_h 390

S 280

S_h 402

Cl 280

Cl_h 409

Ga 134 Ga_d 282 Ga_h 404

Ge 173

Ge_d 287

Ge_h 410

As 208Se 211Br 216

In 95 In_d 239

Sn 103

Sn_d 241

Sb 172Te 174I 175

Tl 95 Tl_d 239

Pb 98

Pb_d 237

Bi 105

Bi_d 242

H 250

H_h 700

Li 140

Li_sv 271

Be 300

Be_sv 308

Na 81

Na_pv 300

Na_sv 700

Mg 210

Mg_pv 265

Sc_sv 222Ti 178

Ti_pv 222

V 192

V_pv 263

Cr 227

Cr_pv 265

Mn 269

Mn_pv 269

Y_sv 211Zr_sv 229Nb_pv 207Mo 224

Mo_pv 224

Tc 228 Tc_pv 228

Hf 220 Hf_pv 220

Ta 223

Ta_pv 223

W 223

W_pv 223

Re 226

Re_pv 226

Fe 267 Fe_pv 293Co 267Ni 269

Ni_pv 367

Cu 273

Cu_pv 368

Zn 276

Ru 213 Ru_pv 230

Rh 228

Rh_pv 271

Pd 250

Pd_pv 350

Ag 249Cd 274

Os 228

Os_pv 228

Ir 210Pt 230Au 229Hg 233

Ce 300Pr 252Nd 253Pm 258Sm 225Eu 249Gd 256

Tm 257Yb 291Lu 255

La 219 La_s 136

Ac 169

Ac_s 119

Th 247

Th_s 169

Pa 252

Pa_s 193

U 252

U_s 209

Np 254

Np_s 210

Pu 254

Pu_s 211

X_d表示d电子作为半芯态来处理。为了得到较高的计算精度，一般推荐采用X_d赝势。X_h表示该势比较硬，截断动能要取很大。它们一般是用含有这类原子的氧化物的计算中。Si_h一般用在含Si的沸石材料中。

X_sv表示把s电子作为半芯态处理，X_pv考虑把p电子作为半芯态来处理。这些元素

一般很难赝化，特别是与电负性很强的元素（如F）结合时计算误差比较大。选择使用

X_pv还是X，主要与计算精度有关：

3d元素，一般选用X_pv，但是X的赝势也是能给出比较合理的结果。

4d元素，最有问题，强烈推荐用X_sv和X_pv的赝势。

5d元素，由于5p电子局域化很强，从Hf元素开始可以选用X的赝势。推荐不同的赝势进行测试。