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tiger11212

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应助: 0 (幼儿园)
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帖子: 32
在线: 505.6小时
虫号: 232030
注册: 2006-03-28
性别: GG
专业: 分子模拟

[求助] 孤立NH3分子的DOS计算与文献不符

我首先按如下进行:
1 优化NH3,INCAR如下:
general:
System = NH3
PREC=Accurate
ISTART = 0 ; ICHARG = 2 ;
EDIFF = 1E-5 ;
ENCUT  =  400
ISMEAR = 1; SIGMA = 0.2
Ion Relaxation:
EDIFFG = -0.015
NSW = 500
IBRION =  2
POTIM = 0.2
NPAR = 2
K点在tao点
得到的计算结果和文献非常吻合.
2 静态计算, 将1步的CONTCAR 复制为POSCAR, INCAR如下:
System =NH3
ISTART = 0 ; ICHARG = 2
EDIFF = 1E-5 ;
ENCUT  = 400
EDIFFG = -0.015
IBRION = -1
NSW = 0
PREC = Accurate
此处我没有设置用了隐含的ISMEAR及sigma值等一些参数
3 计算DOS, 并且改变K点为 5 * 5 * 5 INCAR如下:
System =NH3
ISTART = 1 ; ICHARG = 11
ISMEAR = -5;
LORBIT = 11
EDIFF = 1E-5 ;
ENCUT  = 400
EDIFFG = -0.015
IBRION = -1
NSW = 0
PREC = Accurate
然后用split_dos分解得到总态密度DOS0,作图,发现,与文献相差太大了,文献有三个尖锐的峰,而我的都在一起,怎么回事?
另外,这是我的POSCAR:
NH3
1.00000000000000
15.0000000000000000 0.0000000000000000 0.0000000000000000
   0.0000000000000000 15.0000000000000000 0.0000000000000000
   0.0000000000000000 0.0000000000000000 15.0000000000000000
N H
1 3
Selective dynamics
Direct
  0.5229799999999969  0.4556699999999978  0.4820899999999995 F F F
  0.4747572401218676  0.4089732894885714  0.4943562314884602 T T T
  0.5828934127766203  0.4248546175374699  0.4929506476151957 T T T
  0.5166913251309211  0.5031757768430012  0.5306787459577365 T T T

  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00

谢谢了

Graph1.jpg

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