IBRION=3 bulk optimization: Difference between revisions

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To choose a proper value for the POTIM in case of a IBRION=3 bulk optimization, you first need to perform a frequency calculation, setting in the INCAR file
To choose a proper value for the POTIM in case of a IBRION=3 bulk optimization
 
1. You first need to perform a frequency calculation, setting in the INCAR file
        
        
  frequencies:
  frequencies:
Line 7: Line 9:
   NFREE  =  2    #  
   NFREE  =  2    #  


When this calculation converge you need to
'''PLEASE NOTE''': just the degrees of freedom of the investigated bonds must be relaxed.
 
2. When this calculation converge, based on the POSCAR and OUTCAR of the frequencies calculation, you need to execute
 
getdimer POSCAR OUTCAR POSCAR
 
which will generate a ''eigenvectors.dat'' file, presenting the following format
 
Info:            0
Eigenvalues
  -31.491683333336404      -29.378686935390292      -14.997850470930652      -9.6057143126896563      -5.4292953596452289      -1.6881155935524064      -1.3100285123688000      -1.1825456664410310      -0.59115181564548613
 
3.

Revision as of 11:09, 23 October 2018

To choose a proper value for the POTIM in case of a IBRION=3 bulk optimization

1. You first need to perform a frequency calculation, setting in the INCAR file

frequencies:
 IBRION =   5     #     
 EDIFF  =  1E-7   # 
 POTIM  =   0.010 #                  
 NFREE  =   2     # 

PLEASE NOTE: just the degrees of freedom of the investigated bonds must be relaxed.

2. When this calculation converge, based on the POSCAR and OUTCAR of the frequencies calculation, you need to execute

getdimer POSCAR OUTCAR POSCAR

which will generate a eigenvectors.dat file, presenting the following format

Info:            0
Eigenvalues
 -31.491683333336404       -29.378686935390292       -14.997850470930652       -9.6057143126896563       -5.4292953596452289       -1.6881155935524064       -1.3100285123688000       -1.1825456664410310      -0.59115181564548613 

3.