Nudged Elastic Band on chemical reaction

Queries about input and output files, running specific calculations, etc.


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yoshiyuki
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Nudged Elastic Band on chemical reaction

#1 Post by yoshiyuki » Wed May 21, 2008 6:40 am

I performed NEB method to calculate the activation barrier of the following addition reacton.
H2C=CH2 + HCl --> trans-CH3CH2Cl
The eclipsed-CH3CH2Cl is a local minimum on this system, and its total energy is 0.15eV higher than that of trans.
The structure of image 1, 01/CONTCAR, changed depending on the 01/POSCAR. That is, eclipsed-CH3CH2Cl or trans-CH3CH2Cl is obtained as 01/CONTCAR.
Is it possible to apply the NEB method to the chemical reaction?

INCAR file:
System = molecules
IDIPOLE = 4
IMAGES = 1
SPRING = -5
IBRION = 1
NFREE = 2
ISPIN = 2
MAGMOM = 2 2 1 1 1 1 1 1
NSW = 1000
ENCUT = 500.00
PREC = Accurate

KPOINTS file:
1x1x1
0
Monkhorst
1 1 1
0 0 0

00/POSCAR file:
CH2CH2_HCl
15.00
1.00 0.00 0.00
0.00 1.00 0.00
0.00 0.00 1.00
2 5 1
Selective dynamics
Direct
0.538 0.538 0.965 F F F
0.477 0.477 0.946 F F F
0.521 0.608 0.975 F F F
0.608 0.521 0.975 F F F
0.407 0.495 0.938 F F F
0.495 0.407 0.938 F F F
0.484 0.484 0.078 F F F
0.463 0.463 0.161 F F F

01/POSCAR file:
TRANSITION_CH3CH2Cl
15.00
1.00 0.00 0.00
0.00 1.00 0.00
0.00 0.00 1.00
2 5 1
Selective dynamics
Direct
0.536 0.536 0.000 T T T
0.465 0.465 0.990 T T T
0.536 0.534 0.080 T T T
0.594 0.510 0.035 T T T
0.406 0.490 0.954 T T T
0.490 0.406 0.954 T T T
0.557 0.557 0.932 T T T
0.466 0.467 0.105 T T T

02/POSCAR file:
TRANS_CH3CH2Cl
15.00
1.00 0.00 0.00
0.00 1.00 0.00
0.00 0.00 1.00
2 5 1
Selective dynamics
Direct
0.536 0.536 0.000 F F F
0.465 0.465 0.990 F F F
0.510 0.594 0.035 F F F
0.594 0.510 0.035 F F F
0.406 0.490 0.954 F F F
0.490 0.406 0.954 F F F
0.557 0.557 0.932 F F F
0.427 0.427 0.095 F F F
Last edited by yoshiyuki on Wed May 21, 2008 6:40 am, edited 1 time in total.

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Nudged Elastic Band on chemical reaction

#2 Post by admin » Wed May 21, 2008 6:40 pm

if you kow that the eclipsed-CH3CH2Cl configuration is a local minimum, I would split the NEB into 2 parts to safely obtain both transition barriers:
1) H2C=CH2 + HCl --> eclipsed-CH3CH2Cl
2) eclipsed-CH3CH2Cl --> trans-CH3CH2Cl
and finally combine 1 and 2 to capture the complete reaction path
Last edited by admin on Wed May 21, 2008 6:40 pm, edited 1 time in total.

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