Dear Sumegha,

It is pretty easy to perform the calculation of the frequencies for the dissociation of CO on a cluster. You have to use Selective Dynamics on your POSCAR and fix the coordinates from your cluster with the labels F F F, while the coordinates of the CO have to use T T T. You have to set IBRION = 5, and remove NPAR from your incarceration, also you can remove NSW = 1.

Dear Sinhue,

Thanks for the answer.

Now, Do I have to mannually put F and T in front of coordinates of the atoms as I fixed them in Materials studio and exported to VESTA to make POSCAR but did not show ant F or T tags for fixed and free atoms. So I put them manually as follows(Sorry if it is too dumb):

Ni C O

1.00000000000000

25.0000000000000000 0.0000000000000000 0.0000000000000000

0.0000000000000000 25.0000000000000000 0.0000000000000000

0.0000000000000000 0.0000000000000000 25.0000000000000000

Ni C O

55 1 1

Selective

Direct

0.5543349186112012 0.4958231238930741 0.5301060465342647 F F F

0.5280401580022183 0.5777788880708620 0.4776622708842411 F F F

0.4768980452852018 0.5509249546800127 0.5602666366484091 F F F

0.4167207916984794 0.3677553865534811 0.3987422954482114 F F

.

.

..

this goes on till all the atoms are there. While running the calculation I got error after 15 steps of 1st iteration. "ERROR FEXCF: supplied exchange-correlation table

is too small, maximal index : 4381"

And this might be due to the geometry. Please suggest me what to do.

Thanks a lot.

I had never seen this error, but this problem should be resolved in some way. Note that now you are not performing the neb calculation, so, I will suggest the next INCAR,

GGA = RP

#NPAR = 60

LREAL = AUTO

EDIFF = 0.000001

#EDIFFG = -0.02

ALGO = normal

PREC = normal

ENCUT = 400.0

ISMEAR = 0

SIGMA = 0.10

ISPIN = 2

ISIF = 2

IBRION = 5

#NFREE = 2

#ISYM = 0

#POTIM = 0.01

#IOPT = 3

NELMIN = 3

LWAVE = .FALSE.

LCHARG = .FALSE.

ISTART = 0

ICHARG = 2

#NSW = 1

May be latter you could try to include NFREE = 4.

Please let me know if it works.

Regards

Dear Sinhue,

Thank you for the answer. I am still having that error.

I have one doubt that the way I am making POSCAR is not correct. I put F and T manually in front of the coordinates , is this how it should be or there is another way to make POSCAR with F and T tags for selective dynamics. Because If I freeze the atoms in Materials Studio they appear without F and T tags.

Thanks

Regards,

Dear Sumegha, I am not using Materials Studio, so, I don't know how it works. The calculations of frequencies with VASP requires to specify which atoms are free to move and those that are frozen. I use to perform such calculations with surfaces or 2D materials like graphene and I had never a problem like that.

So you specified them manually by editing POSCAR?

Also I am working on graphene as well. Please provide your email address I might have few questions regarding that.

Thanks

[email protected]

Dear Sinhué ,

I got the following from OUTCAR. I could not make freq.dat due to some error. And I think none of them is negative frequency. This was supposed to be transition state on the basis of NEB calc. Please suggest something.

1 f = 18.822118 THz 118.262854 2PiTHz 627.838251 cm-1 77.842050 meV

2 f = 15.378660 THz 96.626970 2PiTHz 512.976860 cm-1 63.601048 meV

3 f = 12.482416 THz 78.429334 2PiTHz 416.368572 cm-1 51.623142 meV

4 f = 11.740426 THz 73.767272 2PiTHz 391.618445 cm-1 48.554516 meV

5 f = 8.619513 THz 54.157996 2PiTHz 287.515990 cm-1 35.647452 meV

6 f = 7.171923 THz 45.062520 2PiTHz 239.229587 cm-1 29.660699 meV

you have to plot the eigenvectors in conjunction with the coordinates of the atoms in order to observe the stretching frequency. If you wish send the CONTCAR and the OUTCAR to my e-mail and I will show you how to do that.

I have sent you an email.