UT theoretical chemistry code forum

Yes, I got the smooth curves when I use the enthalpies. Please let me know, when you update the vstpscripts. Thank you.

Did you use the enthalpies from VASP in your calculation using TSASE? In VTSTscripts, the nebbarrier.pl reads the free energies while not enthalpies of the images. Do you think that it is a reason that the highest energy image can not sit on the saddle point after spline under high pressure? Under ...

I used DFPT in VASP to calculate the phonons at gama point. I got two imaginary frequency. One is 190cm-1, the other is 301 cm-1. I don't think there are problems in my calculation of phonons. I have done the neb calculation on some different systems. Under 10GPa, for all the cases, I can get good ...

There are image translating in my previous calculation. I recalculated them again by fix one atom in each image. Now, there are no tranlating. However, there is still no image sitting on the saddle point. I calculated the phonon of the highest energy image and found there are two negtive frequency ...

No matter what I do, I can not get a smooth mep curve where the highest image sit on the saddle point under 30GPa. Under 10GPa, I always get curves with images sit on the saddle points. It seems that under high pressure, the climb neb method not work well. I'll calculate the frequency to check ...

10GPa, nebss.dat
0 0.000000 0.000000 0.000000 0
1 0.102707 0.004305 -0.014135 1
2 0.207701 0.020212 -0.109129 2
3 0.314128 0.063382 -0.349505 3
4 0.416795 0.127964 -0.517634 4
5 0.518140 0.174005 0.000045 5
6 0.612178 0.138514 0.926411 6
7 0.706679 0.056008 0.751208 7
8 0.801659 0.042941 -0 ...

I'm studying the phase transition using ss-NEB from graphite to a carbon three-dimensional structure. I did it under different pressure. I found that under 10GPa, the mep curve is excellent where the line is smooth and the highest-energy image sit on the saddle point. However, under 30GPa, the ...

Another question. Must I use IOPT=3 and IBRION=3 in solid state NEB calculation. Can I use other optimization method?
The normal fixed-cell NEB calculation using IBRION=2 can get perfect mep curve.

In my another job, there is no translation between images. However, I still get a mep curve where the highest energy image does not sit on the saddle point. I thought may be I select two few images (5), so I increase the number of images to 8. However, I get almost the same curve. The same cases are ...

Yes, when I watched the movie, I found the first three images really just translate. I'll try to fix one atom. The question is whether I sould fix that atom in all images or just tat in the first and last images?

When I use 5 images, the jobs run well. After the calculation finish, I use the nebresult.pl script to get the barrier. I opened the CI-NEB by setting the 'LCLIMB = .TURE ." However, I found that no image sit on the saddle point. Is that because I used small number of images or any other reasons ...

I compared every file in vtstcode-2.04a downloaded before and vtstcode-2.04b. I found version of dimer.F is v1.36 in vtstcode-2.04a while it is v1.33 in vtstcode-2.04b. So, I think you just upload an older version of vtstcode. In this package, it does not contain ssNEB.

yes, I have changed main.F according the instruction. In chain.F file, the subroutine chain_force is : SUBROUTINE chain_force(nions,posion,toten,force,a,b,iu6). It should contain a 'stress' variable.
The sentence in main.F is changed into
CALL CHAIN_FORCE(T_INFO%NIONS,DYN%POSION,TOTEN,TIFOR ...

The new version failed to compile with error. The subroutine of chain_force dosn't contain 'stress' varable. Please update a correct one.

mpif90 -FR -lowercase -assume byterecl -heap-arrays -FR -O0 -c main.f90
main.f90(2555): error #6784: The number of actual arguments cannot be greater than the ...

The VTSTCODE on the download website is updated in August,2011. Do you have a new version? Where can I download it?