UT theoretical chemistry code forum

[quote=graeme post_id=8943 time=1493222352 user_id=2] Ah yes, my apologies, I understand now that you have a number of frozen atoms and those high forces are on the frozen atoms so they do not contribute to the convergence criterion. Try making smaller displacements along your reaction coordinate. T...

Dear Graeme, What you are recommending is exactly what I have tried to do. The nebmake.pl generated 01 02 03, and the position of migrating atom in 02 was in the center of the cell due to the equivalence between 00/POSCAR and 04/POSCAR by symmetry. I then manually introduced displacement to the migr...

Dear Graeme, I switched to CG optimizer and continued the neb calculation. The calculation converged and the forces are OK now (Please see the attachment). I still tested the energies as I did in test-force/. The variation trend of energy due to displacement of migrating atom is the same, i.e., it i...

[quote=graeme post_id=8939 time=1493171071 user_id=2] Double check the geometry in your test; the structure from your energy test is different from the CONTCAR in many degrees of freedom and it has a high force. [/quote] Dear Graeme, I apologize for not checking it carefully before bothering you for...

[quote=graeme post_id=8937 time=1493151469 user_id=2] The configuration in OUTCAR.0.0 does not appear to be the same and in the 02/CONTCAR file, which I assume is your saddle point. There are also relatively high forces listed in OUTCAR.0.0. [/quote] Dear Graeme, Thank you very much for your quick r...

[quote=graeme post_id=8900 time=1491923459 user_id=2] You need to turn symmetry off (ISYM=0). The problem is that your 02 image detected symmetry and then it was broken during relaxation. With the geometry not having the symmetry of the wavefunction leads to the non-physical energies that you are se...

Thank you very much for your help. I will try it again.

H

Dear Graeme, Thank you very much for the reply. Please find the file I attached. Just two notes here. Prob. 1 lies in the directory 02/test-force with the converged CONTCAR based on one-image cNEB calculation. The rest files correspond to Prob. 2. Please let me know if any more information is needed...

Dear vtst community, I am using vtsttools to investigate the migration of oxygen in cubic ZrO2 but just met some problems. I think I need your kind help. There are basically two: 1. I just used one image to find out the saddle point and it converges well. The barrier is about 0.4 eV. But when I trie...