non-symmetric CI-NEB profile
Posted: Tue Feb 18, 2014 12:08 pm
[attachment=0]ci-neb.jpg[/attachment]Dear graeme and others:
I want to obtain the migration energy of Zr mediated by Al-vacancy in Al matrix with vasp5.3 and vtst 3.0c. However, the CI-NEB profile looks strange to me: the migration barrier of Zr is very high and the CI-NEB profile is non-symmetric. In my opinion, the CI-NEB profile should be symmetric since the local enviroment of Zr is the same befor and after its migration. One of its CI-NEB migration profile look like:
0 0.000000 0.000000 0.000000 0
1 0.567843 0.439777 -0.649155 1
2 1.135446 0.909418 -0.937834 2
3 1.702760 2.624547 -0.001909 3
4 2.270045 1.746428 0.936656 4
5 2.838103 0.700414 0.644985 5
6 3.406742 -0.000274 0.000000 6
[attachment=0]ci-neb.jpg[/attachment]
The 64-atom fcc supercell was used in my calculaitons. The problem still exists even I enlarge the superll to 108-atom or use vtst 3.0d. The whole files were packed and attached.
Any comments are highly appreciated!
Thanks in advanced!
randome
I want to obtain the migration energy of Zr mediated by Al-vacancy in Al matrix with vasp5.3 and vtst 3.0c. However, the CI-NEB profile looks strange to me: the migration barrier of Zr is very high and the CI-NEB profile is non-symmetric. In my opinion, the CI-NEB profile should be symmetric since the local enviroment of Zr is the same befor and after its migration. One of its CI-NEB migration profile look like:
0 0.000000 0.000000 0.000000 0
1 0.567843 0.439777 -0.649155 1
2 1.135446 0.909418 -0.937834 2
3 1.702760 2.624547 -0.001909 3
4 2.270045 1.746428 0.936656 4
5 2.838103 0.700414 0.644985 5
6 3.406742 -0.000274 0.000000 6
[attachment=0]ci-neb.jpg[/attachment]
The 64-atom fcc supercell was used in my calculaitons. The problem still exists even I enlarge the superll to 108-atom or use vtst 3.0d. The whole files were packed and attached.
Any comments are highly appreciated!
Thanks in advanced!
randome