UT theoretical chemistry code forum

Dear graeme, I highly appreciate for your comments. I learned much from your comments and finally obtain the reasonable energy profile. Thanks again!

Deal all,
I obtained an abnormal and negative energy profile of the phase transition from beta-Ti to alpha-Ti. In general, there is no energy barrier for this phases transitions. However, the flat and descend energy profile may be changed when some additive elements are added.

I want to obtain the ...

Dear graeme, very thanks for your help! I also obtained the nice symmetric barrier profile of Zr migration mediated by Al-cacancy with IALGO=38. The non-symmetric profile is indeedly related to the electronic converging problem of Zr. Thanks again.

Dear graeme, thanks for you kind reply!
As your suggestions, I set ISYM=0 and used the following low precision setting: 2x2x2 k-point mesh, PREC=normal, ENCUT=250 eV and EDIFFG=-0.1. However, the CI-NEB profile is still non-symmetric and looks more strange, as the following figure illustrated ...

[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 ...