UT theoretical chemistry code forum

Thank you so much!

Dear All,

I'm trying to install the most recent version of TST tools with VASP 6.2.1. At the step:
"To build the code, the VASP makefile needs to be changed. Find the variable SOURCE, which defines which objects will be built, and add the following objects before chain.o"

I'm unable to locate the ...

Hi Jeremie,

The small difference you found between different oxidation states has a fundamental reason. It is the so-called charge-self regulation mechanism. Essentially if you go from Ni3+ to Ni2+ anticipating a change of 1 in the bader charge, then this does not happen and most of the extra one ...

Thank you, Prof. Graeme!

I'm performing non-collinear calculations using VASP and was wondering if the Bader code can analyze the CHGCAR generated by such calculations. If this is not implemented yet, any guidance on how to implement it will be very appreciated.


Thank you!

Thank you for your help! It was indeed the electronic convergence that lead the high energy cutoff calculations to show this wild behavior. I started from scratch using cutoff 600 eV , EDIFF = 1E-08, and TIMESTEP=0.03. This calculation while is still running, seems to be ok.

I think you missed the POTIM parameter which is important to control the convergence. You can also tail the standard output file to check what went wrong. Here is a sample INCAR that worked for me using VASP4.6

TEST NEB
ISTART=0 ; ICHARG = 2
ISMEAR = 0 ; SIGMA =0.05
ENCUT= 450
IBRION=1 ; ISIF=2 ...

A related question, is ISYM=0 recommended for this type of calculations?

Thank you!

I have an issue with SSNB to study a martensitic phase transition in a metal oxide and any tips would be very appreciated.
In all cases I did linear interpolation between the first and final states. First I tried to do energy cutoff convergence on 5 intermediate images. The lower energy cuttoffs ...

It is a diffusive jump in bulk and hence there are three imaginary frequencies corresponding to translation. So in the initial state I obtain 3 imaginary frequencies and in the saddle there are 4 or 5 depending on POTIM.
I will try to follow your suggestion and see what happens when I repeat with ...

I tried to do a convergence study for the value of the pre-exponential for a diffusive jump as a function of the parameter POTIM. I varied POTIM from 0.001 to 0.012 with a step of 0.001. For all calculations: EDIFF = 1E-08, PREC=High. Out of 12 simulations only 4 with POTIM values: 0.002,0.003,0.011 ...

Thank you for your suggestions. I tend also to believe also that it is sort of trapping in an excited state.

In both NEB calculations, I used the same end points (Same POSCAR and OUTCAR). These end points correspond to the ground state which is in this case singlet (closed shell). While relaxing these two end points, both ISPIN=1 and ISPIN=2 converge to the singlet solution.
So, in fact what happened is ...

The ground state energy of a neutral oxygen vacancy in an oxide is closed shell singlet and hence the total magnetic moment is zero. I ran CI-NEB with ISPIN=1 to compute the migration barrier of this vacancy and obtained a value of 1.81 eV. Forces were converged to a value below 0.01 eV/A.
Out of ...

Thank you very much for your answer and explanation! That helps a lot!