A convergence problem with Al and Al alloys
Posted: Mon Dec 21, 2009 9:38 pm
Dear all,
I am doing a series tests on Al and Al alloys with VASP. I found that when I increase the cutoff energy above 400eV, it gives crazy results. When you look at a curve of a quantity on the dependence of the cutoff energy, above a certain cutoff, the curve is doing massive dynamic oscillation. It makes me really depressed and annoyed.
I have two questions:
(1) is it normal? or it is the feature of Al.
(2) what is the best quantity to look at to see if it is convergent or not? the ground state energy, lattice parameters, bulk moduli or the cohesive energy.
I will be very glad and grateful, if someone encountered such problem, solved it and is willing to share the successful story. !amazed
<span class='smallblacktext'>[ Edited ]</span>
I am doing a series tests on Al and Al alloys with VASP. I found that when I increase the cutoff energy above 400eV, it gives crazy results. When you look at a curve of a quantity on the dependence of the cutoff energy, above a certain cutoff, the curve is doing massive dynamic oscillation. It makes me really depressed and annoyed.
I have two questions:
(1) is it normal? or it is the feature of Al.
(2) what is the best quantity to look at to see if it is convergent or not? the ground state energy, lattice parameters, bulk moduli or the cohesive energy.
I will be very glad and grateful, if someone encountered such problem, solved it and is willing to share the successful story. !amazed
<span class='smallblacktext'>[ Edited ]</span>