ISMEAR - MP method versus tetrahedron
Posted: Fri Dec 21, 2012 5:29 pm
For a system with Pt on surface (transition metal ) with CeO2 (insulator) as substrate, what would you recommend ISMEAR > 0 or ISMEAR = -5?
I tried calculating with ISMEAR = 1 and SIGMA = 0.01 to get the entropy below 1 meV. What I need is very accurate energies and local potentials, so I was thinking of switching to ISMEAR = -5, but with ISMEAR=1, I notice a great deal of relaxation which basically means that I cannot compromise on the force calculations. I am not worried so much about the computational cost (not resorting to hybrid calculations though), but what would you suggest if i wanted both accurate forces and accurate energies ?
I tried calculating with ISMEAR = 1 and SIGMA = 0.01 to get the entropy below 1 meV. What I need is very accurate energies and local potentials, so I was thinking of switching to ISMEAR = -5, but with ISMEAR=1, I notice a great deal of relaxation which basically means that I cannot compromise on the force calculations. I am not worried so much about the computational cost (not resorting to hybrid calculations though), but what would you suggest if i wanted both accurate forces and accurate energies ?