why the energy difference is so large?
Posted: Mon Aug 15, 2016 9:14 am
I am calculating Adsorption of small moleculars like H, CO, H2O on higher index surfaces Co(311), but I get a very strange results. Take atomic H as the example, I choose several sites to find the most stable Adsorption configurations, but the calculated energy difference is very large (about 6eV). Specially, there are two different configurations, after the optimization, the atomic H both move to the same site and the energy should be the same as a result of the same configurations, but the energy difference is larger than 5eV. How does this happened? Is this because the INCAR Parameters?
SYSTEM = Co cell
ISTART = 0
ICHARG = 2
ENCUT = 400
ISPIN = 2
ISMEAR = 2
SIGMA = 0.20
LREAL = AUTO
PREC = NORMAL
EDIFFG = -0.05
EDIFF = 1E-4
ALGO = FAST
IDIPOL = 3
IBRION = 2
NSW = 400
POTIM = 0.2
#LORBIT = 11
#ISIF = 3
NELM = 100
NWRITE = 0
SYSTEM = Co cell
ISTART = 0
ICHARG = 2
ENCUT = 400
ISPIN = 2
ISMEAR = 2
SIGMA = 0.20
LREAL = AUTO
PREC = NORMAL
EDIFFG = -0.05
EDIFF = 1E-4
ALGO = FAST
IDIPOL = 3
IBRION = 2
NSW = 400
POTIM = 0.2
#LORBIT = 11
#ISIF = 3
NELM = 100
NWRITE = 0