[Pw_forum] convergence NOT achieved after 100 iterations: stopping

[Paolo Giannozzi]

On Fri, 2012-04-27 at 09:20 +0800, Cao TF wrote:

> The problem is that when I let hydrogen atoms adsorb on the N atoms,
> the calculation is hard to converge.

you should start with a smaller, more manageable calculation,
experiment a bit with parameters. It is hard to say anything
for a relatively large system without investing a sizable
amount of time and computer resources.

> nosym = .TRUE. , 

you shouldn't use this unless you have a good reason 

> degauss = 0.005 , 

it looks small to me

> nspin = 2 , 

you have 2 H atoms, so the system might be unpolarized.
Try no spin first

> starting_magnetization(1) = 0.5 , 

in any event, start with magnetization on H atoms, not on N or B

> diagonalization = 'cg' , 

you shouldn't use this unless you have a good reason 

P,
-- 
Paolo Giannozzi, IOM-Democritos and University of Udine, Italy