detect no convergence and kill

[esp]

YEs but the problem was that only nanoribbon adds vacuum in more than 1 dimension, and in the case of my script where i am putting together different ribbons and then passivating, the nanosheet still only had vacuum on top and bottom, and my hydrogen atoms were sticking outside the box .... i had the same vacuum parameter on both but only with nanoribbon did it add vacuum in 3d ... which i needed

[Anders Blom]

This is actually related to our previous discussions about "periodicity". The nanosheet is relevant if you want a whole graphene sheet, but if you indeed want the 1D system, it is a ribbon.

Thus, the primary reason for your bad convergence was probably a mismatch between k-points and geometry - the structure was periodic but you had only 1 k-point. Esp. for graphene this is a very bad choice.

[esp]

I see thank you