convergence

[nrbsh]

Dear all

I have converged yambo variables for g0w0 and bse calculations for a bulk system.
Now I want to change my system from bulk to nano-structure
with the same structure and atoms.
In the bulk structure I have only 4 atoms in each unit cell but in my super lattice (for the nano-structure) I have 4*n atoms (n=1,2,..).

My question is about the dependence of the converged parameters in the new system and the bulk system.
Can I use the same NGsBlk?

For the polarization function bands (BndsRn), if the converged variables in the bulk system were a|b|;
should I use n*a|n*b| bands in the nano system?

What about other paramenters?

Many thanks,
Zara
Tehran University
Physics Department

[myrta gruning]

Dear Zara,

No, you cannot use the same NGsBlk if you expressed it in RL. This depends on the cell, so changing the cell, this number will change. If you used Ry this does not depend on the cell.
However in nanostructures you have confinement effects and less effective screening, so I would use the bulk values as an indication and repeat from there convergence calculations. Similarly for the number of bands.

Regards,
Myrta