How to set K numbers and band numbers in BSE@PBE0 calculation

[jasonhan0710]

Dear all,

I want to calculate the optical absorption spectrum in monolayer WSe2 by BSE calculation on top of PBE0 functional. However, The PBE0 functional requires too much memory if I use dense k points (25x25x1) and a large number of bands (total 200 bands), and the scf calculation stops at the ACE calculations with the error SIGNAL 9. Are there any ways to calculate the optical properties based on BSE@PBE0?

Best,
Jason

[Daniele Varsano]

Dear Jason,

yes it is possible, provided you have enough computational resources. The problem you are experiencing, which is probably a memory issue, should be posted in the Quantum Espresso mailing list.

My only suggestion is to start with a coarser k-grid mesh and increase it smoothly to have an idea of the size needed to achieve a reasonable convergence.

Best,
Daniele