Hello

Unless you are using supercluster computing or some very sophisticated computation server your k-pts are much too high!

For systems consisting of even small number of atoms,  when your cell is really small the kpoints mesh should look like 15x15x15 or similar. Therefore I'm asking: do you really need such big mesh of k-pts?

If your answer is YES and  this error is not related to your RAM size then you will need to make some changes in QE source code (look in Modules/parameters.f90) where you can find the max K-pts number.

Regards,

K. Gruszka

hi,Konrad

i have do a 2D period system about 10 atoms before ,but i find the k points must be about 60 60 1 that it can just converge ,so i have do the k mesh from 10 10 10 to 100 100 100, as you say above when i select the initial k points for the converging test, how should i set ?is there any difference between the period system and the molecular ?

thanx

Yes, there is some difference in periodic vs non periodic systems (you have to apply a vacuum to separate periodic images when you want to calculate i.e. molecule).

For 2D periodic systems the k-mesh in direction where your structure is thinnest can be set to 1.  So you will have to change only "AA" in mesh  AAxAAx1. 

On the other hand 60x60x1 is also very big mesh. Meybe you should check ecutwfc and ecutrho? can you show your input file?

i am sorry the 2D system has been done some time ago on another cluster, so i cant find it ,but i remember the deguass is not small enough ,it maybe 0.02 or 0.01, so the k

points should be big enough to calculate precisely. 

thank u for answering me so clearly, and sorry for taking your time .

thanks.

Lee Cheedge