ABINIT Discussion Forums

Dear all,
I saw a sentence from the key word "optcell' in abinit help files:
"It is STRONGLY suggested first to optimize the ionic positions without cell shape and size optimization (optcell=0), then start the cell shape and size optimization from the cell with relaxed ionic positions."
Then, my question is, whether the atom positon need relaxation at the second step, i.e. optcell=?
Thanks a lot.
yours wjj

Hello,

What is advised is to make your relaxation in two steps :

1) ionmov 2 (or other but different from 0) and optcell 0
2) ionmov 2 (or other but different from 0) and optcell 2, using the atomic positions from step 1) as initial ones

David

Thanks a lot. I now hnow how to make a relaxation.