In data 03 giugno 2009 alle ore 11:35:06, chu-chun fu <chuchun.fu at cea.fr> ha scritto:
> Thank you for your response. Maybe I was not clear enough in my previous > email. My question is not to give occupation Z to atom X, but local M > (magnetization) to atom X. My question actually concerns the 'atomic' > constrained magnetization option already implemented in PWscf (in > particular version 4.0.3) by adding a 'penalty functional' as can be > seen in the SUBROUTINE add_bfield, Well, yes I mistaken your question a bit, yet that's what constrained DFT is about. > Just wonder if we can only constrain the local magnetization of only one > species instead of all the atoms to respective values as fixed in the > input. You cannot, but you can assign a different (formally) specie to each atom doing something like this: ATOMIC_SPECIES Pd_1 106.40 Pd.pbe-paw_kj.UPF Pd_2 106.40 Pd.pbe-paw_kj.UPF Pd_3 106.40 Pd.pbe-paw_kj.UPF ATOMIC_POSITIONS Pd_1 0.000000 0.000000 0.000000 Pd_2 0.250000 -0.144340 0.408250 Pd_3 0.500000 -0.288680 0.816490 the species will be equivalent in practice, but distinct from the code point of view, hence you can assign different constraints to them. It has to be done this way because of how the symmetry analysis works: atoms of the same specie can in principle occupy equivalent positions, in which case it would make no sense to assign different properties to each of them. best regards -- Lorenzo Paulatto SISSA & DEMOCRITOS (Trieste) phone: +39 040 3787 511 skype: paulatz www: http://people.sissa.it/~paulatto/ *** save italian brains *** http://saveitalianbrains.wordpress.com/
