Re: [SIESTA-L] Problem FixSpin

2007-11-30 Thread apostnik
> Hi Andrei, > > I understand the system could converge to metastable states, and of course > Eliseo has the right to expect that the system could converge to a given > one. However, what I understood from Eliseo's message is that he expected > the system to converge to a state in which the individ

Re: [SIESTA-L] Problem FixSpin

2007-11-30 Thread Marcos Verissimo Alves
Hi Andrei, I understand the system could converge to metastable states, and of course Eliseo has the right to expect that the system could converge to a given one. However, what I understood from Eliseo's message is that he expected the system to converge to a state in which the individual atoms h

Re: [SIESTA-L] Problem FixSpin

2007-11-28 Thread Andrei Postnikov
Dear Marcos, the systems Eliseo is working on are molecular magnets, they usually have well localized spins on 3d ions and can be brought to self-consistency in a number of different magnetic configurations. Even if (usually) there is a certain (single-determinant) ground-state magnetic configura

Re: [SIESTA-L] Problem FixSpin

2007-11-28 Thread Vasilii Artyukhov
FixSpin only fixes the total magnetization, making SIESTA very the Fermi levels for up and down spins so that the net spin population will be what you've specified in the parameter. This has nothing to do with the populations on individual atoms. Clearly, trying to impose a fixed spin on each atom

Re: [SIESTA-L] Problem FixSpin

2007-11-28 Thread Andrei Postnikov
Dear Eliseo, with respect to your problem of initializing different spin configurations, I can offer two comments: 1. When you start from scratch, I am not sure how exactly the initial spin splitting is constructed; I also had sometimes an impression that the resulting splitting (in the 1st iterat

Re: [SIESTA-L] Problem FixSpin

2007-11-28 Thread Marcos Verissimo Alves
Eliseo, The numbers you are showing for the spins are extracted from some integration over the densities, or those are the mulliken charges on the system? I will suppose that those are the numbers that come out after one or more complete self-consistency cycles; if it is so, it means that your sys

[SIESTA-L] Problem FixSpin

2007-11-28 Thread Eliseo Ruiz
Dear Colleagues, I am calculating a periodic system with 40 Cu(II) cations in the unit cell. I am trying to calculate the energy for the different spin distributions. However, only in a couple of cases I obtain the signs of the spins that I specified in the input file. For instance, for