[Pw_forum] Some questions about non-collinear calculation and penalty function

[Sahar Mirshamsi]

Dear Paolo,Cyrille and Mighfar,

It seems you guys are the most active ones in non-collinear field among
forum users. I have posted these questions about two weeks ago and I did
not get any response, can you please take a look at them and tell me your
ideas about possible answers?

Thanks,
Sahar
 

On Fri, 4 Mar 2011, Sahar Mirshamsi wrote:

> On Thu, 3 Mar 2011, Sahar Mirshamsi wrote:
> 
> any idea about answers of these questions?
> 
> Sahar
> 
> 
> > Hi all,
> > I have some questions regarding non-collinear calculation and using
> > penalty function in pwscf.
> > 1)	In constaint_magnetization ='atomic', is starting magnetization as the
> > target magnetization? I have read this post  
> > http://www.democritos.it/pipermail/pw_forum/2009-December/015342.html 
> > and also in input.f90 I found 
> >            mcons(1,nt) = starting_magnetization(nt) * SIN( theta ) * COS(
> > phi )
> >            mcons(2,nt) = starting_magnetization(nt) * SIN( theta ) * SIN(
> > phi )
> >            mcons(3,nt) = starting_magnetization(nt) * COS( theta )
> >  So it means both magnitude and direction of atomic magnetizations are
> > constrained, is this correct?
> > 2)	If above statement is correct, then the same problem as posted in above
> > link will still exist,  since starting_magnetization=m/n, then for
> > constraining the magnitude of magnetization to desired value, we should
> > multiply the magnitude of magnetization by charge and then replace it as
> > starting_magnitization, is this correct?
> > 3)	What is the relation between charge and magnetization printed in scf
> > calculation with those which we can get with using projwf.x, I expect they
> > should get almost same numbers but in scf output for carbons in Graphene
> > nanoribbon I get charge=0.6 and magnetization=0.1 while in projwf.x output
> > I get charge=4 and polarization=0.2-0.3 which the latest one makes more
> > sense.
> > 4)	Also, in some cases of non-collinear calculation with using penalty
> > function, when I track "estimated scf accuracy" it is decreasing till
> > reaching the threshold  and stopping the job while "total energy" is
> > oscillating in some range instead of converging to a number , any idea
> > what's the problem?
> > 5)	The total energy printed in scf calculation does not include constraint
> > energy, right? It's just energy of the structure with the constraint
> > configuration of magnetizations, right?
> > I appreciate any help in finding the answers of these questions.
> > 
> > Sahar Mishamsi
> > Quantum Theory Project and Physics Department,
> > University of Florida
> > 
> > 
> > 
> 
>