[Pw_forum] frc_blk question

wlyim at puccini.che.pitt.edu wlyim at puccini.che.pitt.edu
Wed Jun 14 17:47:13 CEST 2006

Dear all,

I am sorry that I shouldn't comment the frc_blk line since it would do 
nothing on the real space force constant.

I re-define my question: what's the main reason for violating the 
hermitian conditions?

Many thanks in advance.

Best regards,

On Wed, 14 Jun 2006 wlyim at puccini.che.pitt.edu wrote:

> Dear all,
> I tried to calculate the phonon structures of surfaces in (1x1) and (2x2) 
> supercells. However, I encountered a problem of violating the Hermitian of 
> dynamical matrix on the (2x2) model, while the (1x1) model had no problem.
> A warning from matdyn.x read like:
>      Max |d(i,j)-d*(j,i)| =  0.008889
>      Max |d(i,j)-d*(j,i)|/|d(i,j)|:  10.7732%
> When I comment the lines calling "frc_blk" in "setupmat" subroutine, the 
> warning disappeared.
> !     call frc_blk (nax_blk,dyn_blk,qp,tau_blk,nat_blk,              &
> !          &              nr1,nr2,nr3,nrx,frc,at_blk,bg_blk,rws,nrws)
> Can anyone help me to clarify what "frc_blk" routine doing?
> Many thanks in advance.
> Best regards,
> William
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Wai-Leung Yim, PhD
Universtaet Oldenburg
Institut fuer Reine und Angewandte Chemie
AG Theoretische Chemie
Carl-von-Ossiezky-Str. 9-11
26129 Oldenburg
Email:	wlyim at puccini.che.pitt.edu
Phone:	+49-441-798-3950 (office)
	+49-441-798-5102 (home)
Fax:	+49-441-798-3964

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