[Pw_forum] Phonon DOS

[Subhradip Ghosh]

On Fri, 30 May 2003, Eyvaz Isaev wrote:

Thanks a lot. However, in the old version I mentioned ngauss and degauss
always keeping in mind that it's a metal. That's why I am puzzled a bit.
What I understand from your message is that even though the error message
remains there is nothing wrong in the calculations and I can trust my
results.

Regards,

Subhradip

> Dear Subhradip,
>
> I assume it will not affect for your calculations if
> you have a metallic system.
> But it is very important for polar semiconductors
> where
> splitting of optical modes at the \Gamma point is not
> possible without applying electric field via
> calculation of macroscopic dielectric constant.
> The error means that electric field is not included.
>
> A reason for the message might be you did not
> mention degauss and ngauss parameters for SCF
> calculations (for old versions). For the new version
> there should be three paremeters:  occupations,
> smearing, degauss (in "system" section). If there are
> not, your system is assumed to be semiconductor type.
>
> Besides, I remember my promise. I will do that soon.
>
> Regards,
> Eyvaz.
> Theoretical Physics Department
> Moscow Steel and Alloys Institute
>
> --- Subhradip Ghosh <subhra at physics.rutgers.edu>
> wrote:
> > Hi,
> >
> > I am trying to compute Phonon DOS using the code
> > matdyn.f90. I found that
> > it worked for an insulator but in my case the system
> > is metallic and while
> > I ran the code there is some output generated
> > alongwith an error message
> >
> >
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> >      from matdyn : error #        -1
> >      non-analytic term for q=0 missing !
> >
> >
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> > I traced it back to the code and found that this
> > error message pops up in
> > case we have no dielectric tensor(probably) written
> > in the real-space
> > force constant
> > file. There is a logical switch in the force
> > constant file which comes out
> > to be F in my case and therefore there are no
> > entries of the variable
> > epsil. I have no idea what the remedy is? Is it a
> > serious error or should
> > I ignore it?
> >
> > Thanks in advance,
> >
> > Subhradip
> >
> > PS: My system is not a simple metal, rather a
> > metallic alloy.
> >
> >
> ############################################################################
> > 		     Dr	Subhradip Ghosh
> > 		     Post Doctoral Fellow
> > 		Condensed matter theory group
> > 	        Department of Physics and Astronomy
> >
> ############################################################################
> > Office:                                     |
> > Residence:
> >
> --------------------------------------------|-------------------------------
> > Serin E255                                  |132,
> > South Adelaide Avenue
> > Department of Physics and Astronomy
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> > Rutgers, The State University of New Jersey
> > |Highland Park
> > 136 Frelinghuysen Road                      |NJ
> > 08904
> > Piscataway, NJ 08854-8019                   |USA
> > USA                                         |
> > Email address: subhra at physics.rutgers.edu,
> > |Telephone # :(732)4489266
> >                subhradip at yahoo.com          |
> > Telephone #  : (732)445-4604                |
> >
> ##############################################################################
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############################################################################
		     Dr	Subhradip Ghosh
		     Post Doctoral Fellow
		Condensed matter theory group
	        Department of Physics and Astronomy
############################################################################
Office:                                     | Residence:
--------------------------------------------|-------------------------------
Serin E255                                  |132, South Adelaide Avenue
Department of Physics and Astronomy         |Apartment# 2A
Rutgers, The State University of New Jersey |Highland Park
136 Frelinghuysen Road                      |NJ 08904
Piscataway, NJ 08854-8019                   |USA
USA                                         |
Email address: subhra at physics.rutgers.edu,  |Telephone # :(732)4489266
               subhradip at yahoo.com          |
Telephone #  : (732)445-4604                |
##############################################################################