[Pw_forum] Phonon DOS

[Subhradip Ghosh]

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.

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		     Dr	Subhradip Ghosh
		     Post Doctoral Fellow
		Condensed matter theory group
	        Department of Physics and Astronomy
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