[Pw_forum] Fw : Help on ev.x procedures!!!

[Bertrand SITAMTZE]

Dear Paolo,

Thanks very much for your help. But this does'nt solve my problem. I know there are

-Murnagham EOS
-Second order Birch-Murnagham EOS
-Third order Birch-Murnagham EOS

Please I would like you to have a look at the ev. f90 file in pwtools folder and from the way the EOS are  written, to identify the meaning of the following EOS in this file:

-Birch 1
-Birch 2

Do they mean:

-Second order Birch-Murnagham 
-Third order Birch-Murnagham  ?

In which case we should not lead to a value of B' for second order(usally equal to 4 for this EOS).

Does the Murnagham in this file has the same meaning as in the page 
 http://en.wikipedia.org/wiki/Birch–Murnaghan_equation_of_state  ?


Your answer is of great help for me. Thanks in advance.

*******************************
Bertrand SITAMTZE YOUMBI
Laboratory of material sciences
Department of Physics
University of Yaoundé I-Cameroon
*****************************

--- En date de : Lun 15.2.10, Paolo Giannozzi <giannozz at democritos.it> a écrit :

De: Paolo Giannozzi <giannozz at democritos.it>
Objet: Re: [Pw_forum] Fw : Help on ev.x procedures!!!
À: "PWSCF Forum" <pw_forum at pwscf.org>
Date: Lundi 15 février 2010, 15h49

Bertrand SITAMTZE wrote:

>  Please can somebody help in giving the four EOS use in this file?

most of what you need is here:
   http://en.wikipedia.org/wiki/Birch–Murnaghan_equation_of_state

> What is the unit of the fitting pressure in this file?

I think it is KBar

> Is it correct to have negative pressure?

for expanded systems (V > V_0), it is

P.
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy
_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org
http://www.democritos.it/mailman/listinfo/pw_forum



      
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20100216/72205184/attachment.html>