[Pw_forum] Fwd: Phase transtion calculation

[Stefano Baroni]

On Aug 20, 2007, at 11:37 AM, Joshi Mitesh wrote:

>
>
>
> Hi users,
>              I am in a learning phase of pwscf and now trying to  
> calculate phase transition,
> I take a simple example AlAs and calculate the total energies -  
> volume for Zincblende (ZB) and Rocksalt (NaCl) Structures,
> but when I plot Enthalpy ( H = E +PV ) --> P  curve after fitting  
> EOS  using ev.x.  the curves  crosses at 0 kbar. which is wrong.
> what shoud be the error ? am I doing a silly mistake ?

Most probably.
Have you tried to repproduce first the E vs. V data of, say, Mujica,  
Needs, and Munoz (PRB 52, 8881, 1995)? Have you paid attention to the  
fact that the NaCl phase is metallic and requires therefore a special  
care for the k-point integration?

Cheers - SB

---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

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