[Pw_forum] Relax structure after getting the cell

[j.antonio.montoya at gmail.com]

Dear Loc, only at zero pressure H reduces to E. Therefore is clear that, for any pressure different than zero in your two systems, what you need to consider is enthalpy, i.e. compare E+PV for the two systems at the same pressure for both... And also check Wikipedia for more hints on thermodynamics.

Javier Montoya PhD
CIW, DC 20015
USA


------Original Message------
From: loc duong ding
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To: pw_forum at pwscf.org
ReplyTo: PWSCF Forum
Sent: Jan 15, 2009 7:52 PM
Subject: Re: [Pw_forum] Relax structure after getting the cell

> > I know enthalpy is the energy of system at constant pressure.
> 
> really? I knew that H=E+PV
I am sorry for my stupid confusion. 

Anyway, what value (energy or enthalpy) should I use to compare the stability of ground state of two systems?

 -----------------------------------------------
Loc Duong Dinh
Ms-Ph.D Student
Sungkyunkwan Advanced Institute of Nanotechnology,
Sungkyunkwan University,
Suwon, 440-746, Korea 
Email: mambom1902 at yahoo.com 


      
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