[Pw_forum] Re: Pw_forum digest, Vol 1 #825 - 3 msgs

[You Lin]

Dear Paolo:

Thanks for the response. Yes, it works. However, it is still a mistery to 
me that Rahman-Parrinello damped md does break sysmmetry in this case. 

Your help is greatly appreciated.

On Sun, 4 Dec 2005 pw_forum-request at pwscf.org wrote:

> From: Paolo Giannozzi <giannozz at nest.sns.it>
> Organization: Scuola Normale Superiore
> To: pw_forum at pwscf.org
> Subject: Re: [Pw_forum] Help about vc-relax
> Date: Sat, 3 Dec 2005 10:39:13 +0100
> Reply-To: pw_forum at pwscf.org
> 
> On Wednesday 23 November 2005 22:48, You Lin wrote:
> 
> > I'm trying to do a variable cell relaxation [...]
> > The code stops at the second step [...]
> > The error message gives no hint.
> 
> well, it gives a hint, if you know what it means (which is far
> from obvious)...
> 
> >  from checkallsym : error #         2
> >  not orthogonal operation
> 
> this means that the variable-cell relaxation has broken the
> original symmetry of the unit cell. Since the number of k-points
> depends on the symmetry of the cell, the run has to be stopped.
> Possible solutions:
> - start with a nonsymmetric cell
> - use a symmetry-conserving algorithm: the Wentzcovitch algorithm
> (cell_dynamics='damp-w') shouldn't break the symmetry
> 
> Paolo
> 
> -- 
> Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
> Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
> Piazza dei Cavalieri 7      I-56126 Pisa, Italy
> 
> --__--__--
> 
> Message: 3
> From: Paolo Giannozzi <giannozz at nest.sns.it>
> Organization: Scuola Normale Superiore
> To: pw_forum at pwscf.org
> Subject: Re: [Pw_forum] another two problems about the pseudopotential
> Date: Sat, 3 Dec 2005 15:24:38 +0100
> Reply-To: pw_forum at pwscf.org
> 
> On Saturday 03 December 2005 04:07, li yan wrote:
> 
> > what's the meaning fo  PBX PBC?
> 
> PBX = "Perdew-Becke-Ernzerhof gradient correction to exchange"
> PBC = "Perdew-Becke-Ernzerhof gradient correction to correlation"
> 
> > I do some work about AgCl, the pseudopontential of  Ag is given 
> > by fhi98pp, while for Cl , i generated the pseudopotential with pwscf.
> > But the scf.out said that DFT is inconsistent.
> 
> there used to be some inconsistency in the name of the PBE gradient
> corrected functional. Now all codes (atomic, converters, pwscf) use
> the same logic (or lack of it).
> 
> > So can I change directly the PBX PBC to PBE PBE in Cl.UPF to achieve
> > the consistent of  the DFT for Ag and Cl?
> 
> yes, you can
> 
> Paolo
> 
> -- 
> Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
> Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
> Piazza dei Cavalieri 7      I-56126 Pisa, Italy
> 
> 
> --__--__--
> 
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> 
> End of Pw_forum Digest
> 

________________________________________

You Lin

Department of Physics
University of South Florida
4202 East Fowler Avenue
Tampa, FL 33620
________________________________________

Tel: (813)396-9220 [Office]

Homepage: http://shell.cas.usf.edu/~ylin
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