[Pw_forum] phonon at G error : from phq_readin : error # 1 no elec. field with metals
njuxuyuehua at gmail.com
Tue May 22 15:46:10 CEST 2007
Dear Prof Nicola Marzari:
thank you for your help , i am really grateful i will read the paper and
book you have recommended to me.
if there is some question about the paper i would like to consult with you
.Hope get your help .
2007/5/22, Nicola Marzari <marzari at mit.edu>:
> xu yuehua wrote:
> > yes,before pho calculation ,i have computed "scf" .the water. in is this
> > &system
> > ibrav = 0,
> > nat = 15,
> > ntyp = 2,
> > ecutwfc = 29.98744D0,
> > ecutrho =200
> > occupations = "smearing",
> > smearing = "gauss",
> > degauss = 0.003D0,
> > if it is unsuitable ,i have no idea to use what occupations and so on
> > .please help me .thanks
> > my name is xu yuehua
> > affilation: physics depatment
> > nanjing university china.
> Dear Xu,
> welcome to the gang.
> There are two comments to make here - if you want your calculation to
> work, start by droppping the keywords for occupations, smearing, and
> degauss. Those three are used for systems with fractional occupations -
> these are typically metals, and that's why phonon stopped. By the
> way, "Phonon" calculation for the water molecule and the water dimer
> are available in a 2005 JCP by Sit and Marzari - you could compare your
> results and parameters with those.
> The second comment is that even completing your calculations
> successfully won't be very helpful, if you do not first become
> experienced in this kind of calculations.
> Now, I'm not sure what to suggest - there is a book on "Electronic
> Structure" by Richard Martin that is outstanding, but a bit advanced.
> A more introductory one has recently come out, by Jorge Kohanoff
> ("Electronic Structure Calculations for Solids and Molecules).
> I might sound self-serving, but our graduate class on atomistic
> modeling of materials (including video lectures, and pwscf homework),
> is fully on the web, linked from
> http://quasiamore.mit.edu/pmwiki/index.php?n=Main.Teaching ).
> This class takes MIT students of different backgrounds, and that
> have never seen computational modeling, through a basic knowledge
> of the fundamentals.
> Prof Nicola Marzari Department of Materials Science and Engineering
> 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA
> tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu
> Pw_forum mailing list
> Pw_forum at pwscf.org
physics Department of Nanjing university
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