> > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 03 Aug 2009 13:47:54 +0200 > From: "Lorenzo Paulatto" <paulatto at sissa.it> > Subject: Re: [Pw_forum] generating k point weights > To: "PWSCF Forum" <pw_forum at pwscf.org> > Message-ID: <op.ux24d4ila8x26q at paulax> > Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes > > In data 31 luglio 2009 alle ore 16:25:39, Manoj Srivastava > <manoj at phys.ufl.edu> ha scritto: > >> Dear All, >> I was wondering if someone can tell me, how to generate k point weights >> in the BZ. Reference of a paper would be great! > > Dear Manoj, > you can find the algorithm tha tgenerates points and weights in > pwtools/kpoints.f > The obvious reference is the original article from Monkhorst and Pack: Phys. Rev. B 13, 5188 - 5192 (1976), although I don't know if they give an > explicit formulation for the weights there (weights depend on how many symmetry-equivalent copies of a point are present in the set, not on the generation algorithm). > > cheers > > Hello, I would like to point out that pwscf generates k-points slightly differently from the way it was done by Monkhorst and Pack in their original paper. For them, the k-point grid either included or did not include Gamma (zone center) depending on whether the number of divisions was odd or even. However, in PWscf, 'unshifted' grids always include Gamma, and 'shifted' ones do not, regardless of whether the number of divisions is odd or even. To get weights: you have to see how many k points in the full BZ are equivalent to the given point in the IBZ. I have a slide illustrating this in my recent talk at the UCSB Q-E summer school, see my first lecture, slides available at http://www.quantum-espresso.org/wiki/index.php/QESB09
Shobhana Narasimhan Theoretical Sciences Unit Jawaharlal Nehru Centre for Advanced Scientific Research Bangalore