On 16/10/2016 09:32, Alwaleed Ahmed Adllan ahmed Abusin wrote: > Dear ALL > > /I'm trying to do phonon calculation for graphene monolayer > / > > /with high q-point and kpoint 30x30x30 and 60x60x60 respectively > /
You really need to work on the fundamental of electronic structure before starting a calculations, and/or look at papers that have done this before. you'd understand why it might be more relevant to use a mesh that has no sampling in the perpendicular direction, and much fewer k and q points - I'd start with 4x4x1 and 8x8x1 respectively (the number of calculations you have to do is linearly proportional to the number of q points, and the cost of each is proportional to the k-points - your suggested meshes would make each calculation 3375 times more expensive, and you'd need to do 1687 times more calculations - so overall 570,000 times more expensive. I.e. if my suggestion takes a day, your suggestion will take 1561 years. nicola -- ---------------------------------------------------------------------- Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL Director, National Centre for Competence in Research NCCR MARVEL, EPFL http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum