Hello! I am about to calculate the phonon spectrum with siesta and have several questions:
Does anyone knows a publication wher is described what SIESTA and VIBRA calculates and more important how it does the Calculations? I have 6 Atoms in the unitcell and 3x3x3xunitcell=162 atoms in the supercell. So far I couldn't finish a FC calculation and there seems no reasonable restart function. I don't know how many atoms will siesta move? It seems to me that SIESTA completly forgets about the symmetries of the supercell, on the other hand it starts with an atom of the Cell in the middle of the block. Can it be that I just need to to Calculate the six atoms of the middle unitcell, one after another and assemble the resulting FC-Files into one FC-File and Vibra will do the rest for me? Can I use order N solution method with Phonon (FC and Vibra) calculation? I think the orderN algorythm just calculates the gamma point, if it is so, wouldn't it be useless for an Phononcalculation as I will need a good k-grid for reasonable results? Thanks in advanced, Best, Lydia Nemec -- Lydia Nemec ======================================================= Sector of Biological and Soft Systems Department of Physics, University of Cambridge Cavendish Laboratory J J Thomson Avenue, Cambridge CB3 0HE, UK Tel. 0044(01223)3-37357 Email: ln...@cam.ac.uk ------------------------------------------------------- Institute for Theoretical Physics University Regensburg 93040 Regensburg, Germany =======================================================
