On Thu, Feb 2, 2012 at 11:03 PM, Nguyen Doan Sau <ndzsau at yahoo.co.uk> wrote: > Dear Q.E users, > > I am currently carrying a structural relaxation of the crystal structure of > a new oxide compound. There are two new oxides: one I solved its crystal > structure by single crystal X-ray diffraction data and the other is > iso-structural to the first. As I have not been?successful in obtaining the > crystals of the later, I have to use the powder X-ray diffraction data for > solving its crystal structure. I got its unit cell parameter by peak > indexing, using the atomic coordinations of the crystal structure of the > first as its initial atomic coordinations for refinement. > > Okay, I can do the refinement. It went well for the heavy metal atoms but > not for light metal atoms like Li and anion like O (you may suggest using > neutron diffraction for these light atoms. Actually, I talked to my boss > about it but we are unable to have it done before next year. :) Therefore, I > think of another solution: first, obtaining the atomic coordination of the > heavy metal atoms by the refinement; second, structural relax of the lighter > atom (Lithium, oxygen) to obtain their reasonable atomic coordination and > bonds to the heavier atoms. > > ?So far, everything have been going well except for that the relaxation is > time-consuming as the relax involved 204 atoms in the unit cells of volume > of 2750 Ang^3. I use a desktop?equipped?with ?Xeon 2.66 GHz and 8 GB RAM. > The time needed for an average?iteration?is 1 week. I guess it may take me > more than 3 months to have it done properly or just nothing. :) > > Therefore, I would ask for a favor. Is there any way for me to submit my > calculation to a strong computing facility. I would have it done in less > than 2 weeks. I could not give my input here publicly but I can send input > file personally to who kindly want to help.
computer time costs money and is always scarce. as a member of the US research community, however, you can apply for access to an NSF funded supercomputer via XSEDE http://xsede.org/ to expedite the process, please have your adviser contact your local XSEDE campus champion, who already has some discretionary computer time for purposes of getting researchers on XSEDE machines. check out: https://www.xsede.org/web/guest/current-champions cheers, axel. > > Thanks, > Sau Nguyen > Department of Chemistry > University of Houston > > > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Dr. Axel Kohlmeyer akohlmey at gmail.com ?http://goo.gl/1wk0 College of Science and Technology Temple University, Philadelphia PA, USA.
