Lachland, Ever been to a Pittsburgh Diffraction Conference? I wonder if you could do a talk on this charge flipping stuff in a session I'm organizing. Meeting is Oct 26-28 in Buffalo. Please let me know ASAP. Bob
________________________________ From: Lachlan Cranswick [mailto:[EMAIL PROTECTED] Sent: Mon 8/13/2007 5:17 PM To: rietveld_l@ill.fr Cc: [EMAIL PROTECTED] Subject: RIET: Charge Flipping applet that shows the magic of the algorithm For those who have not seen it yet: in demonstrating the Charge Flipping strucure solution algorithm of Oszlanyi and Suto [Acta Cryst. (2004), A60, 134-141; Acta Cryst. (2005). A61, 147-152], there is a marvellous Java applet written by Nicolas Schoeni and Gervais Chapuis at: http://escher.epfl.ch/flip/ It can also be downloaded as a standalone file: http://escher.epfl.ch/flip/flip.jar Solving the [2D] structure seems quite magical. Via David Watkin: Create a simple molecule - chlorobenzene - and it will recover it very quickly. Create something with pseudo-symmetry, and it struggles. Fiddle with the axes in the middle pane, and sometimes it works. Even more intriguing, clear the partial solution and simply start the charge flipping again, and because the start is random, it may work. ---------- Charge Flipping is implemented within: Superflip by Lukas Palatinus and Gervais Chapuis http://superspace.epfl.ch/superflip/ Some example files single crystal and powder at: http://superspace.epfl.ch/superflip/examples.html Superflip is a computer program for application of the charge-flipping algorithm to structure solution of crystal structures from diffraction data. Superflip works in arbitrary dimension and can be therefore used for solution of normal periodic structures, modulated structures and also quasicrystals. and Ton Spek's Platon/System S (titled as Flipper): http://www.cryst.chem.uu.nl/platon/ ftp://xraysoft.chem.uu.nl/pub -------- The latest distribution of the Crystals single crystal suite (1 July 2007) has a link to Superflip provided by Arie van der Lee http://www.xtl.ox.ac.uk/download.html - put the superflip Windows executable in the c:\wincrys directory - make sure c:\wincrys is in the path statement - read Superflip manual for options (if tweaking the superflip file): http://superspace.epfl.ch/superflip/download/superflip_user_manual.pdf - then accessible via Crystals menu: Solve, Superflip ----- For powder diffraction data and SuperFlip, refer: Charge flipping on powder diffraction data: Baerlocher Ch., McCusker L. B., Palatinus L. (2007), Z. Kristallogr. 222(2), 47-53 Lachlan. ----------------------- Lachlan M. D. Cranswick Contact outside working hours / Coordonnees en dehors des heures de travail: NEW E-mail / courriel: lc *at* bluehaze.com.au Home Tel: (613) 584-4226 ; WWW: http://lachlan.bluehaze.com.au/ P.O. Box 2057, Deep River, Ontario, Canada, K0J 1P0 (please use clear titles in any Email - otherwise messages might accidentally get put in the SPAM list due to large amount of junk Email being received. If you don't get an expected reply to any messages, please try again.) (Essayez d'utiliser des titres explicites - sans quoi vos messages pourraient aboutir dans un dossier de rebuts, du fait de la quantite tres importante de pourriels recue. Si vous n'obtenez pas la reponse attendue, merci de bien vouloir renvoyer un message.)
