On Jul 30 2007, Jean Bréfort wrote: CML has two mechanisms for crystal structures. (a) lattice and latticeVectors (b) crystal and either scalar (6) or cellParameter(2)
Either of these should be able to support the requirement. The example given below uses lattice and scalar. If these are CML thei is not the recommended combination. If they are not, what is the namespace, becuase otherwise there will be serious clashes. Also lattice does not have an abundance attribute in CML and I'm not sure what the role of this is here. P. >Le lundi 30 juillet 2007 à 09:04 +0300, Jonas Frantz a écrit : >> Hi, >> >> the problem here is that bodr is defining the vectors for each element, >> this is completely redundant as most of the crystal structures can be >> described as a function of lattice structure (hcp, fcc, bcc and so on), >> the length of the unit cell vectors a,b,c and the angles of these alfa, >> beta, gamma. This would allow full description of the more exotic >> crystal structures as well. Have a look at for instance >> http://www.webelements.com/webelements/elements/text/Si/xtal.html for a >> source of these parameters. > >You might notice that they also give the space group, not the Bravais >lattice. > >> The vectors for each crystalstructure can then be described as the >> vectors for each atom within the unit cell and the unitvectors. >> >> What this is practice means: - Reduce the crystalstructure.xml to only >> contain the separate crystalstructures with unitvectors in terms of the >> lattice constant. - Introduce a couple of new fields per element in >> elements.xml. >> >> Regarding introducing the new fields to elements.xml, I guess you would >> want to do it in this fashion (note that for fcc all vectors are equal): >> >> <lattice abundance="1.0"> >> <label name="structure" value="fcc" /> >> <scalar name="lattice_a" value="3.564" unit="angstrom" /> >> <scalar name="lattice_b" value="3.564" unit="angstrom" /> >> <scalar name="lattice_c" value="3.564" unit="angstrom" /> >> <scalar name="lattice_alfa" value="90" unit="degrees" /> >> <scalar name="lattice_beta" value="90" unit="degrees" /> >> <scalar name="lattice_gamma" value="90" unit="degrees" /> >> </lattice> > -- Peter Murray-Rust Unilever Centre for Molecular Informatics Chemistry Department, Cambridge University Lensfield Road, CAMBRIDGE, CB2 1EW, UK Tel: +44-1223-763069 Fax: +44 1223 763076 ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Blueobelisk-discuss mailing list Blueobelisk-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/blueobelisk-discuss
