Lakshminarasimhan Narayanan said: > Dear All, > > I request you to clarify the following doubts that I have regarding > refinement ( I am using FullProf program): > > 1. While refining the x,y,z coordinates of an atom, the codes should be > same for all three or different? >
Different in most cases. Allthough, if the coordinates are related by symmetry, like for example: if x=x1, y=x1+1/2, z=z1, x and y should have the same code (can't check this right now, just how I remember it is). > 2. While refining the Boverall for the X-ray data, I am ending with a > negative value, is it acceptable? > No. To help with that one really should have the data and pcr-file to look at. Try the refinement sequence as it is given in the help file (pdf) of the latest FullProf version. > 3. For X-ray data, if there are 3-4 types of O atoms in the crystal > structure, whether the Biso should be refined simultaneously by giving the > same code number or individually refined by giving different code numbers. > > Different codes. Different bonding environements can result in different displacement parameters. On the other hand, it may be that oxygen Biso refinement against X-ray data will not succeed anyhow, regardless how you do the refinement. -All the best! Markus -- Markus Valkeap��, [EMAIL PROTECTED] Inorganic Chemistry, G�teborg University tel: +46 (0)31 772 2857; fax: +46 (0)31 772 2853 mail: Oorganisk kemi GU, SE-412 96 Gothenburg, Sweden
