Dear all, Thanks for the insights.
Cheers, Aaron ------------------------------------------ Dr. Aaron Finke Postdoctoral Fellow Swiss Light Source WSLA/217 CH-5232 Villigen-PSI phone: +41 56 310 5652 e-mail: [email protected] On Mar 3, 2015, at 18:43, George Sheldrick <[email protected]> wrote: > Dear Finke, > > SADABS and similar programs work best when given scans about several axes > relative to the crystal. Scanning about a single axis can do more harm than > good especially if the symmetry is low. SADABS can also do a face-indexed > numerical absorption correction too, but this assumes that the crystal is > uniformly bathed in the beam, which is unlikely to be the case with highly > focussed beams. Why don't you use the PSI PRIGO goniometer to scan about > several axes?! > > Best wishes, George > > > On 03.03.2015 17:35, Finke Aaron (PSI) wrote: >> Dear comrades, >> >> This is slightly off-topic but there are enough experts here to warrant >> asking. Here at SLS I occasionally get asked to collect small molecule data >> on the synchrotron. By convention, post-refinement corrections for X-ray >> absorption by the crystal are required for publication in Acta C and E. XDS, >> to my knowledge, does not do this, it just corrects for other absorption >> sources like air. Currently, the most popular absorption correction method >> for small molecules is the psi-scan correction implemented in programs like >> SADABS, but I am wondering if SADABS is appropriate for data collected on a >> single axis, as most synchrotron data is. Also, since we use photon-counting >> detectors (Pilatus), the other correction options for CCD detectors probably >> aren’t appropriate either. I rarely if ever see an improvement in R-factors >> nor other improvements in disagreeable reflections after using SADABS from >> data collected here. What does everyone think? Is psi-scan appropriate, or >> should I resort other methods? >> >> Any insights would be much appreciated. >> >> Best regards, >> Aaron >> ------------------------------------------ >> Dr. Aaron Finke >> Postdoctoral Fellow >> Swiss Light Source >> WSLA/217 >> CH-5232 Villigen-PSI >> phone: +41 56 310 5652 >> e-mail: [email protected] >> > > > -- > Prof. George M. Sheldrick FRS > Dept. Structural Chemistry, > University of Goettingen, > Tammannstr. 4, > D37077 Goettingen, Germany > Tel. +49-551-39-33021 or -33068 > Fax. +49-551-39-22582 > >
