Thank you, Brian, for clarifying this! On Wed, Apr 8, 2020 at 11:14 AM Toby, Brian H. <[email protected]> wrote:
> Hi Sergey, > > Both LeBail and Pawley fits are not able to determine phase fractions > because the scale factors are all arbitrary and thus the phase fractions > cannot be refined. However, the reported mass/weight fractions are > determined from the unrefined phase fractions and they are displayed even > though meaningless. > > Brian > > On Apr 8, 2020, at 12:58 PM, Sergey Ushakov via GSAS-II < > [email protected]> wrote: > > Greetings! I have a question maybe not specific to GSAS-II but more about > Pawley vs Le Bail fitting of powder XRD data. > I work on high temperature data from laser-heated solid spheroids which > rotate in a gas flow in aerodynamic levitator. > The data are collected in transmission geometry at 6-ID-D at APS. > The rotation is not well controlled since it depends on the shape of each > bead formed by melt solidification, i.e., on surface tension, volume change > on melting, etc. > So, sometimes data are very much powder-like and amenable to Rietveld > refinement of the structure, but sometimes they are not, and in this case, > I do Pawley fit for cell parameters. > I used to do Le Bail fitting for that in GSAS-I, but I understand that it > was replaced by Pawley refinement (although there is an option for Le Bail > extraction of intensities?). > > To my surprise, Pawley fit in GSAS-II yield phase/weight fraction if one > turns it on for refinement. > I thought phase fraction could be correctly refined only from Rietveld? > > I would appreciate any comments on this! > > Sergey > > -- > Sergey Ushakov PhD > > Staff Research Associate > > Peter A Rock Thermochemistry Laboratory and NEAT ORU > Rm 4415, Chemistry Annex > University of California, Davis > Davis, CA 95616 > > _______________________________________________ > GSAS-II mailing list > [email protected] > https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii > > > -- -- Sergey Ushakov PhD Staff Research Associate Peter A Rock Thermochemistry Laboratory and NEAT ORU Rm 4415, Chemistry Annex University of California, Davis Davis, CA 95616 phone (530) 902-8185
_______________________________________________ GSAS-II mailing list [email protected] https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii
