[GSAS-II] Data processing and data interpretation

[Bernhard Weninger - TNW]

Dear GSAS II community,

I have questions concerning data processing and interpretation with GSAS II. May data concerns in-situ neutron diffraction were I load and unload a sample with hydrogen.
Due to the hydrogen I have a lot of background and this brings me to my question concerning data interpretation:


*       My data residual wR is very low, about 1%. However, this does not say much about the fitting quality as I have a lot of background. Also the unweighted phase residuals RF2 and RF are displayed. Do these values also include the background? And if yes, is there an option to subtract the background implemented in GSAS II?

The second question concerns data processing. My background is changing with hydrogen content and using the sequential refinement tool is very convenient to fit the background. However, as far as I understand, atom fractions inside unit cells cannot be fitted with sequential refinement (modelling hydrogen content during loading and unloading). In order to model the hydrogen content I guess I need to add to each histogram a separate hydrogen containing phase. Then constraints would allow to e.g. link the UC dimensions of these phases while fitting the hydrogen content individually should be possible, right? Would there be other options for data processing?

I am looking forward to hearing from you, thanks in advance.

Kind regards,

Bernhard Weninger
PhD candidate

TU Delft / Materials for Energy Conversion and Storage (MECS)
Faculty of Applied Sciences, dept. of Chemical Engineering
Van der Maasweg 9
2629 HZ Delft
T +31 (0)15 278 2676
M +31 (0)6 3700 6605
E  B.Weninger at tudelft.nl<mailto:B.Weninger at tudelft.nl>

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