Could anybody explain how to correctly use distributions instead of Delf in MAUD? Particularly, which is the meaning of Weight, Crystallite Delta, and Variance parameters? What x means in the function plot and which is the unit? How crystallite size (in the "isotropic" folder) influences all these parameters? Does it still makes sense when using distributions? Thank you.
I managed to catch Prof. Lutterotti and this is info from him (thank you, Luca!)
OK, "Distributions" in MAUD are for Line Broadening Model, meaning, that they influence peak profile shape; mean crystallite size and r.m.s. microstrain appear in "Size-Strain model". You may use "Distributions" together with "Anisotropic no rules", or "Popa rules", in this case you will have anisotropic shape for crystallites, and distribution for their sizes.
Concerning parameters of "Distributions". For size distribution the parameter "Variance" is, as you may expect, the variance of distribution; the mean value is taken from "Size-Strain" model part (you refine it there). The "Weight" and the "Crystallite delta" are used if there is a multimodal distribution. E.g., if you have 2 distributions to describe your sample, you should assign correct "Weight"s to them (they add up to 1). For the second distribution you may change "Crystallite delta". It means that the mean size for the second distribution will be shifted by this value.
The same things apply to parameters "Weight" and "Microstrain delta" for "Microstrain". And the "Slope coefficient" parameter is the exponent, it should be between 0 and 1, were 0 is for random dislocation distribution in material.
I will try to get some references from Prof. Lutterotti... For size distributions implemented in MAUD you may see N.C. Popa and D. Balzar. J. Appl. Cryst. (2002) 35, 338-346.
I managed to catch Prof. Lutterotti and this is info from him (thank you, Luca!)
OK, "Distributions" in MAUD are for Line Broadening Model, meaning, that they influence peak profile shape; mean crystallite size and r.m.s. microstrain appear in "Size-Strain model". You may use "Distributions" together with "Anisotropic no rules", or "Popa rules", in this case you will have anisotropic shape for crystallites, and distribution for their sizes.
Concerning parameters of "Distributions". For size distribution the parameter "Variance" is, as you may expect, the variance of distribution; the mean value is taken from "Size-Strain" model part (you refine it there). The "Weight" and the "Crystallite delta" are used if there is a multimodal distribution. E.g., if you have 2 distributions to describe your sample, you should assign correct "Weight"s to them (they add up to 1). For the second distribution you may change "Crystallite delta". It means that the mean size for the second distribution will be shifted by this value.
The same things apply to parameters "Weight" and "Microstrain delta" for "Microstrain". And the "Slope coefficient" parameter is the exponent, it should be between 0 and 1, were 0 is for random dislocation distribution in material.
I will try to get some references from Prof. Lutterotti... For size distributions implemented in MAUD you may see N.C. Popa and D. Balzar. J. Appl. Cryst. (2002) 35, 338-346.
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